Mild Parkinsonian signs (MPS, impaired gait, rigidity, bradykinesia, rest tremor) are commonly found during the clinical examination of older people and may be a precursor to Parkinson’s disease (PD) or Alzheimer’s disease (AD). Marked deficits in olfaction occur in PD and AD.

To determine whether University of Pennsylvania Smell Test (UPSIT) scores were lower in non-demented community-dwelling elderly with vs. without MPS.

Non-demented persons age ≥65 years without PD in Washington Heights-Inwood, NY were evaluated with an abbreviated motor Unified Parkinson’s Disease Rating Scale and a 40-item UPSIT. Lower UPSIT and higher transformed UPSIT score (square root [UPSIT — 41]) indicated greater olfactory dysfunction.

One-hundred-seventy-seven (16.4%) of 1,078 participants had MPS. Mean UPSIT scores (MPS vs. without MPS) were 24.3±7.1 vs. 26.4±6.8, p< 0.001. In a logistic regression analysis adjusting for age and education, transformed UPSIT score was associated with MPS (OR 1.25, 95% CI 1.04 – 1.52, p = 0.02). In an adjusted logistic regression analysis, participants with higher transformed UPSIT scores (based on a median split) were 1.55 times more likely to have MPS than were those with lower scores (p = 0.01). Within transformed UPSIT score quartiles, the odds of having MPS were 1.0 (reference), 1.35, 2.02, and 2.20 (p < 0.05). The association with transformed UPSIT scores was similar across MPS sub-types (axial dysfunction, rigidity, tremor).

MPS were associated with a mild reduction in olfactory function. These observations further support the view of MPS as a marker of emerging degenerative brain pathologies.