Prevalence of Parkinson's disease in the elderly: a population study in Gironde, France

We investigated the prevalence of Parkinson's disease in a representative sample of the elderly population living in the Gironde département, France. Among 3149 people over age 65, the prevalence ratio for Parkinson's disease was 1.4%, without significant difference between men and women. We found that age-specific prevalence ratios increased with age from 0.5% in the age group 65 to 69 to 6.1% in individuals over age 90. This age pattern is consistent with that found in other population-based studies. Interestingly, the slope of age-specific prevalence ratios for Parkinson's disease was similar to that previously reported for Lewy bodies. Our study showed that a high proportion (42%) of Parkinson's disease cases in elderly subjects living in institutions were undiagnosed.