title: Familial aggregation of Parkinson's disease in a multiethnic community-based case-control study.
abstract: To assess the familial aggregation of Parkinson's disease (PD), we compared the cumulative incidence of PD among first-degree relatives of PD cases and controls. We identified newly diagnosed patients with PD (n = 573) during 1994 to 1995 within Kaiser Permanente Medical Care Program of Northern California and recruited 496 cases (87%) for the case-control study. Of 720 eligible controls matched by birth year and sex to cases, 541 (75%) agreed to participate. Information on family history of PD and other neurodegenerative diseases was obtained by in-person structured interview. We used the reconstructed cohort approach that provides a better estimate of the risk. The cumulative incidence of PD was significantly higher among relatives of PD patients compared with relatives of controls (2.0 vs. 0.7%; relative risk (RR) = 3.4, 95% confidence interval (CI) 1.9-5.9; P = 0.0001). The degree of familial aggregation was higher among first-degree relatives of Hispanic PD cases compared with Hispanic controls (3.7% vs. 0.4%; RR = 8.5, 95% CI 1.0-68.9) than it was among non-Hispanic Caucasian cases and controls (2.0% vs. 0.8%; RR = 2.7, 95% CI 1.5-5.1; P = 0.02). The familial aggregation of PD was stronger among the siblings of PD cases (RR = 5.4, 95% CI 1.8-16.0) than among parents (RR = 2.7, 95% CI 1.3-5.2). The incidence and familial aggregation of PD is highest among Hispanics, warranting further studies of genetic and environmental risk factors in the Hispanic population.
authors.affiliation: Department of Health Research and Policy, Division of Epidemiology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Shino
authors.forename: Valerie
authors.initials: V
authors.lastname: McGuire
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Van Den Eeden
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Tanner
authors.forename: Rita
authors.initials: R
authors.lastname: Popat
authors.forename: Amethyst
authors.initials: A
authors.lastname: Leimpeter
authors.forename: Allan L
authors.initials: AL
authors.lastname: Bernstein
authors.forename: Lorene M
authors.initials: LM
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010300:Parkinson Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors