Sexual Behaviour of Men and Women within Age-Disparate Partnerships in South Africa: Implications for Young Women's HIV Risk
Identifieur interne : 002908 ( Pmc/Corpus ); précédent : 002907; suivant : 002909Sexual Behaviour of Men and Women within Age-Disparate Partnerships in South Africa: Implications for Young Women's HIV Risk
Auteurs : Brendan Maughan-Brown ; Meredith Evans ; Gavin GeorgeSource :
- PLoS ONE [ 1932-6203 ] ; 2016.
Abstract
Age-disparate partnerships are hypothesized to increase HIV-risk for young women. However, the evidence base remains mixed. Most studies have focused only on unprotected sex among women in the partnership. Consequently, little is known about other risky behaviours, such as transactional sex, alcohol use, and concurrency, as well as the behaviours of the men who partner with young women. We therefore examined differences in various sexual behaviours of both young women and their male partners by partnership age difference.
We used nationally representative data from South Africa (2012) on partnerships reported by 16–24 year old black African women (n = 818) and by black African men in partnerships with 16–24 year old women (n = 985). We compared sexual behaviours in age-disparate partnerships and age-similar partnerships, using multiple logistic regression to control for potential confounders and to assess rural/urban differences.
Young women in age-disparate partnerships were more likely to report unprotected sex than young women in similar-aged partnerships (aOR:1.51; p = 0.014; 95%CI:1.09–2.11). Men in partnerships with young women were more likely to report unprotected sex (aOR:1.92; p<0.01; 95%CI:1.31–2.81), transactional sex (aOR:2.73; p<0.01; 95%CI:1.64–4.56), drinking alcohol before sex (aOR:1.60; p = 0.062; 95%CI:0.98–2.61), and concurrency (aOR:1.39; p = 0.097; 95%CI:0.94–2.07) when their partners were five or more years younger. The association between age-disparate partnerships and transactional sex (aOR:4.14; p<0.01; 95%CI: 2.03–8.46) and alcohol use (aOR:2.24; p<0.013; 95%CI:1.20–4.19) was only found in urban areas.
Results provide evidence that young women’s age-disparate partnerships involve greater sexual risk, particularly through the risky behaviours of their male partners, with the risk amplified for young women in urban areas.
Url:
DOI: 10.1371/journal.pone.0159162
PubMed: 27526116
PubMed Central: 4985138
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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Sexual Behaviour of Men and Women within Age-Disparate Partnerships in South Africa: Implications for Young Women's HIV Risk</title><author><name sortKey="Maughan Brown, Brendan" sort="Maughan Brown, Brendan" uniqKey="Maughan Brown B" first="Brendan" last="Maughan-Brown">Brendan Maughan-Brown</name><affiliation><nlm:aff id="aff001"><addr-line>Southern Africa Labour and Development Research Unit (SALDRU), Department of Economics, University of Cape Town, Cape Town, South Africa</addr-line></nlm:aff></affiliation></author><author><name sortKey="Evans, Meredith" sort="Evans, Meredith" uniqKey="Evans M" first="Meredith" last="Evans">Meredith Evans</name><affiliation><nlm:aff id="aff002"><addr-line>The Institute for Humanities in Africa (HUMA), Department of Sociology, University of Cape Town, Cape Town, South Africa</addr-line></nlm:aff></affiliation></author><author><name sortKey="George, Gavin" sort="George, Gavin" uniqKey="George G" first="Gavin" last="George">Gavin George</name><affiliation><nlm:aff id="aff003"><addr-line>Health Economics and HIV and AIDS Research Division (HEARD), University of KwaZulu-Natal, Durban, South Africa</addr-line></nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">27526116</idno><idno type="pmc">4985138</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985138</idno><idno type="RBID">PMC:4985138</idno><idno type="doi">10.1371/journal.pone.0159162</idno><date when="2016">2016</date><idno type="wicri:Area/Pmc/Corpus">002908</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">002908</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">Sexual Behaviour of Men and Women within Age-Disparate Partnerships in South Africa: Implications for Young Women's HIV Risk</title><author><name sortKey="Maughan Brown, Brendan" sort="Maughan Brown, Brendan" uniqKey="Maughan Brown B" first="Brendan" last="Maughan-Brown">Brendan Maughan-Brown</name><affiliation><nlm:aff id="aff001"><addr-line>Southern Africa Labour and Development Research Unit (SALDRU), Department of Economics, University of Cape Town, Cape Town, South Africa</addr-line></nlm:aff></affiliation></author><author><name sortKey="Evans, Meredith" sort="Evans, Meredith" uniqKey="Evans M" first="Meredith" last="Evans">Meredith Evans</name><affiliation><nlm:aff id="aff002"><addr-line>The Institute for Humanities in Africa (HUMA), Department of Sociology, University of Cape Town, Cape Town, South Africa</addr-line></nlm:aff></affiliation></author><author><name sortKey="George, Gavin" sort="George, Gavin" uniqKey="George G" first="Gavin" last="George">Gavin George</name><affiliation><nlm:aff id="aff003"><addr-line>Health Economics and HIV and AIDS Research Division (HEARD), University of KwaZulu-Natal, Durban, South Africa</addr-line></nlm:aff></affiliation></author></analytic><series><title level="j">PLoS ONE</title><idno type="eISSN">1932-6203</idno><imprint><date when="2016">2016</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><sec id="sec001"><title>Background</title><p>Age-disparate partnerships are hypothesized to increase HIV-risk for young women. However, the evidence base remains mixed. Most studies have focused only on unprotected sex among women in the partnership. Consequently, little is known about other risky behaviours, such as transactional sex, alcohol use, and concurrency, as well as the behaviours of the men who partner with young women. We therefore examined differences in various sexual behaviours of both young women and their male partners by partnership age difference.</p></sec><sec id="sec002"><title>Methods</title><p>We used nationally representative data from South Africa (2012) on partnerships reported by 16–24 year old black African women (n = 818) and by black African men in partnerships with 16–24 year old women (n = 985). We compared sexual behaviours in age-disparate partnerships and age-similar partnerships, using multiple logistic regression to control for potential confounders and to assess rural/urban differences.</p></sec><sec id="sec003"><title>Results</title><p>Young women in age-disparate partnerships were more likely to report unprotected sex than young women in similar-aged partnerships (aOR:1.51; p = 0.014; 95%CI:1.09–2.11). Men in partnerships with young women were more likely to report unprotected sex (aOR:1.92; p<0.01; 95%CI:1.31–2.81), transactional sex (aOR:2.73; p<0.01; 95%CI:1.64–4.56), drinking alcohol before sex (aOR:1.60; p = 0.062; 95%CI:0.98–2.61), and concurrency (aOR:1.39; p = 0.097; 95%CI:0.94–2.07) when their partners were five or more years younger. The association between age-disparate partnerships and transactional sex (aOR:4.14; p<0.01; 95%CI: 2.03–8.46) and alcohol use (aOR:2.24; p<0.013; 95%CI:1.20–4.19) was only found in urban areas.</p></sec><sec id="sec004"><title>Conclusions</title><p>Results provide evidence that young women’s age-disparate partnerships involve greater sexual risk, particularly through the risky behaviours of their male partners, with the risk amplified for young women in urban areas.</p></sec></div></front><back><div1 type="bibliography"><listBibl><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Harling, G" uniqKey="Harling G">G Harling</name></author><author><name sortKey="Newell, M L" uniqKey="Newell M">M-L Newell</name></author><author><name sortKey="Tanser, F" uniqKey="Tanser F">F Tanser</name></author><author><name sortKey="Kawachi, I" uniqKey="Kawachi I">I Kawachi</name></author><author><name sortKey="Subramanian, Sv" uniqKey="Subramanian S">SV Subramanian</name></author><author><name sortKey="Barnighausen, T" uniqKey="Barnighausen T">T Barnighausen</name></author></analytic></biblStruct><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Hope, R" uniqKey="Hope R">R Hope</name></author></analytic></biblStruct><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Balkus, Je" uniqKey="Balkus J">JE Balkus</name></author><author><name sortKey="Nair, G" uniqKey="Nair G">G Nair</name></author><author><name sortKey="Montgomery, Et" uniqKey="Montgomery E">ET Montgomery</name></author><author><name sortKey="Mishra, A" uniqKey="Mishra A">A Mishra</name></author><author><name sortKey="Palanee Phillips, T" uniqKey="Palanee Phillips T">T Palanee-Phillips</name></author><author><name sortKey="Ramjee, G" uniqKey="Ramjee G">G Ramjee</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Gregson, S" uniqKey="Gregson S">S Gregson</name></author><author><name sortKey="Nyamukapa, C" uniqKey="Nyamukapa C">C Nyamukapa</name></author><author><name sortKey="Garnett, G" uniqKey="Garnett G">G Garnett</name></author><author><name sortKey="Mason, P" uniqKey="Mason P">P Mason</name></author><author><name sortKey="Zhuwau, T" uniqKey="Zhuwau T">T Zhuwau</name></author><author><name sortKey="Carael, M" uniqKey="Carael M">M Caraël</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Katz, I" uniqKey="Katz I">I Katz</name></author><author><name sortKey="Low Beer, D" uniqKey="Low Beer D">D Low-Beer</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kelly, Rj" uniqKey="Kelly R">RJ Kelly</name></author><author><name sortKey="Gray, Rh" uniqKey="Gray R">RH Gray</name></author><author><name sortKey="Sewankambo, Nk" uniqKey="Sewankambo N">NK Sewankambo</name></author><author><name sortKey="Serwadda, D" uniqKey="Serwadda D">D Serwadda</name></author><author><name sortKey="Wabwire Mangen, F" uniqKey="Wabwire Mangen F">F Wabwire-Mangen</name></author><author><name sortKey="Lutalo, T" uniqKey="Lutalo T">T Lutalo</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Pettifor, A" uniqKey="Pettifor A">A Pettifor</name></author><author><name sortKey="Rees, H" uniqKey="Rees H">H Rees</name></author><author><name sortKey="Kleinschmidt, I" uniqKey="Kleinschmidt I">I Kleinschmidt</name></author><author><name sortKey="Steffenson, A" uniqKey="Steffenson A">A Steffenson</name></author><author><name sortKey="Macphail, C" uniqKey="Macphail C">C MacPhail</name></author><author><name sortKey="Hlongwa Madikizela, L" uniqKey="Hlongwa Madikizela L">L Hlongwa-Madikizela</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chapman, R" uniqKey="Chapman R">R Chapman</name></author><author><name sortKey="White, Rg" uniqKey="White R">RG White</name></author><author><name sortKey="Shafer, La" uniqKey="Shafer L">LA Shafer</name></author><author><name sortKey="Pettifor, A" uniqKey="Pettifor A">A Pettifor</name></author><author><name sortKey="Mugurungi, O" uniqKey="Mugurungi O">O Mugurungi</name></author><author><name sortKey="Ross, D" uniqKey="Ross D">D Ross</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Baird, Sj" uniqKey="Baird S">SJ Baird</name></author><author><name sortKey="Garfein, Rs" uniqKey="Garfein R">RS Garfein</name></author><author><name sortKey="Mcintosh, Ct" uniqKey="Mcintosh C">CT McIntosh</name></author><author><name sortKey="Ozler, B" uniqKey="Ozler B">B Ozler</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dupas, P" uniqKey="Dupas P">P Dupas</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Luke, N" uniqKey="Luke N">N Luke</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Luke, N" uniqKey="Luke N">N Luke</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bankole, A" uniqKey="Bankole A">A Bankole</name></author><author><name sortKey="Ahmed, Fh" uniqKey="Ahmed F">FH Ahmed</name></author><author><name sortKey="Neema, S" uniqKey="Neema S">S Neema</name></author><author><name sortKey="Ouedraogo, C" uniqKey="Ouedraogo C">C Ouedraogo</name></author><author><name sortKey="Konyani, S" uniqKey="Konyani S">S Konyani</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Langeni, T" uniqKey="Langeni T">T Langeni</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Malema, Bw" uniqKey="Malema B">BW Malema</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Beauclair, R" uniqKey="Beauclair R">R Beauclair</name></author><author><name sortKey="Kassanjee, R" uniqKey="Kassanjee R">R Kassanjee</name></author><author><name sortKey="Temmerman, M" uniqKey="Temmerman M">M Temmerman</name></author><author><name sortKey="Welte, A" uniqKey="Welte A">A Welte</name></author><author><name sortKey="Delva, W" uniqKey="Delva W">W Delva</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Volpe, E" uniqKey="Volpe E">E Volpe</name></author><author><name sortKey="Hardie, T" uniqKey="Hardie T">T Hardie</name></author><author><name sortKey="Cerulli, C" uniqKey="Cerulli C">C Cerulli</name></author><author><name sortKey="Sommers, M" uniqKey="Sommers M">M Sommers</name></author><author><name sortKey="Morrison Beedy, M" uniqKey="Morrison Beedy M">M Morrison-Beedy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Leclerc Madlala, S" uniqKey="Leclerc Madlala S">S Leclerc-Madlala</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wamoyi, J" uniqKey="Wamoyi J">J Wamoyi</name></author><author><name sortKey="Fenwick, A" uniqKey="Fenwick A">A Fenwick</name></author><author><name sortKey="Urassa, M" uniqKey="Urassa M">M Urassa</name></author><author><name sortKey="Zaba, B" uniqKey="Zaba B">B Zaba</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Zembe, Y" uniqKey="Zembe Y">Y Zembe</name></author><author><name sortKey="Townsend, L" uniqKey="Townsend L">L Townsend</name></author><author><name sortKey="Thorson, A" uniqKey="Thorson A">A Thorson</name></author><author><name sortKey="Ekstrom, Am" uniqKey="Ekstrom A">AM Ekström</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kaufman, Ce" uniqKey="Kaufman C">CE Kaufman</name></author><author><name sortKey="Stavrou, Se" uniqKey="Stavrou S">SE Stavrou</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Leclerc Madlala, S" uniqKey="Leclerc Madlala S">S Leclerc-Madlala</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Miller, Ks" uniqKey="Miller K">KS Miller</name></author><author><name sortKey="Clark, Lf" uniqKey="Clark L">LF Clark</name></author><author><name sortKey="Moore, Js" uniqKey="Moore J">JS Moore</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wood, K" uniqKey="Wood K">K Wood</name></author><author><name sortKey="Maforah, F" uniqKey="Maforah F">F Maforah</name></author><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Britton, A" uniqKey="Britton A">A Britton</name></author><author><name sortKey="Ben Shlomo, Y" uniqKey="Ben Shlomo Y">Y Ben-Shlomo</name></author><author><name sortKey="Benzeval, M" uniqKey="Benzeval M">M Benzeval</name></author><author><name sortKey="Kuh, D" uniqKey="Kuh D">D Kuh</name></author><author><name sortKey="Bell, S" uniqKey="Bell S">S Bell</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Maughan Brown, B" uniqKey="Maughan Brown B">B Maughan-Brown</name></author><author><name sortKey="Kenyon, C" uniqKey="Kenyon C">C Kenyon</name></author><author><name sortKey="Lurie, Mn" uniqKey="Lurie M">MN Lurie</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lurie, M" uniqKey="Lurie M">M Lurie</name></author><author><name sortKey="Pronyk, P" uniqKey="Pronyk P">P Pronyk</name></author><author><name sortKey="De Moor, E" uniqKey="De Moor E">E de Moor</name></author><author><name sortKey="Heyer, A" uniqKey="Heyer A">A Heyer</name></author><author><name sortKey="De Bruyn, G" uniqKey="De Bruyn G">G de Bruyn</name></author><author><name sortKey="Struthers, H" uniqKey="Struthers H">H Struthers</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Darj, E" uniqKey="Darj E">E Darj</name></author><author><name sortKey="Mirembe, Fm" uniqKey="Mirembe F">FM Mirembe</name></author><author><name sortKey="R Ssjo, E B" uniqKey="R Ssjo E">E-B Råssjö</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dodoo, Fn A" uniqKey="Dodoo F">FN-A Dodoo</name></author><author><name sortKey="Zulu, Em" uniqKey="Zulu E">EM Zulu</name></author><author><name sortKey="Ezeh, Ac" uniqKey="Ezeh A">AC Ezeh</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tumwesigye, Nm" uniqKey="Tumwesigye N">NM Tumwesigye</name></author><author><name sortKey="Ingham, R" uniqKey="Ingham R">R Ingham</name></author><author><name sortKey="Holmes, D" uniqKey="Holmes D">D Holmes</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Voeten, H" uniqKey="Voeten H">H Voeten</name></author><author><name sortKey="Egesah, O" uniqKey="Egesah O">O Egesah</name></author><author><name sortKey="Habbema, J" uniqKey="Habbema J">J Habbema</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Voeten, H" uniqKey="Voeten H">H Voeten</name></author><author><name sortKey="Egesah, O" uniqKey="Egesah O">O Egesah</name></author><author><name sortKey="Varkevisser, C" uniqKey="Varkevisser C">C Varkevisser</name></author><author><name sortKey="Habbema, J" uniqKey="Habbema J">J Habbema</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Papo, Jk" uniqKey="Papo J">JK Papo</name></author><author><name sortKey="Bauni, Ek" uniqKey="Bauni E">EK Bauni</name></author><author><name sortKey="Sanders, Ej" uniqKey="Sanders E">EJ Sanders</name></author><author><name sortKey="Brocklehurst, P" uniqKey="Brocklehurst P">P Brocklehurst</name></author><author><name sortKey="Jaffe, Hw" uniqKey="Jaffe H">HW Jaffe</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Johnson, S" uniqKey="Johnson S">S Johnson</name></author><author><name sortKey="Kincaid, Dl" uniqKey="Kincaid D">DL Kincaid</name></author><author><name sortKey="Figueroa, M" uniqKey="Figueroa M">M Figueroa</name></author><author><name sortKey="Delate, R" uniqKey="Delate R">R Delate</name></author><author><name sortKey="Mahlasela, L" uniqKey="Mahlasela L">L Mahlasela</name></author><author><name sortKey="Magni, S" uniqKey="Magni S">S Magni</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shisana, O" uniqKey="Shisana O">O Shisana</name></author><author><name sortKey="Rehle, T" uniqKey="Rehle T">T Rehle</name></author><author><name sortKey="Simbayi, L" uniqKey="Simbayi L">L Simbayi</name></author><author><name sortKey="Zuma, K" uniqKey="Zuma K">K Zuma</name></author><author><name sortKey="Jooste, S" uniqKey="Jooste S">S Jooste</name></author><author><name sortKey="Zunga, N" uniqKey="Zunga N">N Zunga</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kenyon, C" uniqKey="Kenyon C">C Kenyon</name></author><author><name sortKey="Colebunders, R" uniqKey="Colebunders R">R Colebunders</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Morris, M" uniqKey="Morris M">M Morris</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Cameron, Ac" uniqKey="Cameron A">AC Cameron</name></author><author><name sortKey="Miller, Dl" uniqKey="Miller D">DL Miller</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Knaub, Jr" uniqKey="Knaub J">JR Knaub</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schroder, Kee" uniqKey="Schroder K">KEE Schroder</name></author><author><name sortKey="Carey, Mp" uniqKey="Carey M">MP Carey</name></author><author><name sortKey="Vanable, Pa" uniqKey="Vanable P">PA Vanable</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Longfield, K" uniqKey="Longfield K">K Longfield</name></author><author><name sortKey="Glick, A" uniqKey="Glick A">A Glick</name></author><author><name sortKey="Waithaka, M" uniqKey="Waithaka M">M Waithaka</name></author><author><name sortKey="Berman, J" uniqKey="Berman J">J Berman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Silberschmidt, M" uniqKey="Silberschmidt M">M Silberschmidt</name></author><author><name sortKey="Rasch, V" uniqKey="Rasch V">V Rasch</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ott, Mq" uniqKey="Ott M">MQ Ott</name></author><author><name sortKey="B Rnighausen, T" uniqKey="B Rnighausen T">T Bärnighausen</name></author><author><name sortKey="Tanser, F" uniqKey="Tanser F">F Tanser</name></author><author><name sortKey="Lurie, Mn" uniqKey="Lurie M">MN Lurie</name></author><author><name sortKey="Newell, M L" uniqKey="Newell M">M-L Newell</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Karlyn, As" uniqKey="Karlyn A">AS Karlyn</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Masvawure, T" uniqKey="Masvawure T">T Masvawure</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mavhandu Mudzusi, Ah" uniqKey="Mavhandu Mudzusi A">AH Mavhandu-Mudzusi</name></author><author><name sortKey="Sandy, Pt" uniqKey="Sandy P">PT Sandy</name></author><author><name sortKey="Francis, Tk" uniqKey="Francis T">TK Francis</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Nyanzi, S" uniqKey="Nyanzi S">S Nyanzi</name></author><author><name sortKey="Pool, R" uniqKey="Pool R">R Pool</name></author><author><name sortKey="Kinsman, J" uniqKey="Kinsman J">J Kinsman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Hunter, M" uniqKey="Hunter M">M Hunter</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Stephenson, R" uniqKey="Stephenson R">R Stephenson</name></author><author><name sortKey="Winter, A" uniqKey="Winter A">A Winter</name></author><author><name sortKey="Elfstrom, M" uniqKey="Elfstrom M">M Elfstrom</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Choudhry, V" uniqKey="Choudhry V">V Choudhry</name></author><author><name sortKey="Ambresin, A E" uniqKey="Ambresin A">A-E Ambresin</name></author><author><name sortKey="Nyakato, Vn" uniqKey="Nyakato V">VN Nyakato</name></author><author><name sortKey="Agardh, A" uniqKey="Agardh A">A Agardh</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mantell, Je" uniqKey="Mantell J">JE Mantell</name></author><author><name sortKey="Levasseur, Mt" uniqKey="Levasseur M">MT LeVasseur</name></author><author><name sortKey="Sun, X" uniqKey="Sun X">X Sun</name></author><author><name sortKey="Zhou, J" uniqKey="Zhou J">J Zhou</name></author><author><name sortKey="Mao, J" uniqKey="Mao J">J Mao</name></author><author><name sortKey="Peng, Y" uniqKey="Peng Y">Y Peng</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Robinson, J" uniqKey="Robinson J">J Robinson</name></author><author><name sortKey="Yeh, E" uniqKey="Yeh E">E Yeh</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dunkle, K" uniqKey="Dunkle K">K Dunkle</name></author><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author><author><name sortKey="Brown, H" uniqKey="Brown H">H Brown</name></author><author><name sortKey="Gray, G" uniqKey="Gray G">G Gray</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author><author><name sortKey="Morrell, R" uniqKey="Morrell R">R Morrell</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author><author><name sortKey="Morrell, R" uniqKey="Morrell R">R Morrell</name></author><author><name sortKey="Sikweyiya, Y" uniqKey="Sikweyiya Y">Y Sikweyiya</name></author><author><name sortKey="Dunkle, K" uniqKey="Dunkle K">K Dunkle</name></author><author><name sortKey="Penn Kekana, L" uniqKey="Penn Kekana L">L Penn-Kekana</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author><author><name sortKey="Morrell, R" uniqKey="Morrell R">R Morrell</name></author><author><name sortKey="Sikweyiya, Y" uniqKey="Sikweyiya Y">Y Sikweyiya</name></author><author><name sortKey="Dunkle, K" uniqKey="Dunkle K">K Dunkle</name></author><author><name sortKey="Penn Kekana, L" uniqKey="Penn Kekana L">L Penn-Kekana</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Pettifor, Ae" uniqKey="Pettifor A">AE Pettifor</name></author><author><name sortKey="Kleinschmidt, I" uniqKey="Kleinschmidt I">I Kleinschmidt</name></author><author><name sortKey="Levin, J" uniqKey="Levin J">J Levin</name></author><author><name sortKey="Rees, Hv" uniqKey="Rees H">HV Rees</name></author><author><name sortKey="Macphail, C" uniqKey="Macphail C">C MacPhail</name></author><author><name sortKey="Madikizela Hlongwa, L" uniqKey="Madikizela Hlongwa L">L Madikizela-Hlongwa</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bauman, Lj" uniqKey="Bauman L">LJ Bauman</name></author><author><name sortKey="Berman, R" uniqKey="Berman R">R Berman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Macphail, C" uniqKey="Macphail C">C MacPhail</name></author><author><name sortKey="Campbell, C" uniqKey="Campbell C">C Campbell</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fisher, J" uniqKey="Fisher J">J Fisher</name></author><author><name sortKey="Cook, P" uniqKey="Cook P">P Cook</name></author><author><name sortKey="Sam, N" uniqKey="Sam N">N Sam</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kalichman, Sc" uniqKey="Kalichman S">SC Kalichman</name></author><author><name sortKey="Simbayi, Lc" uniqKey="Simbayi L">LC Simbayi</name></author><author><name sortKey="Kaufman, M" uniqKey="Kaufman M">M Kaufman</name></author><author><name sortKey="Cain, D" uniqKey="Cain D">D Cain</name></author><author><name sortKey="Jooste, S" uniqKey="Jooste S">S Jooste</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shisana, O" uniqKey="Shisana O">O Shisana</name></author><author><name sortKey="Rehle, T" uniqKey="Rehle T">T Rehle</name></author><author><name sortKey="Simbayi, L" uniqKey="Simbayi L">L Simbayi</name></author><author><name sortKey="Zuma, K" uniqKey="Zuma K">K Zuma</name></author><author><name sortKey="Jooste, S" uniqKey="Jooste S">S Jooste</name></author><author><name sortKey="Pillay Van Wyk, V" uniqKey="Pillay Van Wyk V">V Pillay-van-Wyk</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lamb, Mr" uniqKey="Lamb M">MR Lamb</name></author><author><name sortKey="Fayorsey, R" uniqKey="Fayorsey R">R Fayorsey</name></author><author><name sortKey="Nuwagaba Biribonwoha, H" uniqKey="Nuwagaba Biribonwoha H">H Nuwagaba-Biribonwoha</name></author><author><name sortKey="Viola, V" uniqKey="Viola V">V Viola</name></author><author><name sortKey="Mutabazi, V" uniqKey="Mutabazi V">V Mutabazi</name></author><author><name sortKey="Alwar, T" uniqKey="Alwar T">T Alwar</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Maughan Brown, B" uniqKey="Maughan Brown B">B Maughan-Brown</name></author><author><name sortKey="Venkataramani, A" uniqKey="Venkataramani A">A Venkataramani</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Harling, G" uniqKey="Harling G">G Harling</name></author><author><name sortKey="Tanser, F" uniqKey="Tanser F">F Tanser</name></author><author><name sortKey="Mutevedzi, T" uniqKey="Mutevedzi T">T Mutevedzi</name></author><author><name sortKey="Barnighausen, T" uniqKey="Barnighausen T">T Barnighausen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dunkle, Kl" uniqKey="Dunkle K">KL Dunkle</name></author><author><name sortKey="Wingood, Gm" uniqKey="Wingood G">GM Wingood</name></author><author><name sortKey="Camp, Cm" uniqKey="Camp C">CM Camp</name></author><author><name sortKey="Diclemente, Rj" uniqKey="Diclemente R">RJ DiClemente</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jewkes, R" uniqKey="Jewkes R">R Jewkes</name></author><author><name sortKey="Dunkle, K" uniqKey="Dunkle K">K Dunkle</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">PLoS One</journal-id><journal-id journal-id-type="iso-abbrev">PLoS ONE</journal-id><journal-id journal-id-type="publisher-id">plos</journal-id><journal-id journal-id-type="pmc">plosone</journal-id><journal-title-group><journal-title>PLoS ONE</journal-title></journal-title-group><issn pub-type="epub">1932-6203</issn><publisher><publisher-name>Public Library of Science</publisher-name><publisher-loc>San Francisco, CA USA</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">27526116</article-id><article-id pub-id-type="pmc">4985138</article-id><article-id pub-id-type="doi">10.1371/journal.pone.0159162</article-id><article-id pub-id-type="publisher-id">PONE-D-16-11640</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Behavior</subject><subj-group><subject>Human Sexual Behavior</subject></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Microbiology</subject><subj-group><subject>Medical Microbiology</subject><subj-group><subject>Microbial Pathogens</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Immunodeficiency Viruses</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Medicine and Health Sciences</subject><subj-group><subject>Pathology and Laboratory Medicine</subject><subj-group><subject>Pathogens</subject><subj-group><subject>Microbial Pathogens</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Immunodeficiency Viruses</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Organisms</subject><subj-group><subject>Viruses</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Immunodeficiency Viruses</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Organisms</subject><subj-group><subject>Viruses</subject><subj-group><subject>Immunodeficiency Viruses</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and life sciences</subject><subj-group><subject>Organisms</subject><subj-group><subject>Viruses</subject><subj-group><subject>RNA viruses</subject><subj-group><subject>Retroviruses</subject><subj-group><subject>Lentivirus</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Microbiology</subject><subj-group><subject>Medical Microbiology</subject><subj-group><subject>Microbial Pathogens</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Retroviruses</subject><subj-group><subject>Lentivirus</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Medicine and Health Sciences</subject><subj-group><subject>Pathology and Laboratory Medicine</subject><subj-group><subject>Pathogens</subject><subj-group><subject>Microbial Pathogens</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Retroviruses</subject><subj-group><subject>Lentivirus</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Organisms</subject><subj-group><subject>Viruses</subject><subj-group><subject>Viral Pathogens</subject><subj-group><subject>Retroviruses</subject><subj-group><subject>Lentivirus</subject><subj-group><subject>HIV</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geography</subject><subj-group><subject>Geographic Areas</subject><subj-group><subject>Urban Areas</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Nutrition</subject><subj-group><subject>Diet</subject><subj-group><subject>Alcohol Consumption</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Medicine and Health Sciences</subject><subj-group><subject>Nutrition</subject><subj-group><subject>Diet</subject><subj-group><subject>Alcohol Consumption</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geography</subject><subj-group><subject>Human Geography</subject><subj-group><subject>Behavioral Geography</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Social Sciences</subject><subj-group><subject>Human Geography</subject><subj-group><subject>Behavioral Geography</subject></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Medicine and health sciences</subject><subj-group><subject>Infectious diseases</subject><subj-group><subject>Viral diseases</subject><subj-group><subject>HIV infections</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geography</subject><subj-group><subject>Geographic Areas</subject><subj-group><subject>Rural Areas</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>People and Places</subject><subj-group><subject>Population Groupings</subject><subj-group><subject>Ethnicities</subject><subj-group><subject>Africans</subject></subj-group></subj-group></subj-group></subj-group></article-categories><title-group><article-title>Sexual Behaviour of Men and Women within Age-Disparate Partnerships in South Africa: Implications for Young Women's HIV Risk</article-title><alt-title alt-title-type="running-head">Sexual Behaviour within Age-Disparate Partnerships</alt-title></title-group><contrib-group><contrib contrib-type="author"><name><surname>Maughan-Brown</surname><given-names>Brendan</given-names></name><xref ref-type="aff" rid="aff001"><sup>1</sup></xref><xref ref-type="corresp" rid="cor001">*</xref></contrib><contrib contrib-type="author"><name><surname>Evans</surname><given-names>Meredith</given-names></name><xref ref-type="aff" rid="aff002"><sup>2</sup></xref></contrib><contrib contrib-type="author"><name><surname>George</surname><given-names>Gavin</given-names></name><xref ref-type="aff" rid="aff003"><sup>3</sup></xref></contrib></contrib-group><aff id="aff001"><label>1</label><addr-line>Southern Africa Labour and Development Research Unit (SALDRU), Department of Economics, University of Cape Town, Cape Town, South Africa</addr-line></aff><aff id="aff002"><label>2</label><addr-line>The Institute for Humanities in Africa (HUMA), Department of Sociology, University of Cape Town, Cape Town, South Africa</addr-line></aff><aff id="aff003"><label>3</label><addr-line>Health Economics and HIV and AIDS Research Division (HEARD), University of KwaZulu-Natal, Durban, South Africa</addr-line></aff><contrib-group><contrib contrib-type="editor"><name><surname>Seeley</surname><given-names>Janet</given-names></name><role>Editor</role><xref ref-type="aff" rid="edit1"></xref></contrib></contrib-group><aff id="edit1"><addr-line>London School of Hygiene and Tropical Medicine, UNITED KINGDOM</addr-line></aff><author-notes><fn fn-type="conflict" id="coi001"><p><bold>Competing Interests: </bold>The authors have declared that no competing interests exist.</p></fn><fn fn-type="con"><p><list list-type="simple"><list-item><p><bold>Conceived and designed the experiments:</bold> BMB ME GG.</p></list-item><list-item><p><bold>Analyzed the data:</bold> BMB ME.</p></list-item><list-item><p><bold>Contributed reagents/materials/analysis tools:</bold> BMB ME GG.</p></list-item><list-item><p><bold>Wrote the paper:</bold> BMB ME GG.</p></list-item></list></p></fn><corresp id="cor001">* E-mail: <email>brendan.maughanbrown@gmail.com</email></corresp></author-notes><pub-date pub-type="epub"><day>15</day><month>8</month><year>2016</year></pub-date><pub-date pub-type="collection"><year>2016</year></pub-date><volume>11</volume><issue>8</issue><elocation-id>e0159162</elocation-id><history><date date-type="received"><day>21</day><month>3</month><year>2016</year></date><date date-type="accepted"><day>28</day><month>6</month><year>2016</year></date></history><permissions><copyright-statement>© 2016 Maughan-Brown et al</copyright-statement><copyright-year>2016</copyright-year><copyright-holder>Maughan-Brown et al</copyright-holder><license xlink:href="http://creativecommons.org/licenses/by/4.0/"><license-p>This is an open access article distributed under the terms of the <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution License</ext-link>, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p></license></permissions><self-uri content-type="pdf" xlink:href="pone.0159162.pdf"></self-uri><abstract><sec id="sec001"><title>Background</title><p>Age-disparate partnerships are hypothesized to increase HIV-risk for young women. However, the evidence base remains mixed. Most studies have focused only on unprotected sex among women in the partnership. Consequently, little is known about other risky behaviours, such as transactional sex, alcohol use, and concurrency, as well as the behaviours of the men who partner with young women. We therefore examined differences in various sexual behaviours of both young women and their male partners by partnership age difference.</p></sec><sec id="sec002"><title>Methods</title><p>We used nationally representative data from South Africa (2012) on partnerships reported by 16–24 year old black African women (n = 818) and by black African men in partnerships with 16–24 year old women (n = 985). We compared sexual behaviours in age-disparate partnerships and age-similar partnerships, using multiple logistic regression to control for potential confounders and to assess rural/urban differences.</p></sec><sec id="sec003"><title>Results</title><p>Young women in age-disparate partnerships were more likely to report unprotected sex than young women in similar-aged partnerships (aOR:1.51; p = 0.014; 95%CI:1.09–2.11). Men in partnerships with young women were more likely to report unprotected sex (aOR:1.92; p<0.01; 95%CI:1.31–2.81), transactional sex (aOR:2.73; p<0.01; 95%CI:1.64–4.56), drinking alcohol before sex (aOR:1.60; p = 0.062; 95%CI:0.98–2.61), and concurrency (aOR:1.39; p = 0.097; 95%CI:0.94–2.07) when their partners were five or more years younger. The association between age-disparate partnerships and transactional sex (aOR:4.14; p<0.01; 95%CI: 2.03–8.46) and alcohol use (aOR:2.24; p<0.013; 95%CI:1.20–4.19) was only found in urban areas.</p></sec><sec id="sec004"><title>Conclusions</title><p>Results provide evidence that young women’s age-disparate partnerships involve greater sexual risk, particularly through the risky behaviours of their male partners, with the risk amplified for young women in urban areas.</p></sec></abstract><funding-group><funding-statement>Brendan Maughan-Brown acknowledges support from the National Research Foundation, South Africa, through the Research Career Advancement Fellowship. The National Research Foundation had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.</funding-statement></funding-group><counts><fig-count count="2"></fig-count><table-count count="3"></table-count><page-count count="16"></page-count></counts><custom-meta-group><custom-meta id="data-availability"><meta-name>Data Availability</meta-name><meta-value>The National HIV Communication Survey (NCS), 2012 Steering Committee is the owner of the data used in our study. Researchers who wish to gain access to these data can contact Dr Saul Johnson (<email>saul.johnson@hda.co.za</email>).</meta-value></custom-meta></custom-meta-group></article-meta><notes><title>Data Availability</title><p>The National HIV Communication Survey (NCS), 2012 Steering Committee is the owner of the data used in our study. Researchers who wish to gain access to these data can contact Dr Saul Johnson (<email>saul.johnson@hda.co.za</email>).</p></notes></front><body><sec sec-type="intro" id="sec005"><title>Introduction</title><p>Young women in southern Africa are a critical target for HIV prevention efforts, as nearly 30% of all new infections occur among women in the 15–24 age cohort [<xref rid="pone.0159162.ref001" ref-type="bibr">1</xref>]. Current national strategic plans for HIV [<xref rid="pone.0159162.ref002" ref-type="bibr">2</xref>], and public health campaigns more generally in sub-Saharan Africa [<xref rid="pone.0159162.ref003" ref-type="bibr">3</xref>–<xref rid="pone.0159162.ref005" ref-type="bibr">5</xref>], include the prevention strategy of reducing the overall number of age-disparate partnerships (typically defined as partnerships with an age-gap between partners of 5 years or more). However, the value of this strategy has recently been called into question by a prospective longitudinal study conducted in a rural setting in KwaZulu-Natal, South Africa [<xref rid="pone.0159162.ref002" ref-type="bibr">2</xref>], and by the VOICE trial, involving participants from Uganda, South Africa, and Zimbabwe [<xref rid="pone.0159162.ref006" ref-type="bibr">6</xref>], neither of which found any significant relationship between age-disparate sex and HIV incidence for young women.</p><p>Mixed evidence on the relationship between age-disparate sex and HIV infection [<xref rid="pone.0159162.ref002" ref-type="bibr">2</xref>,<xref rid="pone.0159162.ref006" ref-type="bibr">6</xref>–<xref rid="pone.0159162.ref011" ref-type="bibr">11</xref>] highlights the need for a better understanding of sexual behaviours in age-disparate partnerships, and the concomitant HIV risks for young women. Previous studies have tended to focus on the sexual behaviours of women in such partnerships, rather than on the behaviours of men, although the latter play a key role in determining HIV risk for their partners. One hypothesis explaining why age-disparate partnerships may not increase HIV risk for young women has to do with the selection of older, lower-risk male partners. This might be feasible in dense, cohesive, social networks if women were to be more accurately informed about the risks associated with older compared to younger men [<xref rid="pone.0159162.ref002" ref-type="bibr">2</xref>]. Evidence that women have considerable agency in partner selection in sub-Saharan Africa also supports the feasibility of this hypothesis [<xref rid="pone.0159162.ref012" ref-type="bibr">12</xref>–<xref rid="pone.0159162.ref015" ref-type="bibr">15</xref>].</p><p>In addition, while previous research has established that unprotected sex is more likely in age-disparate partnerships [<xref rid="pone.0159162.ref015" ref-type="bibr">15</xref>–<xref rid="pone.0159162.ref020" ref-type="bibr">20</xref>], there is little quantitative evidence on other risk behaviours, such as transactional sex, alcohol consumption and concurrent sexual partnerships. Qualitative evidence indicates that age disparities between young women and older men amplify relationship power imbalances already present in heterosexual relationships, increasing risk of transactional sex [<xref rid="pone.0159162.ref021" ref-type="bibr">21</xref>–<xref rid="pone.0159162.ref023" ref-type="bibr">23</xref>] and violence [<xref rid="pone.0159162.ref024" ref-type="bibr">24</xref>–<xref rid="pone.0159162.ref027" ref-type="bibr">27</xref>]. Alcohol use and associated risky behaviours may also be more common in age-disparate partnerships if middle-aged men and older men drink more frequently [<xref rid="pone.0159162.ref028" ref-type="bibr">28</xref>]. Where concurrency is concerned, a previous South African study found that men in age-disparate partnerships are more likely to report concurrent sexual partners, thereby connecting young women in age-disparate partnerships into broader sexual networks [<xref rid="pone.0159162.ref029" ref-type="bibr">29</xref>].</p><p>Given that previous studies on age-disparate partnerships have typically been conducted at either a national level [<xref rid="pone.0159162.ref016" ref-type="bibr">16</xref>–<xref rid="pone.0159162.ref018" ref-type="bibr">18</xref>,<xref rid="pone.0159162.ref029" ref-type="bibr">29</xref>], or within urban settings [<xref rid="pone.0159162.ref015" ref-type="bibr">15</xref>,<xref rid="pone.0159162.ref019" ref-type="bibr">19</xref>,<xref rid="pone.0159162.ref020" ref-type="bibr">20</xref>], another important gap in our understanding is the extent to which sexual behaviour in age-disparate partnerships differs between urban and rural contexts. Research on urban-rural differences in sexual behaviour suggests that individuals living in urban areas are more likely to have current regular sex partners and have had multiple partners [<xref rid="pone.0159162.ref030" ref-type="bibr">30</xref>–<xref rid="pone.0159162.ref032" ref-type="bibr">32</xref>], but are also more likely to use condoms [<xref rid="pone.0159162.ref031" ref-type="bibr">31</xref>,<xref rid="pone.0159162.ref033" ref-type="bibr">33</xref>–<xref rid="pone.0159162.ref036" ref-type="bibr">36</xref>]. Significantly greater access to condoms in urban areas [<xref rid="pone.0159162.ref036" ref-type="bibr">36</xref>] likely explains, in part, differentials in unprotected sex across regions. Differences in access to resources and in the cohesiveness of social networks between urban compared to rural areas also make heterogeneity in sexual behaviours in age-disparate partnerships across different geographical contexts entirely plausible.</p><p>This study expands on previous research by providing a comprehensive assessment of sexual behaviour within age-disparate partnerships using nationally representative data from South Africa. We examine both the sexual behaviour of the young women and sexual behaviour of the men in age-disparate partnerships with young women. This study further extends previous work through the examination of the urban and rural differences as a component of a multidimensional assessment of sexual behaviours within age-disparate partnerships.</p></sec><sec sec-type="materials|methods" id="sec006"><title>Methods</title><sec id="sec007"><title>Data</title><p>Cross-sectional data were analysed from the third National HIV Communication Survey (NCS) of South Africa, conducted in 2012 and representative of the population aged 16 to 55. The NCS used a multi-stage sampling approach with stratification by province, district and area type. Primary sampling units (2001 Census and 2007 Community Survey small areas) were selected based on probability proportional to size techniques. Households, followed by individuals, were randomly selected within primary sampling units [<xref rid="pone.0159162.ref037" ref-type="bibr">37</xref>]. The overall response rate was 83%.</p><p>The structured face-to-face interview collected data on the respondents’ three most recent sexual partnerships and whether each partnership was on-going. We created two data sets. The first comprising all the on-going partnerships reported by women aged 16 to 24. The second comprising all the on-going partnerships reported by <italic>male respondents</italic> in which the reported partner was a woman 16 to 24 years old. Given that these data include all on-going partnerships (i.e. including primary and secondary partners) of participants and that the data were nationally representative, both these data sets should represent all partnerships, at the time of the survey, involving 16–24 year old women. By considering all men who reported on-going partnerships with young women, this study was able to compare the risk characteristics of older men in age-disparate partnerships to those of younger men in age-similar partnerships with the same cohort of young women. This approach enabled us to consider data that cannot accurately be reported by young women about their male partners in surveys, namely transactional sex, alcohol use and concurrency.</p><p>We restricted our data to heterosexual partnerships (98.4% and 98.7% of partnerships reported by men and women respectively) in order to explore sexual risk behaviour within age-disparate partnerships between older men and young women. We further restricted our data to populations with particularly high HIV prevalence and infection rates by focusing our analysis on black African individuals [<xref rid="pone.0159162.ref038" ref-type="bibr">38</xref>]. Relatively little data were excluded under this restriction as the vast majority of the original study population relevant to our analysis comprised black African women (88%) and men (86%). Without data on the race of reported partners, we made the assumption that all heterosexual partners reported were black African given the extremely high rates of same-race partnerships within South Africa [<xref rid="pone.0159162.ref039" ref-type="bibr">39</xref>]. Under this assumption the data reported by black African men represent partnerships involving young black African women.</p></sec><sec id="sec008"><title>Ethics statement</title><p>The University of the Witwatersrand’s Human Research Ethics Committee and the Institutional Review Board of the Johns Hopkins Bloomberg School of Public Health granted ethical approval for the NCS, including all consent procedures. All participants provided written informed consent. The University of the Witwatersrand provided guidance on participation by children–that is, participants under the age of 18 years. For participants aged 16 and 17 years, both the child’s own consent and consent of a parent or guardian were required for participation in the study.</p></sec><sec id="sec009"><title>Measures</title><p>Our main independent variable of interest, age-disparate partnerships, identify partnerships with a 5-year or greater age disparity between young women and older men by calculating the difference between the participants’ age and their partner’s age. Four binary outcome variables measure sexual behaviour that could increase HIV infection risk for young women. Unprotected last sex identifies individuals who reported not using a condom the last time they had sex with their partner. The transactional sex variable measures whether women reported <italic>receiving</italic> gifts or money from their partner in the past year in exchange for sex and whether men reported <italic>giving</italic> their partner gifts or money in exchange for sex. Alcohol at last sex indicates respondents who reported drinking alcohol before they last had sex with their partner. The concurrency variable identifies men who reported two or more on-going partnerships (i.e. they expected to have sex again with the partners.) (See <xref ref-type="supplementary-material" rid="pone.0159162.s012">S1 Text</xref> for the wording of the survey questions.)</p><p>Individual-level factors that could potentially influence both the outcome measure and age-disparate partnerships included in the analysis as control variables were: age; being born outside of South Africa; education (categorised only as <xref ref-type="supplementary-material" rid="pone.0159162.s012">S1 Text</xref>). Partnership specific control variables included partnership type (married, cohabiting, casual, or other); partnership duration (less than a month, 2–6 months, 6–12 months, 1 year and more); and whether the respondents reported knowing their partner’s HIV status.</p></sec><sec id="sec010"><title>Analysis</title><p>First, individual-level data were used to describe the men and women in the samples. All subsequent analyses were conducted using the partnership as the unit of observation. We used standard differences in proportions tests to compare the prevalence of sexual behaviours in age-disparate and age-similar partnerships, with the analysis conducted separately by rural and urban setting. Our analysis of concurrency was restricted to partnerships reported by men because we are interested in how behaviour <italic>within</italic> a partnership impacts HIV risk for young women. At the partnership level, concurrency is not an additional risk factor for the person who has concurrent partners, because the risk comes simply from having multiple partners [<xref rid="pone.0159162.ref040" ref-type="bibr">40</xref>]. Concurrency is, however, a risk for the partner of the person who has concurrent relationships because those who have concurrent sexual partners may acquire HIV outside of the partnership and transmit HIV to their partner [<xref rid="pone.0159162.ref040" ref-type="bibr">40</xref>]. Therefore, young women are at a greater risk for HIV infection if the men they partner with have concurrent partners. The concurrency analysis accordingly assesses the proportion of men in partnerships with young women who reported an overlapping partner (of any age) at the time of the interview.</p><p>Multiple logistic regression models were created to assess the association between sexual behaviours and partnership type (age-similar v age-disparate), controlling for potential confounders. To investigate differences between rural and urban settings we reran our regression analysis and included an interaction term (created by multiplying an indicator of living in a rural setting by the age-disparate variable).</p><p>All analyses were adjusted to account for the complex study design (i.e. we used weighted data for all analyses and where relevant adjusted for stratified and clustered sampling) and non-response. By accounting for clustering using primary sampling units the analysis controls for all potential within-cluster error correlation, including potential correlation between partnership data [<xref rid="pone.0159162.ref041" ref-type="bibr">41</xref>]. This is important as some participants reported more than one partnership and an individual’s sexual behaviour across partnerships might be correlated. A priori we set p<0.1 to denote statistical significance given that the coefficients in the regression analysis would be estimated off relatively small numbers when disaggregating data by both partnership type and geographic location [<xref rid="pone.0159162.ref042" ref-type="bibr">42</xref>].</p><p>We conducted two sensitivity analyses. First, we assessed whether a different measure of unprotected sex (inconsistent condom use within partnerships) altered findings. Second, we tested whether using a continuous independent variable (years age difference between partners) resulted in different findings.</p></sec></sec><sec sec-type="results" id="sec011"><title>Results</title><p><xref ref-type="table" rid="pone.0159162.t001">Table 1</xref> displays descriptive statistics for the sample of 16 to 24 year old women (n = 790) and the sample of men who reported being in a partnership with 16 to 24 year old women (n = 801). The majority of the sample of women (77%) was between the ages of 20 and 24. Among the male sample, 53% were within the same age-bracket as the female sample (16–24), while a relatively low proportion of men were 30 years or older (13%). Just over half of each sample was from an urban setting. Young women reported 818 on-going partnerships, with 41% involving an age-disparate partner (5 years or older). Men reported 985 on-going partnerships involving 16 to 24 year old women, with 37% age-disparate. Differences in the proportion of age-disparate partnerships in urban and rural areas were small.</p><table-wrap id="pone.0159162.t001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0159162.t001</object-id><label>Table 1</label><caption><title>Sample characteristics.</title></caption><alternatives><graphic id="pone.0159162.t001g" xlink:href="pone.0159162.t001"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col></colgroup><thead><tr><th align="left" rowspan="1" colspan="1"></th><th align="center" rowspan="1" colspan="1">Women (16–24 years old)</th><th align="center" rowspan="1" colspan="1">Men in partnerships with 16–24 year old women</th></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1"><bold>Individual level data</bold></td><td align="center" rowspan="1" colspan="1">n = 790</td><td align="center" rowspan="1" colspan="1">n = 801</td></tr><tr><td align="left" rowspan="1" colspan="1">Age (mean)</td><td align="center" rowspan="1" colspan="1">21</td><td align="center" rowspan="1" colspan="1">24.6</td></tr><tr><td align="left" rowspan="1" colspan="1">Age categories</td><td align="center" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1"></td></tr><tr><td align="left" rowspan="1" colspan="1"> 16–19</td><td align="center" rowspan="1" colspan="1">23%</td><td align="center" rowspan="1" colspan="1">11%</td></tr><tr><td align="left" rowspan="1" colspan="1"> 20–24</td><td align="center" rowspan="1" colspan="1">77%</td><td align="center" rowspan="1" colspan="1">42%</td></tr><tr><td align="left" rowspan="1" colspan="1"> 25–29</td><td align="center" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">34%</td></tr><tr><td align="left" rowspan="1" colspan="1"> 30+</td><td align="center" rowspan="1" colspan="1">na</td><td align="center" rowspan="1" colspan="1">13%</td></tr><tr><td align="left" rowspan="1" colspan="1">Grade 12 complete</td><td align="center" rowspan="1" colspan="1">52%</td><td align="center" rowspan="1" colspan="1">55%</td></tr><tr><td align="left" rowspan="1" colspan="1">Not enough to eat (often/sometimes/rarely in past 12 months)</td><td align="center" rowspan="1" colspan="1">32%</td><td align="center" rowspan="1" colspan="1">33%</td></tr><tr><td align="left" rowspan="1" colspan="1">Employed</td><td align="center" rowspan="1" colspan="1">13%</td><td align="center" rowspan="1" colspan="1">13%</td></tr><tr><td align="left" rowspan="1" colspan="1">Urban</td><td align="center" rowspan="1" colspan="1">55%</td><td align="center" rowspan="1" colspan="1">52%</td></tr><tr><td align="left" rowspan="1" colspan="1">Know someone who died of AIDS</td><td align="center" rowspan="1" colspan="1">54%</td><td align="center" rowspan="1" colspan="1">55%</td></tr><tr><td align="left" rowspan="1" colspan="1">Had an HIV test</td><td align="center" rowspan="1" colspan="1">85%</td><td align="center" rowspan="1" colspan="1">57%</td></tr><tr><td align="left" rowspan="1" colspan="1">Good HIV knowledge (4 or 5 of 5 correct answers)</td><td align="center" rowspan="1" colspan="1">81%</td><td align="center" rowspan="1" colspan="1">80%</td></tr><tr><td align="left" rowspan="1" colspan="1"><bold>Partnership data</bold></td><td align="center" rowspan="1" colspan="1">n = 818</td><td align="center" rowspan="1" colspan="1">n = 985</td></tr><tr><td align="left" rowspan="1" colspan="1">Age disparate (5+ age-gap)</td><td align="center" rowspan="1" colspan="1">41%</td><td align="center" rowspan="1" colspan="1">37%</td></tr><tr><td align="left" rowspan="1" colspan="1">Partnership age difference 10+ years</td><td align="center" rowspan="1" colspan="1">7%</td><td align="center" rowspan="1" colspan="1">11%</td></tr><tr><td align="left" rowspan="1" colspan="1">Age disparate in urban areas</td><td align="center" rowspan="1" colspan="1">41%</td><td align="center" rowspan="1" colspan="1">40%</td></tr><tr><td align="left" rowspan="1" colspan="1">Age disparate in rural areas</td><td align="center" rowspan="1" colspan="1">40%</td><td align="center" rowspan="1" colspan="1">35%</td></tr><tr><td align="left" rowspan="1" colspan="1">Married</td><td align="center" rowspan="1" colspan="1">13%</td><td align="center" rowspan="1" colspan="1">10%</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="t001fn001"><p>Notes: All figures are adjusted to account for the complex study design and non-response.</p></fn></table-wrap-foot></table-wrap><sec id="sec012"><title>Sexual behaviours reported by women</title><p><xref ref-type="fig" rid="pone.0159162.g001">Fig 1</xref> displays sexual behaviours in age-disparate and age-similar partnerships as reported by women in both rural and urban settings. Condom use was less common in age-disparate partnerships. Unprotected sex was 11 percentage points higher in age-disparate partnerships in rural areas (p = 0.068) and 8 percentage points higher (p = 0.130) in urban areas. No obvious differences between partnership type and transactional sex or alcohol use were evident in either urban or rural settings.</p><fig id="pone.0159162.g001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0159162.g001</object-id><label>Fig 1</label><caption><title>Sexual behaviours reported by 16–24 year old women by partnership type (age-disparate v age-similar) and geographic (urban/rural) setting.</title><p>1a: unprotected last sex; 1b: received gifts for sex; 1c: alcohol and sex.</p></caption><graphic xlink:href="pone.0159162.g001"></graphic></fig><p>Multiple regression analysis of sexual behaviours reported by women (<xref ref-type="table" rid="pone.0159162.t002">Table 2</xref>) found that, after accounting for confounders, the patterns between partnership type and location of residence remained consistent with those in <xref ref-type="fig" rid="pone.0159162.g001">Fig 1</xref>. Panel A presents results from the models without the interaction term and Panel B the results from models including the age-disparate times rural interaction term. <xref ref-type="table" rid="pone.0159162.t002">Table 2</xref>, Panel A shows that the odds of unprotected sex (A1) were significantly higher in age-disparate partnerships (aOR: 1.51; p = 0.014; 95%CI: 1.09–2.11), but the associations between age-disparate partnerships and transactional sex (A2) and alcohol use (A3) were not statistically significant. See <xref ref-type="supplementary-material" rid="pone.0159162.s001">S1 Table</xref> for the full model.</p><table-wrap id="pone.0159162.t002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0159162.t002</object-id><label>Table 2</label><caption><title>Multiple logistic regression models of sexual behaviours within partnerships reported by 16 to 24 year old women.</title></caption><alternatives><graphic id="pone.0159162.t002g" xlink:href="pone.0159162.t002"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col></colgroup><thead><tr><th align="right" rowspan="1" colspan="1">Dependent variable:</th><th align="center" rowspan="1" colspan="1">Unprotected last sex</th><th align="center" rowspan="1" colspan="1">Received gifts for sex</th><th align="center" rowspan="1" colspan="1">Alcohol and sex</th></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1"><bold>Panel A</bold></td><td align="center" rowspan="1" colspan="1">A1</td><td align="center" rowspan="1" colspan="1">A2</td><td align="center" rowspan="1" colspan="1">A3</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate</td><td align="center" rowspan="1" colspan="1">1.51<xref ref-type="table-fn" rid="t002fn003">**</xref></td><td align="center" rowspan="1" colspan="1">1.20</td><td align="center" rowspan="1" colspan="1">1.30</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(1.09–2.11)</td><td align="center" rowspan="1" colspan="1">(0.65–2.21)</td><td align="center" rowspan="1" colspan="1">(0.74–2.29)</td></tr><tr><td align="left" rowspan="1" colspan="1">Rural</td><td align="center" rowspan="1" colspan="1">0.92</td><td align="center" rowspan="1" colspan="1">0.72</td><td align="center" rowspan="1" colspan="1">0.54</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.61–1.38)</td><td align="center" rowspan="1" colspan="1">(0.30–1.73)</td><td align="center" rowspan="1" colspan="1">(0.19–1.56)</td></tr><tr><td align="left" rowspan="1" colspan="1">Control variables</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td></tr><tr><td align="left" rowspan="1" colspan="1">n</td><td align="center" rowspan="1" colspan="1">816</td><td align="center" rowspan="1" colspan="1">785</td><td align="center" rowspan="1" colspan="1">780</td></tr><tr><td align="left" rowspan="1" colspan="1"><bold>Panel B</bold></td><td align="center" rowspan="1" colspan="1">B1</td><td align="center" rowspan="1" colspan="1">B2</td><td align="center" rowspan="1" colspan="1">B3</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate</td><td align="center" rowspan="1" colspan="1">1.44</td><td align="center" rowspan="1" colspan="1">1.20</td><td align="center" rowspan="1" colspan="1">1.02</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.93–2.24)</td><td align="center" rowspan="1" colspan="1">(0.53–2.73)</td><td align="center" rowspan="1" colspan="1">(0.54–1.95)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate<xref ref-type="table-fn" rid="t002fn004">*</xref>Rural</td><td align="center" rowspan="1" colspan="1">1.12</td><td align="center" rowspan="1" colspan="1">0.99</td><td align="center" rowspan="1" colspan="1">2.40</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.55–2.25)</td><td align="center" rowspan="1" colspan="1">(0.26–3.80)</td><td align="center" rowspan="1" colspan="1">(0.57–10.17)</td></tr><tr><td align="left" rowspan="1" colspan="1">Rural</td><td align="center" rowspan="1" colspan="1">0.88</td><td align="center" rowspan="1" colspan="1">0.72</td><td align="center" rowspan="1" colspan="1">0.35</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.55–1.40)</td><td align="center" rowspan="1" colspan="1">(0.25–2.11)</td><td align="center" rowspan="1" colspan="1">(0.07–1.62)</td></tr><tr><td align="left" rowspan="1" colspan="1">Control variables</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td></tr><tr><td align="left" rowspan="1" colspan="1">n</td><td align="center" rowspan="1" colspan="1">816</td><td align="center" rowspan="1" colspan="1">785</td><td align="center" rowspan="1" colspan="1">780</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="t002fn001"><p>Notes</p></fn><fn id="t002fn002"><p>*** p<0.01</p></fn><fn id="t002fn003"><p>** p<0.05</p></fn><fn id="t002fn004"><p>* p<0.1.</p></fn><fn id="t002fn005"><p>95% Confidence Intervals in brackets. Control variables include age, education, employment status, household wealth, HIV testing history, HIV knowledge, partnership type, partnership length and knowledge of partner’s HIV status (see <xref ref-type="supplementary-material" rid="pone.0159162.s001">S1 Table</xref> and <xref ref-type="supplementary-material" rid="pone.0159162.s002">S2 Table</xref> for the full models including coefficients for all control variables). All analyses are adjusted to account for the complex study design and non-response.</p></fn></table-wrap-foot></table-wrap><p>In Panel B, the coefficient on the interaction term (age-disparate*rural) was statistically insignificant in all models. These data indicate that the association between sexual behaviour reported by women and age-disparate partnerships did not differ significantly between rural and urban areas. (See <xref ref-type="supplementary-material" rid="pone.0159162.s002">S2 Table</xref> for the full model, and <xref ref-type="supplementary-material" rid="pone.0159162.s003">S3 Table</xref>, which shows similar results when using ordinary least squares regression models).</p></sec><sec id="sec013"><title>Sexual behaviours reported by men</title><p><xref ref-type="fig" rid="pone.0159162.g002">Fig 2</xref> presents the sexual behaviour data reported by men in partnerships with 16 to 24 year old women. <xref ref-type="fig" rid="pone.0159162.g002">Fig 2A</xref> shows, consistent with data reported by women in <xref ref-type="fig" rid="pone.0159162.g001">Fig 1</xref>, that age-disparate partnerships were more likely to involve unprotected sex than similar-aged partnerships. Differences in condom use by partnership type were similar in rural and urban areas: unprotected last sex was 21 percentage points higher in age-disparate partnerships in rural areas (p = 0.012) and 19 percentage points higher in age-disparate partnerships in urban areas (p<0.01). Transactional sex (<xref ref-type="fig" rid="pone.0159162.g002">Fig 2B</xref>) was only slightly higher in rural age-disparate partnerships (+2.9% points, p = 0.375), but significantly greater in age-disparate partnerships in urban settings (+15% points, p<0.01). The association between age-disparate partnerships and drinking alcohol before last sex (<xref ref-type="fig" rid="pone.0159162.g002">Fig 2C</xref>) varied between settings. In rural areas, a negative, but not statistically significant, relationship was found between age-disparate partnerships and drinking alcohol before last sex (-4% points, p = 0.170), while in urban areas men in age-disparate partnerships were significantly more likely to report this behaviour (+17% points, p<0.01). <xref ref-type="fig" rid="pone.0159162.g002">Fig 2D</xref> shows that a greater proportion of men in age-disparate partnerships with young women reported concurrency than men in similar-aged partnerships, but the differences were not statistically significant (rural: +6% points, p = 0.30; urban: +8% points, p = 0.14).</p><fig id="pone.0159162.g002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0159162.g002</object-id><label>Fig 2</label><caption><title>Sexual behaviours reported by men in partnerships with 16–24 year old women by partnership type (age-disparate v age-similar) and geographic (urban/rural) setting.</title><p>2a: unprotected last sex; 2b: gave gifts for sex; 2c: alcohol and sex; 2d: concurrency.</p></caption><graphic xlink:href="pone.0159162.g002"></graphic></fig><p><xref ref-type="table" rid="pone.0159162.t003">Table 3</xref> presents the results from multiple regression models of sexual behaviours of men within partnerships involving young women. Panel A presents results from the models without the interaction term and Panel B the results from models including the age-disparate times rural interaction term. The models in panel A show that age-disparate partnerships were associated with higher levels of unprotected last sex (A1: aOR:1.92; p<0.01; 95%CI: 1.31–2.81), transactional sex (A2: aOR:2.73; p<0.01; 95%CI: 1.64–4.56), alcohol use before sex (A3: aOR:1.6; p = 0.062; 95%CI: 0.98–2.61) and concurrency (A4: aOR: 1.39; p = 0.097; 95%CI: 0.94–2.07). Additional analysis found that the positive association between age-disparate partnerships and concurrency was particular large in partnerships involving younger (16 to 19 year old) women (aOR: 2.62; p<0.01; 95%CI: 1.29–5.3).</p><table-wrap id="pone.0159162.t003" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0159162.t003</object-id><label>Table 3</label><caption><title>Multiple logistic regression models of sexual behaviours reported by men in partnerships with 16 to 24 year old women.</title></caption><alternatives><graphic id="pone.0159162.t003g" xlink:href="pone.0159162.t003"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col></colgroup><thead><tr><th align="right" rowspan="1" colspan="1">Dependent variable:</th><th align="center" rowspan="1" colspan="1">Unprotected last sex</th><th align="center" rowspan="1" colspan="1">Gave gifts for sex</th><th align="center" rowspan="1" colspan="1">Alcohol and sex</th><th align="center" rowspan="1" colspan="1">Concurrency</th></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1"><bold>Panel A</bold></td><td align="center" rowspan="1" colspan="1">A1</td><td align="center" rowspan="1" colspan="1">A2</td><td align="center" rowspan="1" colspan="1">A3</td><td align="center" rowspan="1" colspan="1">A4</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate</td><td align="center" rowspan="1" colspan="1">1.92<xref ref-type="table-fn" rid="t003fn002">***</xref></td><td align="center" rowspan="1" colspan="1">2.73<xref ref-type="table-fn" rid="t003fn002">***</xref></td><td align="center" rowspan="1" colspan="1">1.60<xref ref-type="table-fn" rid="t003fn004">*</xref></td><td align="center" rowspan="1" colspan="1">1.39<xref ref-type="table-fn" rid="t003fn004">*</xref></td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(1.31–2.81)</td><td align="center" rowspan="1" colspan="1">(1.64–4.56)</td><td align="center" rowspan="1" colspan="1">(0.98–2.61)</td><td align="center" rowspan="1" colspan="1">(0.94–2.07)</td></tr><tr><td align="left" rowspan="1" colspan="1">Rural</td><td align="center" rowspan="1" colspan="1">1.03</td><td align="center" rowspan="1" colspan="1">0.90</td><td align="center" rowspan="1" colspan="1">0.51<xref ref-type="table-fn" rid="t003fn003">**</xref></td><td align="center" rowspan="1" colspan="1">0.52<xref ref-type="table-fn" rid="t003fn003">**</xref></td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.73–1.48)</td><td align="center" rowspan="1" colspan="1">(0.47–1.73)</td><td align="center" rowspan="1" colspan="1">(0.29–0.89)</td><td align="center" rowspan="1" colspan="1">(0.31–0.86)</td></tr><tr><td align="left" rowspan="1" colspan="1">Controls</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td></tr><tr><td align="left" rowspan="1" colspan="1">n</td><td align="center" rowspan="1" colspan="1">980</td><td align="center" rowspan="1" colspan="1">961</td><td align="center" rowspan="1" colspan="1">966</td><td align="center" rowspan="1" colspan="1">982</td></tr><tr><td align="left" rowspan="1" colspan="1"><bold>Panel B</bold></td><td align="center" rowspan="1" colspan="1">B1</td><td align="center" rowspan="1" colspan="1">B2</td><td align="center" rowspan="1" colspan="1">B3</td><td align="center" rowspan="1" colspan="1">B4</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td><td align="center" rowspan="1" colspan="1">aOR (95% CI)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate</td><td align="center" rowspan="1" colspan="1">1.70<xref ref-type="table-fn" rid="t003fn002">***</xref></td><td align="center" rowspan="1" colspan="1">4.28<xref ref-type="table-fn" rid="t003fn002">***</xref></td><td align="center" rowspan="1" colspan="1">2.38<xref ref-type="table-fn" rid="t003fn002">***</xref></td><td align="center" rowspan="1" colspan="1">1.28</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(1.15–2.52)</td><td align="center" rowspan="1" colspan="1">(2.25–8.13)</td><td align="center" rowspan="1" colspan="1">(1.28–4.46)</td><td align="center" rowspan="1" colspan="1">(0.80–2.07)</td></tr><tr><td align="left" rowspan="1" colspan="1">Age-disparate<xref ref-type="table-fn" rid="t003fn004">*</xref>Rural</td><td align="center" rowspan="1" colspan="1">1.29</td><td align="center" rowspan="1" colspan="1">0.34<xref ref-type="table-fn" rid="t003fn003">**</xref></td><td align="center" rowspan="1" colspan="1">0.27<xref ref-type="table-fn" rid="t003fn003">**</xref></td><td align="center" rowspan="1" colspan="1">1.22</td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.55–3.05)</td><td align="center" rowspan="1" colspan="1">(0.12–0.92)</td><td align="center" rowspan="1" colspan="1">(0.10–0.74)</td><td align="center" rowspan="1" colspan="1">(0.54–2.79)</td></tr><tr><td align="left" rowspan="1" colspan="1">Rural</td><td align="center" rowspan="1" colspan="1">0.94</td><td align="center" rowspan="1" colspan="1">1.55</td><td align="center" rowspan="1" colspan="1">0.84</td><td align="center" rowspan="1" colspan="1">0.48<xref ref-type="table-fn" rid="t003fn003">**</xref></td></tr><tr><td align="left" rowspan="1" colspan="1"></td><td align="center" rowspan="1" colspan="1">(0.60–1.48)</td><td align="center" rowspan="1" colspan="1">(0.67–3.60)</td><td align="center" rowspan="1" colspan="1">(0.46–1.53)</td><td align="center" rowspan="1" colspan="1">(0.25–0.90)</td></tr><tr><td align="left" rowspan="1" colspan="1">Controls</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td><td align="center" rowspan="1" colspan="1">Yes</td></tr><tr><td align="left" rowspan="1" colspan="1">n</td><td align="center" rowspan="1" colspan="1">980</td><td align="center" rowspan="1" colspan="1">961</td><td align="center" rowspan="1" colspan="1">966</td><td align="center" rowspan="1" colspan="1">982</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="t003fn001"><p>Notes</p></fn><fn id="t003fn002"><p>*** p<0.01</p></fn><fn id="t003fn003"><p>** p<0.05</p></fn><fn id="t003fn004"><p>* p<0.1.</p></fn><fn id="t003fn005"><p>95% Confidence Intervals in brackets. Control variables include age, education, employment status, household wealth, HIV testing history, HIV knowledge, partnership type, partnership length and knowledge of partner’s HIV status (see <xref ref-type="supplementary-material" rid="pone.0159162.s004">S4 Table</xref> and <xref ref-type="supplementary-material" rid="pone.0159162.s005">S5 Table</xref> for the full models including coefficients for all control variables). All analyses are adjusted to account for the complex study design and non-response.</p></fn></table-wrap-foot></table-wrap><p>The coefficients on the interaction terms in models B1 and B4 (<xref ref-type="table" rid="pone.0159162.t003">Table 3</xref>, Panel B) are close to one and not statistically significant, indicating no differences between rural and urban areas in the association between age-disparate partnerships and either condom use or concurrent sexual partnerships, respectively. In contrast, large urban-rural differences were found regarding the association between age-disparate partnerships and transactional sex and alcohol use. The coefficient on the interaction term indicated that the association between age-disparate partnerships and both transactional sex (B2: aOR: 0.34; p<0.05; 95%CI: 0.12–0.92) and drinking before sex (B3: aOR: 0.27; p<0.05; 95%CI: 0.10–0.74) was significantly weaker in rural areas. Results from this analysis were substantively similar when ordinary least square regression models were used instead of logistic regression models: see <xref ref-type="supplementary-material" rid="pone.0159162.s006">S6 Table</xref>). Consistent with these findings, additional analysis (see <xref ref-type="supplementary-material" rid="pone.0159162.s007">S7 Table</xref>) found that the association between age-disparate partnerships and transactional sex was highly significant <italic>within</italic> urban areas (aOR: 4.14; p<0.01; 95%CI: 2.03–8.46), but not significantly different <italic>within</italic> rural areas (aOR: 1.04; p = 0.92; 95%CI: 0.42–2.58). Similarly, men in age-disparate partnerships within urban areas were more likely to have consumed alcohol before sex than men in similar-aged partnerships (aOR: 2.24; p<0.012; 95%CI: 1.20–4.19), while this was not the case in rural areas (aOR: 0.8; p = 0.579; 95%CI: 0.35–1.81).</p><p>Sensitivity analyses (see <xref ref-type="supplementary-material" rid="pone.0159162.s008">S8 Table</xref> and <xref ref-type="supplementary-material" rid="pone.0159162.s009">S9 Table</xref>) found that age-disparate partnerships were also associated with inconsistent condom use during the partnership as reported by women (aOR: 1.42; p = 0.034; 95%CI: 1.03–1.98) and by men in partnerships with 16–24 year old women (aOR: 1.81; p<0.01; 95%CI: 1.32–2.47). In addition, all statistically significant and positive associations between our binary measure of age-disparate partnerships and risky sexual behaviour remained statistically significant and positive in models using a continuous independent variable (years age difference between partners; see <xref ref-type="supplementary-material" rid="pone.0159162.s010">S10 Table</xref> and <xref ref-type="supplementary-material" rid="pone.0159162.s011">S11 Table</xref>).</p></sec></sec><sec sec-type="conclusions" id="sec014"><title>Discussion</title><p>The relationship between age-disparate partnerships and HIV infection risk among young women is complex and not fully understood. This study expands on previous research by assessing a broad range of sexual behaviours within age disparate partnerships as reported by both young black African women and the black African men in partnerships with young women.</p><p>Consistent with previous studies from South Africa [<xref rid="pone.0159162.ref010" ref-type="bibr">10</xref>], age-disparate partnerships were common among young women, with a little over a third of young women’s on-going partnerships involving a male partner five or more years older. This result was consistent in the partnership data reported by 16 to 24 year old women and the data reported by male respondents in partnerships with 16 to 24 year old women, which instils confidence that both samples are representative of age-disparate partnerships involving young women.</p><p>Overall, our findings show that age-disparate partnerships are associated with behavioural characteristics which could increase the risk of HIV infection for young women. Consistent with previous studies [<xref rid="pone.0159162.ref015" ref-type="bibr">15</xref>–<xref rid="pone.0159162.ref020" ref-type="bibr">20</xref>], condoms were found less likely to be used in age-disparate compared to age-similar partnerships. This finding was substantively similar in partnership data collected among young women and among men in partnerships with young women. Since gender biases have been observed in self-reporting of sexual behaviour [<xref rid="pone.0159162.ref043" ref-type="bibr">43</xref>], our findings provide strong evidence that age-disparate partnerships involve more unprotected sex.</p><p>In line with qualitative research that indicates transactional sex is a motivating factor for age-disparate partnerships involving young women [<xref rid="pone.0159162.ref014" ref-type="bibr">14</xref>,<xref rid="pone.0159162.ref044" ref-type="bibr">44</xref>,<xref rid="pone.0159162.ref045" ref-type="bibr">45</xref>], we found a strong, positive association between age-disparate partnerships and transactional sex, as reported by men in partnerships with young women. While a greater proportion of age-disparate partnerships in our data reported by men were classified as spousal relationships (21% of age-disparate, 7% of age-similar), as has been found elsewhere in South Africa [<xref rid="pone.0159162.ref046" ref-type="bibr">46</xref>], only a small proportion of all partnerships involved married partners and the association between age-disparate partnerships and transactional sex remained robust after controlling for marital status. However, despite evidence that transactional sex–motivated both by subsistence needs and conspicuous consumption–plays a role in age-disparate relationship formation in urban [<xref rid="pone.0159162.ref023" ref-type="bibr">23</xref>,<xref rid="pone.0159162.ref024" ref-type="bibr">24</xref>,<xref rid="pone.0159162.ref047" ref-type="bibr">47</xref>–<xref rid="pone.0159162.ref049" ref-type="bibr">49</xref>], as well as in rural settings in southern Africa [<xref rid="pone.0159162.ref022" ref-type="bibr">22</xref>,<xref rid="pone.0159162.ref044" ref-type="bibr">44</xref>,<xref rid="pone.0159162.ref050" ref-type="bibr">50</xref>], our results indicate that age-disparate partnerships are more likely to involve transactional sex only in urban areas.</p><p>The explanation for this geographic variation is unclear. Such variation may reflect differences between rural and urban areas in gendered material inequity, which has been established as a key driver of transactional sex [<xref rid="pone.0159162.ref025" ref-type="bibr">25</xref>,<xref rid="pone.0159162.ref051" ref-type="bibr">51</xref>]. Such variation could also be due to urbanisation which has both reshaped masculinities and sexual practices [<xref rid="pone.0159162.ref051" ref-type="bibr">51</xref>] and created differentials between rural and urban areas in the degree to which young women are subjected to traditions that guide relations between generations and between men and women [<xref rid="pone.0159162.ref025" ref-type="bibr">25</xref>]. Another potential explanation is that this variation is a confluence of the more prevalent practice of multiple sexual partnering found in urban than rural areas [<xref rid="pone.0159162.ref030" ref-type="bibr">30</xref>–<xref rid="pone.0159162.ref032" ref-type="bibr">32</xref>], which is also reflected in our results, and the positive association between transactional sex and multiple sexual partners [<xref rid="pone.0159162.ref052" ref-type="bibr">52</xref>,<xref rid="pone.0159162.ref053" ref-type="bibr">53</xref>].</p><p>Regardless of the mechanism underlying the geographic variation, our findings suggest greater sexual risk for young women in age-disparate partnerships in urban areas as transactional sex has been linked to high risk behaviours including unprotected sex [<xref rid="pone.0159162.ref014" ref-type="bibr">14</xref>] and anal sex [<xref rid="pone.0159162.ref054" ref-type="bibr">54</xref>,<xref rid="pone.0159162.ref055" ref-type="bibr">55</xref>], as well as intimate-partner violence [<xref rid="pone.0159162.ref056" ref-type="bibr">56</xref>–<xref rid="pone.0159162.ref058" ref-type="bibr">58</xref>]. Gender differences in perceptions about motivations and intentions within partnerships in South Africa [<xref rid="pone.0159162.ref056" ref-type="bibr">56</xref>,<xref rid="pone.0159162.ref059" ref-type="bibr">59</xref>,<xref rid="pone.0159162.ref060" ref-type="bibr">60</xref>] align with our findings that men are more likely to perceive a transactional element in partnerships than women. HIV infection risk may be especially high in age-disparate partnerships in cases where men perceive there to be a transactional element to the partnership while women do not. For instance, young women are less likely to use condoms with men from whom they expect monogamy and commitment [<xref rid="pone.0159162.ref061" ref-type="bibr">61</xref>,<xref rid="pone.0159162.ref062" ref-type="bibr">62</xref>]. Further research is required to explore how gendered perspectives of transactional partnerships influence HIV risk.</p><p>Alcohol use is also associated with high-risk sexual behaviours [<xref rid="pone.0159162.ref063" ref-type="bibr">63</xref>]. We found that men in partnerships with young women in urban settings were significantly more likely to drink alcohol before sex when the partnerships were age-disparate. Gender differences in risk associated with alcohol use have been reported elsewhere in southern Africa, with a woman’s risk often associated with her male partner’s consumption of alcohol [<xref rid="pone.0159162.ref064" ref-type="bibr">64</xref>]. Our results suggest that this risk is greater for women in urban areas in age-disparate partnerships.</p><p>Building on a nascent literature [<xref rid="pone.0159162.ref029" ref-type="bibr">29</xref>], our results show that concurrency among men may be an additional factor associated with age-disparate partnerships that increases young women’s HIV risk. Our findings indicate that young women with age-disparate male partners are more likely to be connected to a broader sexual network, and therefore more likely to acquire HIV, than women in age-similar partnerships. While the strength of this association was relatively weak (only borderline significant at the 10% level) among all partnerships involving 16–24 year old women–indicating the need for further research to tests this relationship–concurrency was identified as a particularly strong risk factor associated with age-disparate partnerships among adolescent (16 to 19 year old) women. Currently, theories on how age-disparate partnerships increase HIV risk for young women are closely tied to the statistical likelihood that older partners are more likely to be HIV positive than younger partners [<xref rid="pone.0159162.ref038" ref-type="bibr">38</xref>,<xref rid="pone.0159162.ref065" ref-type="bibr">65</xref>]. As a result of concurrency among men, age-disparate partnerships could also increase a young women’s HIV risk even when her partner is HIV-negative at the start of the partnership.</p><p>Results from this study have several policy and research implications. Our findings provide the first evidence indicating that the HIV infection risk for young women associated with age-disparate partnerships may be greater in urban than in rural settings. Explanations for differences in sexual behaviour in age-disparate partnerships between urban and rural areas should be explored. Our evidence supports interventions to reduce the HIV infection risk that age-disparate partnerships pose to young women, and points towards such interventions being particularly important in urban areas. Our finding that age-disparate partnerships are associated with greater sexual risk, even in rural areas, does not support the theory that careful selection of older, lower-risk male partners may mitigate the HIV risk associated with age-disparate partnerships. Alternative theories for the lack of association between age-disparate partnerships and HIV risk found in some studies [<xref rid="pone.0159162.ref002" ref-type="bibr">2</xref>,<xref rid="pone.0159162.ref006" ref-type="bibr">6</xref>] should be explored. For example, differential uptake of antiretroviral therapy by age, with older men living with HIV more likely to be on ART [<xref rid="pone.0159162.ref038" ref-type="bibr">38</xref>], and less likely to be lost to follow-up after HIV diagnosis compared to younger men [<xref rid="pone.0159162.ref066" ref-type="bibr">66</xref>], may mitigate the HIV infection risk that age-disparate partnerships pose for young women.</p><p>Limitations in our study include the potential for misreporting of partnerships [<xref rid="pone.0159162.ref067" ref-type="bibr">67</xref>], and the potential for error in reporting of partner’s age [<xref rid="pone.0159162.ref068" ref-type="bibr">68</xref>]. Social desirability bias may have influenced self-reported measures of sexual behaviour. Our measure of transactional sex may not fully capture transactional elements within partnerships, which can be more nuanced than the direct exchange of money and gifts for sex. For example, a study found that one in three U.S. women have had economically motivated relationships, yet only one in ten of those women reported exchanging sex for money [<xref rid="pone.0159162.ref069" ref-type="bibr">69</xref>]. Furthermore, compared to our results, higher levels of transactional sex were found in rural South Africa in a study using a multidimensional measurement of transactional sex [<xref rid="pone.0159162.ref070" ref-type="bibr">70</xref>]. In addition, our data is from a household survey and may not accurately represent migrant workers and mobile populations. Finally, our results may be generalized to partnerships of young black African women, but not to other population groups within South Africa.</p><p>In conclusion, we found that young women’s age-disparate partnerships in both urban and rural settings are characterised by greater sexual risk behaviour. This is especially the case in urban areas. Results from this study support the hypothesis that age-disparate partnerships increase HIV infection risk for young women and suggest that interventions to reduce this risk are warranted. Future research and policy development should be cognisant that age-disparate partnerships in urban areas may involve additional elements of risk for young women.</p></sec><sec sec-type="supplementary-material" id="sec015"><title>Supporting Information</title><supplementary-material content-type="local-data" id="pone.0159162.s001"><label>S1 Table</label><caption><title>Full multivariable logistic regression results for the models presented in <xref ref-type="table" rid="pone.0159162.t002">Table 2</xref>, Panel A.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s001.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s002"><label>S2 Table</label><caption><title>Full multivariable logistic regression results for the models presented in <xref ref-type="table" rid="pone.0159162.t002">Table 2</xref>, Panel B.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s002.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s003"><label>S3 Table</label><caption><title>Ordinary Least Squares regression models of sexual behaviours in partnerships reported by 16 to 24 year old women, with the inclusion of the interaction term ‘age-disparate*rural’.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s003.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s004"><label>S4 Table</label><caption><title>Full multivariable logistic regression results for the models presented in <xref ref-type="table" rid="pone.0159162.t003">Table 3</xref>, Panel A.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s004.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s005"><label>S5 Table</label><caption><title>Full multivariable logistic regression results for the models presented in <xref ref-type="table" rid="pone.0159162.t003">Table 3</xref>, Panel B.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s005.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s006"><label>S6 Table</label><caption><title>Ordinary Least Squares regression models of sexual behaviours reported by men in partnerships with 16 to 24 year old women, with the inclusion of the interaction term ‘age-disparate*rural’.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s006.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s007"><label>S7 Table</label><caption><title>Multivariable logistic regression models of transactional sex and alcohol consumption <italic>within</italic> rural and urban areas as reported by men in partnership with 16–24 year old women.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s007.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s008"><label>S8 Table</label><caption><title>Multivariable logistic regression models of inconsistent condom use within partnerships reported by 16 to 24 year old women.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s008.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s009"><label>S9 Table</label><caption><title>Multivariable logistic regression models of inconsistent condom use reported by men in partnerships with 16 to 24 year old women.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s009.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s010"><label>S10 Table</label><caption><title>Multivariable logistic regression models of sexual behaviours within partnerships reported by 16 to 24 year old women (independent variable = years age difference).</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s010.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s011"><label>S11 Table</label><caption><title>Multivariable logistic regression models of sexual behaviours reported by men in partnerships with 16 to 24 year old women (independent variable = years age difference).</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s011.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0159162.s012"><label>S1 Text</label><caption><title>Relevant questions for our analysis from the Third National Communication Survey, 2012.</title><p>(DOCX)</p></caption><media xlink:href="pone.0159162.s012.docx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material></sec></body><back><ack><p>The authors thank Atheendar Venkataramani and David Maughan Brown for helpful comments and suggestions on previous versions of this manuscript. The data used in this paper are from the Third National HIV Communication Survey (NCS). The NCS is a collaborative survey undertaken by Johns Hopkins Health and Education in South Africa (JHHESA), loveLife and Soul City. The survey was managed by Health and Development Africa (HDA). The Johns Hopkins Bloomberg School of Public Health Center for Communication Programs (JHU-CCP) provided technical support and oversight at all stages of the study. Data were gathered by Freshly Ground Insights (FGI). The NCS was funded by the Department of Health, the United States Agency for International Development (USAID) through the President’s Emergency Plan for AIDS Relief (PEPFAR) and the Global Fund.</p></ack><ref-list><title>References</title><ref id="pone.0159162.ref001"><label>1</label><mixed-citation publication-type="book"><collab>UNAIDS</collab>. <source>Global Report: UNAIDS Report on the Global AIDS Epidemic 2013</source>. <publisher-loc>Geneva</publisher-loc>: <publisher-name>UNAIDS</publisher-name>; <year>2013</year> Available: <ext-link ext-link-type="uri" xlink:href="http://www.unaids.org/sites/default/files/media_asset/UNAIDS_Global_Report_2013_en_1.pdf">http://www.unaids.org/sites/default/files/media_asset/UNAIDS_Global_Report_2013_en_1.pdf</ext-link></mixed-citation></ref><ref id="pone.0159162.ref002"><label>2</label><mixed-citation publication-type="journal"><name><surname>Harling</surname><given-names>G</given-names></name>, <name><surname>Newell</surname><given-names>M-L</given-names></name>, <name><surname>Tanser</surname><given-names>F</given-names></name>, <name><surname>Kawachi</surname><given-names>I</given-names></name>, <name><surname>Subramanian</surname><given-names>SV</given-names></name>, <name><surname>Barnighausen</surname><given-names>T</given-names></name>. <article-title>Do Age-Disparate Relationships Drive HIV Incidence in Young Women? Evidence from a Population Cohort in Rural KwaZulu-Natal, South Africa</article-title>. <source>J Acquir Immune Defic Syndr</source>. <year>2014</year>;<volume>66</volume>: <fpage>433</fpage>–<lpage>451</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref003"><label>3</label><mixed-citation publication-type="other">KwaZulu-Natal Department of Health. Sugar Daddy Campaign. 2012. Available: <ext-link ext-link-type="uri" xlink:href="http://www.kznhealth.gov.za/sugardaddy.htm">http://www.kznhealth.gov.za/sugardaddy.htm</ext-link>.</mixed-citation></ref><ref id="pone.0159162.ref004"><label>4</label><mixed-citation publication-type="book"><name><surname>Hope</surname><given-names>R</given-names></name>. <source>Addressing Cross-Generational Sex: a Desk Review of Research and Programs</source>. <publisher-loc>Washington, DC</publisher-loc>: <publisher-name>Population Reference Bureau</publisher-name>; <year>2007</year> Available: <ext-link ext-link-type="uri" xlink:href="http://www.prb.org/Publications/Reports/2007/addressingcrossgenerationalsex.aspx">http://www.prb.org/Publications/Reports/2007/addressingcrossgenerationalsex.aspx</ext-link></mixed-citation></ref><ref id="pone.0159162.ref005"><label>5</label><mixed-citation publication-type="other">PSI. Cross-generational sex. 2014. Available at: <ext-link ext-link-type="uri" xlink:href="http://www.psi.org/our-work/healthy-lives/interventions/cross-generational-sex">http://www.psi.org/our-work/healthy-lives/interventions/cross-generational-sex</ext-link>.</mixed-citation></ref><ref id="pone.0159162.ref006"><label>6</label><mixed-citation publication-type="journal"><name><surname>Balkus</surname><given-names>JE</given-names></name>, <name><surname>Nair</surname><given-names>G</given-names></name>, <name><surname>Montgomery</surname><given-names>ET</given-names></name>, <name><surname>Mishra</surname><given-names>A</given-names></name>, <name><surname>Palanee-Phillips</surname><given-names>T</given-names></name>, <name><surname>Ramjee</surname><given-names>G</given-names></name>, <etal>et al</etal><article-title>Age-Disparate Partnerships and Risk of HIV-1 Acquisition Among South African Women Participating in the VOICE Trial</article-title>. <source>J Acquir Immune Defic Syndr</source>. <year>2015</year>;<volume>70</volume>: <fpage>212</fpage>–<lpage>217</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAI.0000000000000715">10.1097/QAI.0000000000000715</ext-link></comment><pub-id pub-id-type="pmid">26049280</pub-id></mixed-citation></ref><ref id="pone.0159162.ref007"><label>7</label><mixed-citation publication-type="journal"><name><surname>Gregson</surname><given-names>S</given-names></name>, <name><surname>Nyamukapa</surname><given-names>C</given-names></name>, <name><surname>Garnett</surname><given-names>G</given-names></name>, <name><surname>Mason</surname><given-names>P</given-names></name>, <name><surname>Zhuwau</surname><given-names>T</given-names></name>, <name><surname>Caraël</surname><given-names>M</given-names></name>, <etal>et al</etal><article-title>Sexual mixing patterns and sex-differentials in teenage exposure to HIV infection in rural Zimbabwe</article-title>. <source>Lancet</source>. <year>2002</year>;<volume>359</volume>: <fpage>1896</fpage>–<lpage>1903</lpage>. <pub-id pub-id-type="pmid">12057552</pub-id></mixed-citation></ref><ref id="pone.0159162.ref008"><label>8</label><mixed-citation publication-type="journal"><name><surname>Katz</surname><given-names>I</given-names></name>, <name><surname>Low-Beer</surname><given-names>D</given-names></name>. <article-title>Why Has HIV Stabilized in South Africa, Yet Not Declined Further? Age and Sexual Behavior Patterns Among Youth</article-title>. <source>Sex Transm Dis</source>. <year>2008</year>;<volume>35</volume>(<issue>10</issue>): <fpage>837</fpage>–<lpage>842</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/OLQ.0b013e31817c0be5">10.1097/OLQ.0b013e31817c0be5</ext-link></comment><pub-id pub-id-type="pmid">18607312</pub-id></mixed-citation></ref><ref id="pone.0159162.ref009"><label>9</label><mixed-citation publication-type="journal"><name><surname>Kelly</surname><given-names>RJ</given-names></name>, <name><surname>Gray</surname><given-names>RH</given-names></name>, <name><surname>Sewankambo</surname><given-names>NK</given-names></name>, <name><surname>Serwadda</surname><given-names>D</given-names></name>, <name><surname>Wabwire-Mangen</surname><given-names>F</given-names></name>, <name><surname>Lutalo</surname><given-names>T</given-names></name>, <etal>et al</etal><article-title>Age differences in sexual partners and risk of HIV-1 infection in rural Uganda</article-title>. <source>J Acquir Immune Defic Syndr</source>. <year>2003</year>;<volume>32</volume>: <fpage>446</fpage>–<lpage>451</lpage>. <pub-id pub-id-type="pmid">12640205</pub-id></mixed-citation></ref><ref id="pone.0159162.ref010"><label>10</label><mixed-citation publication-type="journal"><name><surname>Pettifor</surname><given-names>A</given-names></name>, <name><surname>Rees</surname><given-names>H</given-names></name>, <name><surname>Kleinschmidt</surname><given-names>I</given-names></name>, <name><surname>Steffenson</surname><given-names>A</given-names></name>, <name><surname>MacPhail</surname><given-names>C</given-names></name>, <name><surname>Hlongwa-Madikizela</surname><given-names>L</given-names></name>, <etal>et al</etal><article-title>Young people's sexual health in South Africa: HIV prevalence and sexual behaviors from a nationally representative household survey</article-title>. <source>AIDS</source>. <year>2005</year>;<volume>19</volume>: <fpage>1525</fpage>–<lpage>1534</lpage>. <pub-id pub-id-type="pmid">16135907</pub-id></mixed-citation></ref><ref id="pone.0159162.ref011"><label>11</label><mixed-citation publication-type="journal"><name><surname>Chapman</surname><given-names>R</given-names></name>, <name><surname>White</surname><given-names>RG</given-names></name>, <name><surname>Shafer</surname><given-names>LA</given-names></name>, <name><surname>Pettifor</surname><given-names>A</given-names></name>, <name><surname>Mugurungi</surname><given-names>O</given-names></name>, <name><surname>Ross</surname><given-names>D</given-names></name>, <etal>et al</etal><article-title>Do behavioural differences help to explain variations in HIV prevalence in adolescents in sub‐Saharan Africa?</article-title><source>Trop Med Int Health</source>. <year>2010</year>;<volume>15</volume>: <fpage>554</fpage>–<lpage>566</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1111/j.1365-3156.2010.02483.x">10.1111/j.1365-3156.2010.02483.x</ext-link></comment><pub-id pub-id-type="pmid">20345559</pub-id></mixed-citation></ref><ref id="pone.0159162.ref012"><label>12</label><mixed-citation publication-type="journal"><name><surname>Baird</surname><given-names>SJ</given-names></name>, <name><surname>Garfein</surname><given-names>RS</given-names></name>, <name><surname>McIntosh</surname><given-names>CT</given-names></name>, <name><surname>Ozler</surname><given-names>B</given-names></name>. <article-title>Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: a cluster randomised trial</article-title>. <source>Lancet</source>. <year>2012</year>;<volume>379</volume>: <fpage>1320</fpage>–<lpage>1329</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/S0140-6736(11)61709-1">10.1016/S0140-6736(11)61709-1</ext-link></comment><pub-id pub-id-type="pmid">22341825</pub-id></mixed-citation></ref><ref id="pone.0159162.ref013"><label>13</label><mixed-citation publication-type="journal"><name><surname>Dupas</surname><given-names>P</given-names></name>. <article-title>Do teenagers respond to HIV risk information? Evidence from a field experiment in Kenya</article-title>. <source>American Economic Journal: Applied Economics</source>. <year>2009</year>;<volume>3</volume>: <fpage>1</fpage>–<lpage>34</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref014"><label>14</label><mixed-citation publication-type="journal"><name><surname>Luke</surname><given-names>N</given-names></name>. <article-title>Age and economic asymmetries in the sexual relationships of adolescent girls in sub-Saharan Africa</article-title>. <source>Stud Family Plann</source>. <year>2003</year>;<volume>34</volume>: <fpage>67</fpage>–<lpage>86</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref015"><label>15</label><mixed-citation publication-type="journal"><name><surname>Luke</surname><given-names>N</given-names></name>. <article-title>Confronting the “sugar daddy” stereotype: age and economic asymmetries and risky sexual behavior in urban Kenya</article-title>. <source>Int Fam Plan Perspect</source>. <year>2005</year>;<volume>31</volume>: <fpage>6</fpage>–<lpage>14</lpage>. <pub-id pub-id-type="pmid">15888404</pub-id></mixed-citation></ref><ref id="pone.0159162.ref016"><label>16</label><mixed-citation publication-type="journal"><name><surname>Bankole</surname><given-names>A</given-names></name>, <name><surname>Ahmed</surname><given-names>FH</given-names></name>, <name><surname>Neema</surname><given-names>S</given-names></name>, <name><surname>Ouedraogo</surname><given-names>C</given-names></name>, <name><surname>Konyani</surname><given-names>S</given-names></name>. <article-title>Knowledge of correct condom use and consistency of use among adolescents in four countries in sub-Saharan Africa</article-title>. <source>African Journal of Reproductive Health</source>. <year>2007</year>;<volume>11</volume>: <fpage>197</fpage>–<lpage>220</lpage>. <pub-id pub-id-type="pmid">18458741</pub-id></mixed-citation></ref><ref id="pone.0159162.ref017"><label>17</label><mixed-citation publication-type="journal"><name><surname>Langeni</surname><given-names>T</given-names></name>. <article-title>Contextual factors associated with treatment-seeking and higher-risk sexual behaviour in Botswana among men with symptoms of sexually transmitted infections</article-title>. <source>Afr J AIDS Res</source>. <year>2007</year>;<volume>6</volume>: <fpage>261</fpage>–<lpage>269</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.2989/16085900709490422">10.2989/16085900709490422</ext-link></comment><pub-id pub-id-type="pmid">25866172</pub-id></mixed-citation></ref><ref id="pone.0159162.ref018"><label>18</label><mixed-citation publication-type="journal"><name><surname>Malema</surname><given-names>BW</given-names></name>. <article-title>Determinants of Condom use in Botswana: An empirical Investigation of the Role of Gender</article-title>. <source>Botswana Journal of Economics</source>. <year>2012</year>;<volume>10</volume>: <fpage>59</fpage>–<lpage>78</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref019"><label>19</label><mixed-citation publication-type="journal"><name><surname>Beauclair</surname><given-names>R</given-names></name>, <name><surname>Kassanjee</surname><given-names>R</given-names></name>, <name><surname>Temmerman</surname><given-names>M</given-names></name>, <name><surname>Welte</surname><given-names>A</given-names></name>, <name><surname>Delva</surname><given-names>W</given-names></name>. <article-title>Age-disparate relationships and implications for STI transmission among young adults in Cape Town, South Africa</article-title>. <source>Eur J Contracept Reprod Health Care</source>. <year>2012</year>;<volume>17</volume>(<issue>1</issue>): <fpage>30</fpage>–<lpage>39</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.3109/13625187.2011.644841">10.3109/13625187.2011.644841</ext-link></comment><pub-id pub-id-type="pmid">22239263</pub-id></mixed-citation></ref><ref id="pone.0159162.ref020"><label>20</label><mixed-citation publication-type="journal"><name><surname>Volpe</surname><given-names>E</given-names></name>, <name><surname>Hardie</surname><given-names>T</given-names></name>, <name><surname>Cerulli</surname><given-names>C</given-names></name>, <name><surname>Sommers</surname><given-names>M</given-names></name>, <name><surname>Morrison-Beedy</surname><given-names>M</given-names></name>. <article-title>What’s Age Got to Do With It? Partner Age Difference, Power, Intimate Partner Violence, and Sexual Risk in Urban Adolescents</article-title>. <source>J Interpers Violence</source>. <year>2013</year>;<volume>28</volume>: <fpage>2068</fpage>–<lpage>2087</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1177/0886260512471082">10.1177/0886260512471082</ext-link></comment><pub-id pub-id-type="pmid">23345572</pub-id></mixed-citation></ref><ref id="pone.0159162.ref021"><label>21</label><mixed-citation publication-type="journal"><name><surname>Leclerc-Madlala</surname><given-names>S</given-names></name><article-title>. Transactional sex and the pursuit of modernity</article-title>. <source>Social Dynamics</source>. <year>2003</year>;<volume>29</volume>: <fpage>213</fpage>–<lpage>233</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref022"><label>22</label><mixed-citation publication-type="journal"><name><surname>Wamoyi</surname><given-names>J</given-names></name>, <name><surname>Fenwick</surname><given-names>A</given-names></name>, <name><surname>Urassa</surname><given-names>M</given-names></name>, <name><surname>Zaba</surname><given-names>B</given-names></name>. <article-title>“‘Women’s Bodies are Shops”‘: Beliefs About Transactional Sex and Implications for Understanding Gender Power and HIV Prevention in Tanzania</article-title>. <source>Arch Sex Behav</source>. <year>2011</year>; <volume>40</volume>:<fpage>5</fpage>–<lpage>15</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1007/s10508-010-9646-8">10.1007/s10508-010-9646-8</ext-link></comment><pub-id pub-id-type="pmid">20652390</pub-id></mixed-citation></ref><ref id="pone.0159162.ref023"><label>23</label><mixed-citation publication-type="journal"><name><surname>Zembe</surname><given-names>Y</given-names></name>, <name><surname>Townsend</surname><given-names>L</given-names></name>, <name><surname>Thorson</surname><given-names>A</given-names></name>, <name><surname>Ekström</surname><given-names>AM</given-names></name>. <article-title>“Money talks, bullshit walks” interrogating notions of consumption and survival sex among young women engaging in transactional sex in post-apartheid South Africa: a qualitative enquiry</article-title>. <source>Global Health</source>. <year>2013</year>;<volume>9</volume>: <fpage>28</fpage><comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1186/1744-8603-9-28">10.1186/1744-8603-9-28</ext-link></comment><pub-id pub-id-type="pmid">23866170</pub-id></mixed-citation></ref><ref id="pone.0159162.ref024"><label>24</label><mixed-citation publication-type="journal"><name><surname>Kaufman</surname><given-names>CE</given-names></name>, <name><surname>Stavrou</surname><given-names>SE</given-names></name>. <article-title>“Bus fare please”: the economics of sex and gifts among young people in urban South Africa</article-title>. <source>Cult Health Sex</source>. <year>2004</year>;<volume>6</volume>: <fpage>377</fpage>–<lpage>391</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref025"><label>25</label><mixed-citation publication-type="journal"><name><surname>Leclerc-Madlala</surname><given-names>S</given-names></name>. <article-title>Age-disparate and intergenerational sex in southern Africa: the dynamics of hypervulnerability</article-title>. <source>AIDS</source>. <year>2008</year>;<volume>22</volume><issue>Suppl 4</issue>:<fpage>S17</fpage>–<lpage>S25</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/01.aids.0000341774.86500.53">10.1097/01.aids.0000341774.86500.53</ext-link></comment><pub-id pub-id-type="pmid">19033752</pub-id></mixed-citation></ref><ref id="pone.0159162.ref026"><label>26</label><mixed-citation publication-type="journal"><name><surname>Miller</surname><given-names>KS</given-names></name>, <name><surname>Clark</surname><given-names>LF</given-names></name>, <name><surname>Moore</surname><given-names>JS</given-names></name>. <article-title>Sexual initiation with older male partners and subsequent HIV risk behavior among female adolescents</article-title>. <source>Fam Plann Perspect</source>. <year>1997</year>;<volume>29</volume>: <fpage>212</fpage>–<lpage>214</lpage>. <pub-id pub-id-type="pmid">9323497</pub-id></mixed-citation></ref><ref id="pone.0159162.ref027"><label>27</label><mixed-citation publication-type="journal"><name><surname>Wood</surname><given-names>K</given-names></name>, <name><surname>Maforah</surname><given-names>F</given-names></name>, <name><surname>Jewkes</surname><given-names>R</given-names></name>. <article-title>“He forced me to love him”: putting violence on adolescent sexual health agendas</article-title>. <source>Soc Sci Med</source>. <year>1998</year>;<volume>47</volume>: <fpage>233</fpage>–<lpage>242</lpage>. <pub-id pub-id-type="pmid">9720642</pub-id></mixed-citation></ref><ref id="pone.0159162.ref028"><label>28</label><mixed-citation publication-type="journal"><name><surname>Britton</surname><given-names>A</given-names></name>, <name><surname>Ben-Shlomo</surname><given-names>Y</given-names></name>, <name><surname>Benzeval</surname><given-names>M</given-names></name>, <name><surname>Kuh</surname><given-names>D</given-names></name>, <name><surname>Bell</surname><given-names>S</given-names></name>. <article-title>Life course trajectories of alcohol consumption in the United Kingdom using longitudinal data from nine cohort studies</article-title>. <source>BMC Med</source>. <year>2015</year>;<volume>13</volume>: <fpage>47</fpage><comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1186/s12916-015-0273-z">10.1186/s12916-015-0273-z</ext-link></comment><pub-id pub-id-type="pmid">25858476</pub-id></mixed-citation></ref><ref id="pone.0159162.ref029"><label>29</label><mixed-citation publication-type="journal"><name><surname>Maughan-Brown</surname><given-names>B</given-names></name>, <name><surname>Kenyon</surname><given-names>C</given-names></name>, <name><surname>Lurie</surname><given-names>MN</given-names></name>. <article-title>Partner Age Differences and Concurrency in South Africa: Implications for HIV-Infection Risk Among Young Women</article-title>. <source>AIDS Behav</source>. <year>2014</year>;<volume>18</volume>: <fpage>2469</fpage>–<lpage>2476</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1007/s10461-014-0828-6">10.1007/s10461-014-0828-6</ext-link></comment><pub-id pub-id-type="pmid">25047687</pub-id></mixed-citation></ref><ref id="pone.0159162.ref030"><label>30</label><mixed-citation publication-type="journal"><name><surname>Lurie</surname><given-names>M</given-names></name>, <name><surname>Pronyk</surname><given-names>P</given-names></name>, <name><surname>de Moor</surname><given-names>E</given-names></name>, <name><surname>Heyer</surname><given-names>A</given-names></name>, <name><surname>de Bruyn</surname><given-names>G</given-names></name>, <name><surname>Struthers</surname><given-names>H</given-names></name>, <etal>et al</etal><article-title>Sexual behavior and reproductive health among HIV-infected patients in urban and rural South Africa</article-title>. <source>J Acquir Immune Defic Syndr</source>. <year>2008</year>;<volume>47</volume>:<fpage>484</fpage>–<lpage>93</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAI.0b013e3181648de8">10.1097/QAI.0b013e3181648de8</ext-link></comment><pub-id pub-id-type="pmid">18209685</pub-id></mixed-citation></ref><ref id="pone.0159162.ref031"><label>31</label><mixed-citation publication-type="journal"><name><surname>Darj</surname><given-names>E</given-names></name>, <name><surname>Mirembe</surname><given-names>FM</given-names></name>, <name><surname>Råssjö</surname><given-names>E-B</given-names></name>. <article-title>STI-prevalence and differences in social background and sexual behavior among urban and rural young women in Uganda</article-title>. <source>Sex Reprod Healthc</source>. <year>2010</year>;<volume>1</volume>:<fpage>111</fpage>–<lpage>5</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.srhc.2010.03.001">10.1016/j.srhc.2010.03.001</ext-link></comment><pub-id pub-id-type="pmid">21122607</pub-id></mixed-citation></ref><ref id="pone.0159162.ref032"><label>32</label><mixed-citation publication-type="journal"><name><surname>Dodoo</surname><given-names>FN-A</given-names></name>, <name><surname>Zulu</surname><given-names>EM</given-names></name>, <name><surname>Ezeh</surname><given-names>AC</given-names></name>. <article-title>Urban–rural differences in the socioeconomic deprivation–Sexual behavior link in Kenya</article-title>. <source>Soc Sci Med</source>. <year>2007</year>;<volume>64</volume>:<fpage>1019</fpage>–<lpage>31</lpage>. <pub-id pub-id-type="pmid">17113695</pub-id></mixed-citation></ref><ref id="pone.0159162.ref033"><label>33</label><mixed-citation publication-type="journal"><name><surname>Tumwesigye</surname><given-names>NM</given-names></name>, <name><surname>Ingham</surname><given-names>R</given-names></name>, <name><surname>Holmes</surname><given-names>D</given-names></name>. <article-title>Condom use at first and latest sexual events among young people: evidence from a rural and peri-urban setting in Uganda</article-title>. <source>Afr. Health Sci</source>. <year>2013</year>;<volume>13</volume>:<fpage>1</fpage>–<lpage>8</lpage>.<pub-id pub-id-type="pmid">23658561</pub-id></mixed-citation></ref><ref id="pone.0159162.ref034"><label>34</label><mixed-citation publication-type="journal"><name><surname>Voeten</surname><given-names>H</given-names></name>, <name><surname>Egesah</surname><given-names>O</given-names></name>, <name><surname>Habbema</surname><given-names>J</given-names></name>. <article-title>Sexual Behavior Is More Risky in Rural Than in Urban Areas Among Young Women in Nyanza Province, Kenya</article-title>. <source>Sex Transm Dis</source>. <year>2004</year>;<volume>31</volume>:<fpage>481</fpage>–<lpage>7</lpage>. <pub-id pub-id-type="pmid">15273581</pub-id></mixed-citation></ref><ref id="pone.0159162.ref035"><label>35</label><mixed-citation publication-type="journal"><name><surname>Voeten</surname><given-names>H</given-names></name>, <name><surname>Egesah</surname><given-names>O</given-names></name>, <name><surname>Varkevisser</surname><given-names>C</given-names></name>, <name><surname>Habbema</surname><given-names>J</given-names></name>. <article-title>Female sex workers and unsafe sex in urban and rural Nyanza, Kenya: regular partners may contribute more to HIV transmission than clients</article-title>. <source>Trop Med Int Health</source>. <year>2006</year>;<volume>12</volume>:<fpage>174</fpage>–<lpage>182</lpage>.<pub-id pub-id-type="pmid">17300623</pub-id></mixed-citation></ref><ref id="pone.0159162.ref036"><label>36</label><mixed-citation publication-type="journal"><name><surname>Papo</surname><given-names>JK</given-names></name>, <name><surname>Bauni</surname><given-names>EK</given-names></name>, <name><surname>Sanders</surname><given-names>EJ</given-names></name>, <name><surname>Brocklehurst</surname><given-names>P</given-names></name>, <name><surname>Jaffe</surname><given-names>HW</given-names></name>. <article-title>Exploring the condom gap: is supply or demand the limiting factor–condom access and use in an urban and a rural setting in Kilifi district, Kenya</article-title>. <source>AIDS</source>. <year>2011</year>;<volume>25</volume>:<fpage>247</fpage>–<lpage>55</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAD.0b013e328341b9b8">10.1097/QAD.0b013e328341b9b8</ext-link></comment><pub-id pub-id-type="pmid">21150559</pub-id></mixed-citation></ref><ref id="pone.0159162.ref037"><label>37</label><mixed-citation publication-type="book"><name><surname>Johnson</surname><given-names>S</given-names></name>, <name><surname>Kincaid</surname><given-names>DL</given-names></name>, <name><surname>Figueroa</surname><given-names>M</given-names></name>, <name><surname>Delate</surname><given-names>R</given-names></name>, <name><surname>Mahlasela</surname><given-names>L</given-names></name>, <name><surname>Magni</surname><given-names>S</given-names></name>. <source>The Third National HIV Communication Survey, 2012</source>. <publisher-loc>Pretoria</publisher-loc>: <publisher-name>JHHESA</publisher-name>; <year>2013</year> Available: <ext-link ext-link-type="uri" xlink:href="http://jhhesa.org/sites/default/files/hiv_survey.pdf">http://jhhesa.org/sites/default/files/hiv_survey.pdf</ext-link></mixed-citation></ref><ref id="pone.0159162.ref038"><label>38</label><mixed-citation publication-type="book"><name><surname>Shisana</surname><given-names>O</given-names></name>, <name><surname>Rehle</surname><given-names>T</given-names></name>, <name><surname>Simbayi</surname><given-names>L</given-names></name>, <name><surname>Zuma</surname><given-names>K</given-names></name>, <name><surname>Jooste</surname><given-names>S</given-names></name>, <name><surname>Zunga</surname><given-names>N</given-names></name>, <etal>et al</etal><source>South African National HIV Prevalence, Incidence and Behaviour Survey, 2012</source>. <publisher-loc>Cape Town</publisher-loc>: <publisher-name>Human Sciences Research Council Press</publisher-name>; <year>2014</year> Available: <ext-link ext-link-type="uri" xlink:href="http://www.hsrc.ac.za/en/research-data/view/6871">http://www.hsrc.ac.za/en/research-data/view/6871</ext-link></mixed-citation></ref><ref id="pone.0159162.ref039"><label>39</label><mixed-citation publication-type="journal"><name><surname>Kenyon</surname><given-names>C</given-names></name>, <name><surname>Colebunders</surname><given-names>R</given-names></name>. <article-title>Birds of a feather: homophily and sexual network structure in sub-Saharan Africa</article-title>. <source>Int J STD AIDS</source>. <year>2013</year>;<volume>24</volume>: <fpage>211</fpage>–<lpage>215</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1177/0956462412472455">10.1177/0956462412472455</ext-link></comment><pub-id pub-id-type="pmid">23535354</pub-id></mixed-citation></ref><ref id="pone.0159162.ref040"><label>40</label><mixed-citation publication-type="journal"><name><surname>Morris</surname><given-names>M</given-names></name>. <article-title>Barking up the Wrong Evidence Tree. Comment on Lurie & Rosenthal, “Concurrent Partnerships as a Driver of the HIV Epidemic in Sub-Saharan Africa? The Evidence is Limited.”</article-title><source>AIDS Behav</source>. <year>2010</year>;<volume>14</volume>: <fpage>31</fpage>–<lpage>33</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1007/s10461-009-9639-6">10.1007/s10461-009-9639-6</ext-link></comment><pub-id pub-id-type="pmid">19997971</pub-id></mixed-citation></ref><ref id="pone.0159162.ref041"><label>41</label><mixed-citation publication-type="journal"><name><surname>Cameron</surname><given-names>AC</given-names></name>, <name><surname>Miller</surname><given-names>DL</given-names></name>. <article-title>A Practitioner’s Guide to Cluster-Robust Inference</article-title>. <source>J Hum Resour</source>. <year>2015</year>;<volume>50</volume>:<fpage>317</fpage>–<lpage>72</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref042"><label>42</label><mixed-citation publication-type="journal"><name><surname>Knaub</surname><given-names>JR</given-names></name>. <article-title>Practical interpretation of hypothesis tests—letter to the editor</article-title>. <source>The American Statistician</source>. <year>1987</year>;<volume>41</volume>:<fpage>246</fpage>–<lpage>7</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref043"><label>43</label><mixed-citation publication-type="journal"><name><surname>Schroder</surname><given-names>KEE</given-names></name>, <name><surname>Carey</surname><given-names>MP</given-names></name>, <name><surname>Vanable</surname><given-names>PA</given-names></name>. <article-title>Methodological challenges in research on sexual risk behavior: II. Accuracy of self-reports</article-title>. <source>Ann Behav Med</source>. <year>2003</year>;<volume>26</volume>: <fpage>104</fpage>–<lpage>123</lpage>. <pub-id pub-id-type="pmid">14534028</pub-id></mixed-citation></ref><ref id="pone.0159162.ref044"><label>44</label><mixed-citation publication-type="journal"><name><surname>Longfield</surname><given-names>K</given-names></name>, <name><surname>Glick</surname><given-names>A</given-names></name>, <name><surname>Waithaka</surname><given-names>M</given-names></name>, <name><surname>Berman</surname><given-names>J</given-names></name>. <article-title>Relationships between older men and younger women: implications for STIs/HIV in Kenya</article-title>. <source>Stud Family Plann</source>. <year>2004</year>;<volume>35</volume>: <fpage>125</fpage>–<lpage>134</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref045"><label>45</label><mixed-citation publication-type="journal"><name><surname>Silberschmidt</surname><given-names>M</given-names></name>, <name><surname>Rasch</surname><given-names>V</given-names></name>. <article-title>Adolescent girls, illegal abortions and “sugar-daddies” in Dar es Salaam: vulnerable victims and active social agents</article-title>. <source>Soc Sci Med</source>. <year>2001</year>;<volume>52</volume>: <fpage>1815</fpage>–<lpage>1826</lpage>. <pub-id pub-id-type="pmid">11352408</pub-id></mixed-citation></ref><ref id="pone.0159162.ref046"><label>46</label><mixed-citation publication-type="journal"><name><surname>Ott</surname><given-names>MQ</given-names></name>, <name><surname>Bärnighausen</surname><given-names>T</given-names></name>, <name><surname>Tanser</surname><given-names>F</given-names></name>, <name><surname>Lurie</surname><given-names>MN</given-names></name>, <name><surname>Newell</surname><given-names>M-L</given-names></name>. <article-title>Age-gaps in sexual partnerships: seeing beyond “sugar daddies.”</article-title><source>AIDS</source>. <year>2011</year>;<volume>25</volume>:<fpage>861</fpage>–<lpage>3</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAD.0b013e32834344c9">10.1097/QAD.0b013e32834344c9</ext-link></comment><pub-id pub-id-type="pmid">21358377</pub-id></mixed-citation></ref><ref id="pone.0159162.ref047"><label>47</label><mixed-citation publication-type="journal"><name><surname>Karlyn</surname><given-names>AS</given-names></name>. <article-title>Intimacy revealed: sexual experimentation and the construction of risk among young people in Mozambique</article-title>. <source>Cult Health Sex</source>. <year>2005</year>;<volume>7</volume>:<fpage>279</fpage>–<lpage>92</lpage>. <pub-id pub-id-type="pmid">16864203</pub-id></mixed-citation></ref><ref id="pone.0159162.ref048"><label>48</label><mixed-citation publication-type="journal"><name><surname>Masvawure</surname><given-names>T</given-names></name>. <article-title>“I just need to be flashy on campus”: female students and transactional sex at a university in Zimbabwe</article-title>. <source>Cult Health Sex</source>. <year>2010</year>;<volume>12</volume>:<fpage>857</fpage>–<lpage>70</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1080/13691050903471441">10.1080/13691050903471441</ext-link></comment><pub-id pub-id-type="pmid">20069476</pub-id></mixed-citation></ref><ref id="pone.0159162.ref049"><label>49</label><mixed-citation publication-type="journal"><name><surname>Mavhandu-Mudzusi</surname><given-names>AH</given-names></name>, <name><surname>Sandy</surname><given-names>PT</given-names></name>, <name><surname>Francis</surname><given-names>TK</given-names></name>. <article-title>Factors Contributing to Intergenerational Sexual Relationships among Refugee Girls in the City of Tshwane, South Africa</article-title>. <source>MJSS</source>. <year>2014</year>;<volume>5</volume>:<fpage>2876</fpage>–<lpage>85</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref050"><label>50</label><mixed-citation publication-type="journal"><name><surname>Nyanzi</surname><given-names>S</given-names></name>, <name><surname>Pool</surname><given-names>R</given-names></name>, <name><surname>Kinsman</surname><given-names>J</given-names></name>. <article-title>The negotiation of sexual relationships among school pupils in south-western Uganda</article-title>. <source>AIDS Care</source>. <year>2001</year>;<volume>13</volume>:<fpage>83</fpage>–<lpage>98</lpage>. <pub-id pub-id-type="pmid">11177467</pub-id></mixed-citation></ref><ref id="pone.0159162.ref051"><label>51</label><mixed-citation publication-type="journal"><name><surname>Hunter</surname><given-names>M</given-names></name>. <article-title>The Materiality of Everyday Sex: thinking beyond “prostitution.”</article-title><source>African Studies</source>. <year>2002</year>;<volume>61</volume>:<fpage>99</fpage>–<lpage>120</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref052"><label>52</label><mixed-citation publication-type="journal"><name><surname>Stephenson</surname><given-names>R</given-names></name>, <name><surname>Winter</surname><given-names>A</given-names></name>, <name><surname>Elfstrom</surname><given-names>M</given-names></name>. <article-title>Community environments shaping transactional sex among sexually active men in Malawi, Nigeria, and Tanzania</article-title>. <source>AIDS Care</source>. <year>2013</year>;<volume>25</volume>:<fpage>784</fpage>–<lpage>92</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1080/09540121.2012.748161">10.1080/09540121.2012.748161</ext-link></comment><pub-id pub-id-type="pmid">23215551</pub-id></mixed-citation></ref><ref id="pone.0159162.ref053"><label>53</label><mixed-citation publication-type="journal"><name><surname>Choudhry</surname><given-names>V</given-names></name>, <name><surname>Ambresin</surname><given-names>A-E</given-names></name>, <name><surname>Nyakato</surname><given-names>VN</given-names></name>, <name><surname>Agardh</surname><given-names>A</given-names></name>. <article-title>Transactional sex and HIV risks—evidence from a cross-sectional national survey among young people in Uganda</article-title>. <source>Global Health Act</source>. <year>2014</year>;<volume>8</volume>:<fpage>27249</fpage>.</mixed-citation></ref><ref id="pone.0159162.ref054"><label>54</label><mixed-citation publication-type="journal"><name><surname>Mantell</surname><given-names>JE</given-names></name>, <name><surname>LeVasseur</surname><given-names>MT</given-names></name>, <name><surname>Sun</surname><given-names>X</given-names></name>, <name><surname>Zhou</surname><given-names>J</given-names></name>, <name><surname>Mao</surname><given-names>J</given-names></name>, <name><surname>Peng</surname><given-names>Y</given-names></name>, <etal>et al</etal><article-title>What role does transactional sex play in the HIV/STI and reproductive health risk behaviour among high-tier entertainment centre workers in China?</article-title><source>Global Public Health</source>. <year>2015</year>;<volume>10</volume>: <fpage>947</fpage>–<lpage>967</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1080/17441692.2015.1045918">10.1080/17441692.2015.1045918</ext-link></comment><pub-id pub-id-type="pmid">26274897</pub-id></mixed-citation></ref><ref id="pone.0159162.ref055"><label>55</label><mixed-citation publication-type="journal"><name><surname>Robinson</surname><given-names>J</given-names></name>, <name><surname>Yeh</surname><given-names>E</given-names></name>. <article-title>Transactional sex as a response to risk in Western Kenya</article-title>. <source>American Economic Journal: Applied Economics</source>. <year>2011</year>;<volume>3</volume>: <fpage>35</fpage>–<lpage>64</lpage>.</mixed-citation></ref><ref id="pone.0159162.ref056"><label>56</label><mixed-citation publication-type="journal"><name><surname>Dunkle</surname><given-names>K</given-names></name>, <name><surname>Jewkes</surname><given-names>R</given-names></name>, <name><surname>Brown</surname><given-names>H</given-names></name>, <name><surname>Gray</surname><given-names>G</given-names></name>. <article-title>Transactional sex among women in Soweto, South Africa: prevalence, risk factors and association with HIV infection</article-title>. <source>Soc Sci Med</source>. <year>2004</year>;<volume>59</volume>: <fpage>1581</fpage>–<lpage>1592</lpage>. <pub-id pub-id-type="pmid">15279917</pub-id></mixed-citation></ref><ref id="pone.0159162.ref057"><label>57</label><mixed-citation publication-type="journal"><name><surname>Jewkes</surname><given-names>R</given-names></name>, <name><surname>Morrell</surname><given-names>R</given-names></name>. <article-title>Gender and sexuality: emerging perspectives from the heterosexual epidemic in South Africa and implications for HIV risk and prevention</article-title>. <source>J Int AIDS Soc</source>. <year>2010</year>;<volume>13</volume>: <fpage>6</fpage><comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1186/1758-2652-13-6">10.1186/1758-2652-13-6</ext-link></comment><pub-id pub-id-type="pmid">20181124</pub-id></mixed-citation></ref><ref id="pone.0159162.ref058"><label>58</label><mixed-citation publication-type="journal"><name><surname>Jewkes</surname><given-names>R</given-names></name>, <name><surname>Morrell</surname><given-names>R</given-names></name>, <name><surname>Sikweyiya</surname><given-names>Y</given-names></name>, <name><surname>Dunkle</surname><given-names>K</given-names></name>, <name><surname>Penn-Kekana</surname><given-names>L</given-names></name>. <article-title>Men, Prostitution and the Provider Role: Understanding the Intersections of Economic Exchange, Sex, Crime and Violence in South Africa</article-title>. <source>PLOS ONE</source>. <year>2012</year>;<volume>7</volume>: <fpage>e40821</fpage><comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1371/journal.pone.0040821">10.1371/journal.pone.0040821</ext-link></comment><pub-id pub-id-type="pmid">22911711</pub-id></mixed-citation></ref><ref id="pone.0159162.ref059"><label>59</label><mixed-citation publication-type="journal"><name><surname>Jewkes</surname><given-names>R</given-names></name>, <name><surname>Morrell</surname><given-names>R</given-names></name>, <name><surname>Sikweyiya</surname><given-names>Y</given-names></name>, <name><surname>Dunkle</surname><given-names>K</given-names></name>, <name><surname>Penn-Kekana</surname><given-names>L</given-names></name>. <article-title>Transactional relationships and sex with a woman in prostitution: prevalence and patterns in a representative sample of South African men</article-title>. <source>BMC Public Health</source>. <year>2012</year>;<volume>12</volume>: <fpage>325</fpage><comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1186/1471-2458-12-325">10.1186/1471-2458-12-325</ext-link></comment><pub-id pub-id-type="pmid">22551102</pub-id></mixed-citation></ref><ref id="pone.0159162.ref060"><label>60</label><mixed-citation publication-type="journal"><name><surname>Pettifor</surname><given-names>AE</given-names></name>, <name><surname>Kleinschmidt</surname><given-names>I</given-names></name>, <name><surname>Levin</surname><given-names>J</given-names></name>, <name><surname>Rees</surname><given-names>HV</given-names></name>, <name><surname>MacPhail</surname><given-names>C</given-names></name>, <name><surname>Madikizela-Hlongwa</surname><given-names>L</given-names></name>, <etal>et al</etal><article-title>A community-based study to examine the effect of a youth HIV prevention intervention on young people aged 15–24 in South Africa: results of the baseline survey</article-title>. <source>Trop Med Int Health</source>. <year>2005</year>;<volume>10</volume>: <fpage>971</fpage>–<lpage>980</lpage>. <pub-id pub-id-type="pmid">16185231</pub-id></mixed-citation></ref><ref id="pone.0159162.ref061"><label>61</label><mixed-citation publication-type="journal"><name><surname>Bauman</surname><given-names>LJ</given-names></name>, <name><surname>Berman</surname><given-names>R</given-names></name>. <article-title>Adolescent relationships and condom use: trust, love and commitment</article-title>. <source>AIDS Behav</source>. <year>2005</year>;<volume>9</volume>: <fpage>211</fpage>–<lpage>222</lpage>. <pub-id pub-id-type="pmid">15933840</pub-id></mixed-citation></ref><ref id="pone.0159162.ref062"><label>62</label><mixed-citation publication-type="journal"><name><surname>MacPhail</surname><given-names>C</given-names></name>, <name><surname>Campbell</surname><given-names>C</given-names></name>. <article-title>“I think condoms are good but, aai, I hate those things”:condom use among adolescents and young people in a Southern African township</article-title>. <source>Soc Sci Med</source>. <year>2001</year>;<volume>52</volume>: <fpage>1613</fpage>–<lpage>1627</lpage>. <pub-id pub-id-type="pmid">11327136</pub-id></mixed-citation></ref><ref id="pone.0159162.ref063"><label>63</label><mixed-citation publication-type="journal"><name><surname>Fisher</surname><given-names>J</given-names></name>, <name><surname>Cook</surname><given-names>P</given-names></name>, <name><surname>Sam</surname><given-names>N</given-names></name>. <article-title>Patterns of alcohol use, problem drinking, and HIV infection among high-risk African women</article-title>. <source>Sex Transm Dis</source>. <year>2008</year>;<volume>35</volume>: <fpage>537</fpage>–<lpage>544</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/OLQ.0b013e3181677547">10.1097/OLQ.0b013e3181677547</ext-link></comment><pub-id pub-id-type="pmid">18418292</pub-id></mixed-citation></ref><ref id="pone.0159162.ref064"><label>64</label><mixed-citation publication-type="journal"><name><surname>Kalichman</surname><given-names>SC</given-names></name>, <name><surname>Simbayi</surname><given-names>LC</given-names></name>, <name><surname>Kaufman</surname><given-names>M</given-names></name>, <name><surname>Cain</surname><given-names>D</given-names></name>, <name><surname>Jooste</surname><given-names>S</given-names></name>. <article-title>Alcohol Use and Sexual Risks for HIV/AIDS in Sub-Saharan Africa: Systematic Review of Empirical Findings</article-title>. <source>Prev Sci</source>. <year>2007</year>;<volume>8</volume>: <fpage>141</fpage>–<lpage>151</lpage>. <pub-id pub-id-type="pmid">17265194</pub-id></mixed-citation></ref><ref id="pone.0159162.ref065"><label>65</label><mixed-citation publication-type="book"><name><surname>Shisana</surname><given-names>O</given-names></name>, <name><surname>Rehle</surname><given-names>T</given-names></name>, <name><surname>Simbayi</surname><given-names>L</given-names></name>, <name><surname>Zuma</surname><given-names>K</given-names></name>, <name><surname>Jooste</surname><given-names>S</given-names></name>, <name><surname>Pillay-van-Wyk</surname><given-names>V</given-names></name>, <etal>et al</etal><source>South African National Prevalence, Incidence, Behaviour and Communication Survey, 2008: a Turning Tide Among Teenagers?</source><publisher-loc>Cape Town</publisher-loc>: <publisher-name>Human Sciences Research Council Press</publisher-name>; <year>2009</year> Available: <ext-link ext-link-type="uri" xlink:href="http://www.health-e.org.za/wp-content/uploads/2013/05/2966e129fc39e07486250fd47fcc266e.pdf">http://www.health-e.org.za/wp-content/uploads/2013/05/2966e129fc39e07486250fd47fcc266e.pdf</ext-link></mixed-citation></ref><ref id="pone.0159162.ref066"><label>66</label><mixed-citation publication-type="journal"><name><surname>Lamb</surname><given-names>MR</given-names></name>, <name><surname>Fayorsey</surname><given-names>R</given-names></name>, <name><surname>Nuwagaba-Biribonwoha</surname><given-names>H</given-names></name>, <name><surname>Viola</surname><given-names>V</given-names></name>, <name><surname>Mutabazi</surname><given-names>V</given-names></name>, <name><surname>Alwar</surname><given-names>T</given-names></name>, <etal>et al</etal><article-title>High attrition before and after ART initiation among youth (15–24 years of age) enrolled in HIV care</article-title>. <source>AIDS</source>. <year>2014</year>;<volume>28</volume>: <fpage>559</fpage>–<lpage>568</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAD.0000000000000054">10.1097/QAD.0000000000000054</ext-link></comment><pub-id pub-id-type="pmid">24076661</pub-id></mixed-citation></ref><ref id="pone.0159162.ref067"><label>67</label><mixed-citation publication-type="journal"><name><surname>Maughan-Brown</surname><given-names>B</given-names></name>, <name><surname>Venkataramani</surname><given-names>A</given-names></name>. <article-title>Measuring concurrent partnerships: potential for underestimation in UNAIDS recommended method</article-title>. <source>AIDS</source>. <year>2011</year>;<volume>25</volume>: <fpage>1549</fpage>–<lpage>1551</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1097/QAD.0b013e32834905c4">10.1097/QAD.0b013e32834905c4</ext-link></comment><pub-id pub-id-type="pmid">21617519</pub-id></mixed-citation></ref><ref id="pone.0159162.ref068"><label>68</label><mixed-citation publication-type="journal"><name><surname>Harling</surname><given-names>G</given-names></name>, <name><surname>Tanser</surname><given-names>F</given-names></name>, <name><surname>Mutevedzi</surname><given-names>T</given-names></name>, <name><surname>Barnighausen</surname><given-names>T</given-names></name>. <article-title>Assessing the validity of respondents’ reports of their partners’ ages in a rural South African population-based cohort</article-title>. <source>BMJ Open</source>. <year>2015</year>; <volume>4</volume>.</mixed-citation></ref><ref id="pone.0159162.ref069"><label>69</label><mixed-citation publication-type="journal"><name><surname>Dunkle</surname><given-names>KL</given-names></name>, <name><surname>Wingood</surname><given-names>GM</given-names></name>, <name><surname>Camp</surname><given-names>CM</given-names></name>, <name><surname>DiClemente</surname><given-names>RJ</given-names></name>. <article-title>Economically motivated relationships and transactional sex among unmarried African American and white women: results from a U.S. national telephone survey</article-title>. <source>Public Health Rep</source>. <year>2010</year>;<volume>125</volume><issue>Suppl 4</issue>: <fpage>90</fpage>–<lpage>100</lpage>. <pub-id pub-id-type="pmid">20626196</pub-id></mixed-citation></ref><ref id="pone.0159162.ref070"><label>70</label><mixed-citation publication-type="journal"><name><surname>Jewkes</surname><given-names>R</given-names></name>, <name><surname>Dunkle</surname><given-names>K</given-names></name>. <article-title>Transactional Sex and HIV Incidence in a Cohort of Young Women in the Stepping Stones Trial</article-title>. <source>J AIDS Clinic Res</source>. <year>2012</year>;<volume>3</volume>:<fpage>158</fpage>.</mixed-citation></ref></ref-list></back></pmc>
