To determine if important geographic differences exist in treatment rates for osteoporosis and whether this variation can be explained by regional variation in risk factors.

The Global Longitudinal Study of Osteoporosis in Women is an observational study of women ≥55 years sampled from primary care practices in 10 countries. Self-administered questionnaires were used to collect data on patient characteristics, risk factors for fracture, previous fractures, anti-osteoporosis medication, and health status.

Among 58,009 women, current anti-osteoporosis medication use was lowest in Northern Europe (16%) and highest in USA and Australia (32%). Between 48% (USA, Southern Europe) and 68% (Northern Europe) of women aged ≥65 years with a history of spine or hip fracture since age 45 were untreated. Among women with osteoporosis, the percentage of treated cases was lowest in Europe (45– 52% versus 62–65% elsewhere). Women with osteopenia and no other risk factors were treated with anti-osteoporosis medication most frequently in USA (31%) and Canada (31%), and least frequently in Southern Europe (12%), Northern Europe (13%), and Australia (16%). After adjusting for risk factors, US women were threefold as likely to be treated with anti-osteoporosis medication as Northern European women (odds ratio 2.8; 95% confidence interval 2.5–3.1) and 1.5 times as likely to be treated as Southern European women (1.5, 1.4–1.6). Up to half of women reporting previous hip or spine fracture did not receive treatment.

The likelihood of being treated for osteoporosis differed between regions, and cannot be explained by variation in risk factors. Many women at risk of fracture do not receive prophylaxis.