Differences in the prevalence of essential tremor among elderly African Americans, whites, and Hispanics in northern Manhattan, NY

E. D. Louis, K. Marder, L. Cote, S. Pullman, B. Ford, D. Wilder, M. X. Tang, R. Lantigua, B. Gurland and R. Mayeux
Department of Neurology, Gertrude H. Sergievsky Center, New York, NY, USA.

BACKGROUND: Until now there has been only one community-based study to examine interethnic differences in the prevalence of essential tremor (ET). The study suggested a higher prevalence among whites than African Americans. The present study is the first to examine differences in the prevalence of ET among Hispanics, African Americans, and whites. OBJECTIVE: To estimate the prevalence of essential tremor (ET) in a cohort of community-dwelling elderly of mixed ethnic background. METHODS: A random sample of 2117 Medicare recipients residing in Washington Heights-Inwood in northern Manhattan, NY, were interviewed. A standardized neurological assessment was performed on those who had neurological complaints and on a random sample of those who did not. Essential tremor was defined as a postural or kinetic tremor of the head or limbs. Diagnoses were independently confirmed by two neurologists based on videotaped examination. RESULTS: After age adjustment to the 1990 Washington Heights-Inwood census, the prevalence of ET was 40.2 per 1000 (95% confidence interval, 31.8 to 48.6). Among 46 cases with ET, ET was significantly more prevalent in men than in women (chi 2 = 5.0, P = .03). Prevalence increased significantly with age. The prevalence was higher in whites than African Americans. The prevalence in Hispanics was intermediate. CONCLUSION: The prevalence of ET increases with age and may be higher among men and whites. Prospective studies are needed to further examine these associations.