THE FREQUENCY OF IDIOPATHIC PARKINSONS-DISEASE BY AGE, ETHNIC-GROUP, AND SEX IN NORTHERN MANHATTAN, 1988-1993

Sex and ethnic differences in the frequency of Parkinsons's disease ha ve become increasingly important, because putative genetic and environ mental risk factors have been identified. The authors estimated the pr evalence and incidence of Parkinson's disease in a culturally diverse community in New York City over a 4-year period (January 1, 1988-Decem ber 31, 1991) using a disease registry substantiated, for older indivi duals, by a subsequent survey of a random sample of Medicare recipient s between January 1, 1992, and December 31, 1993. The prevalence rate was 107 per 100,000 persons, and over a 3-year period the average inci dence rate was 13 per 100,000 person-years. Age-adjusted prevalence ra tes were lower for women than for men in each ethnic group and were lo wer for blacks than for whites and Hispanics. Incidence rates were hig hest among black men, but they were otherwise comparable across the se x and ethnic groups. The estimated cumulative incidence of Parkinson's disease up to age 90 years was lower for women than for men, which co uld partially explain the lower prevalence rate. By ethnic group, the cumulative incidence was higher for blacks than for whites and Hispani cs, but more deaths occurred among incident black cases. Discrepant pr evalence and incidence rates of Parkinson's disease among blacks and w omen warrant further investigation. While selective mortality could pa rtially account for this paradox, it is also possible that a delay in diagnosis due to limited access to appropriate health services among t hese individuals could have resulted in the observed discordant rates of disease.