Ethnic Differences in Essential Tremor

• DOI: 10.1001/archneur.57.5.723
• Publication Date: 2003-03-18T19:38:01Z
• Authors: Elan D. Louis; Livia F. Barnes; Blair Ford; Seth L. Pullman; Qiping Yu
• Keywords: Aged, 80 and over; Male; Essential Tremor; Hispanic or Latino; Severity of Illness Index; White People; 3. Good health; Black or African American; 03 medical and health sciences; 0302 clinical medicine; Humans; Regression Analysis; Female; Aged

Ethnic differences in the clinical characteristics (severity and distribution) of essential tumor (ET) have not been studied. The presence of these differences suggests that ET is not a homogeneous disease and that there is variability in disease expression under different circumstances. As part of a community-based study, we evaluated a multiethnic group of cases.To assess whether there are ethnic differences in the clinical characteristics of ET.Elderly residents of Washington Heights-Inwood, New York, were enrolled in a community-based health study (N = 2117). Participants underwent a medical interview and a neurological examination conducted by a neurologist, and subjects with ET were identified. These subjects with ET were then enrolled in a community-based study of ET and underwent a tremor interview, a videotaped tremor examination, and in some cases, a performance-based test of function and quantitative computerized tremor analysis. A total tremor score (range, 0-36, with 0 indicating no tremor and 36 indicating maximum tremor) was assigned to each subject based on 2 neurologists' ratings of the tremor examination.Among 62 subjects with ET (white [n = 16], African American [n = 18], and Hispanic [n = 28]), there were ethnic differences in the total tremor score (F = 3.68, P = .03). In a multiple regression model adjusting for age, white subjects had a mean total tremor score that was 5.3 points lower than that of nonwhite subjects (P = .008). We divided the nonwhite group into African American and Hispanic subgroups. In a regression model adjusting for age and duration, the white group had a mean total tremor score that was 6.1 points lower than that of the Hispanic group (P = .07) and 7.2 points lower than that of the African American group (P = .05). The mean performance-based test score was 1.7 times higher in the African American group and 2.1 times higher in the Hispanic group compared with the white group (P = .38). No subjects in the African American group had head tremor, while 4 subjects in the white group (25%) and 8 subjects in the Hispanic group (29%) did have head tremor (chi2 = 6.17, P = .05).There are ethnic differences in the expression of ET, suggesting that ET is not a homogeneous disorder. These differences may reflect phenotypic variability caused by genotypic differences or differences in exposure to environmental factors that influence tremor.