Parkinson's disease and parkinsonism in a longitudinal study - Two-fold higher incidence in men

Objective: To determine the incidence of parkinsonism and PD in the Italian elderly, and to explore the relation with age and gender. Methods: In eigh t Italian municipalities, a population-based, parkinsonism-free cohort was followed for an average of 3 years. At the end of the follow-up, the cohort survivors were directly contacted (screening and clinical examination). Co hort members who had died were studied using death certificates, clinical r ecords, and information gathered from relatives and general practitioners. Parkinsonism diagnosis and subtyping were made according to specified diagn ostic criteria. Results: The cohort consisted of 4,341 individuals (65 to 8 4 years of age): 596 died before the examination, 2,863 (76.4% of the survi vors) completed the screening procedure, and 882 refused to participate. Th e authors found 68 incident cases of parkinsonism: 42 PD (62%), 7 drug-indu ced parkinsonism (10%), 8 parkinsonism in dementia (12%), 8 vascular parkin sonism (12%), and 3 parkinsonism, unspecified (5.8%). Average annual incide nce rate (per 100,000 person-years) in the population aged 65 to 84 years, adjusted to the 1992 Italian population, was 529.7 (95% CI, 400.5 to 658.9) for parkinsonism, and 326.3 (95% CI, 224.1 to 427.5) for PD. Incidence rat es for both parkinsonism and PD increased with age in both men and women; m en had higher rates in every age group. Age-adjusted relative risk in men c ompared with women was 1.66 (95% CI, 1.02 to 2.70) for parkinsonism and 2.1 3 (95% CI, 1.11 to 4.11) for PD. Conclusions: Incidence of parkinsonism and PD increased with age, PD was the most common type of parkinsonism, and me n had a risk of developing PD twice that of women.