Risk tables for parkinsonism and Parkinson's disease

We applied the incidence rates of parkinsonism and Parkinson's disease (PD) from Olmsted County, MN (1976-1990) to a hypothetical cohort undergoing the mortality rates observed in Minnesota, and computed the lifetime risk and the remaining lifetime risk of developing parkinsonism and PD. These risks were compared to cumulative incidences that do not take competing risks of death into account. The lifetime risk of developing parkinsonism from birth was 4.4% for men and 3.7% for women (ratio = 1.2). The corresponding risk of developing PD was 2.0% for men and 1.3% for women (ratio = 1.5). Because of the opposite effect of higher incidence and higher mortality rates in men, the lifetime risks were only slightly higher in men than in women. Lifetime cumulative incidences were consistently higher than lifetime risks; this difference was more pronounced in men and in older subjects. Lifetime risk estimates are useful in clinical practice, epidemiologic research, and public health.