Frequency of Parkinsonism and Parkinson Disease in African Americans in the Chicago Community.

BACKGROUND

There is paucity of data about African American (AA) patients with Parkinson's disease (PD) and parkinsonism which may precede PD in older adults. Prior studies suggest that there are lower rates of PD in the AA population, with more cognitive impairment in AA with PD. This study aimed to investigate differences in PD, parkinsonism, and cognition between White and AA populations in 3 longitudinal epidemiologic cohort studies of aging.

METHODS

This study examined parkinsonism, PD frequency, and cognition of community-dwelling older individuals in 3 longitudinal epidemiologic cohort studies. Parkinsonism was based on an exam utilizing the modified Unified Parkinson's Disease Rating Scale performed by a nurse. PD was based on self-report, medications used for treatment of PD, and examination findings. Cognition was assessed using 19 performance-based tests that assess 5 cognitive domains.

RESULTS

AA participants were less likely to have parkinsonism compared to Whites, even with age and gender differences. Frequency of PD was not significant between groups. AA were more likely to have lower cognitive scores as compared to Whites. AA were less likely to have parkinsonism even with controlling for cognitive differences between groups.

CONCLUSIONS

Parkinsonian signs are present among AA in the community at lower rates than in White individuals. Cognitive profiles of AA and Whites with parkinsonism may be different, suggesting differing contributions of pathology to cognitive decline and parkinsonism between groups. Additional research is needed to understand the progression of parkinsonism to PD, as well as to understanding the cognitive differences in AA with parkinsonism.