Occupational categories at risk for Parkinson's disease.

BACKGROUND: The etiology of Parkinson's disease (PD) is considered to have a strong environmental component, but relatively few studies have investigated the potential association between occupation and the disease. METHODS: In a population-based case-control study, we collected comprehensive occupational histories from all study participants, 144 case and 464 control subjects. RESULTS: Chi-square analysis revealed that working in an agricultural occupation increased estimated PD risk (OR = 1.74; 95% CI = 0.85, 3.60). In contrast, a history of ever working in a service occupation was negatively associated with PD risk (OR = 0.69; 95% CI = 0.47, 1.00). Risk estimates were close to one for specific service occupations. Adjusted odds ratios for all non-service occupational and industrial categories were similar, and working in a service occupation was the only significant inverse predictor of PD risk. CONCLUSIONS: Future investigations focusing on lifestyle factors and environmental exposures within the agricultural and service occupational categories are warranted.

Familial risk ratio of sarcoidosis in African-American sibs and parents.

While sarcoidosis is thought to aggregate in families, little is known about the risk to relatives of sarcoidosis patients. To estimate the familial risk ratio (lambda) of sarcoidosis in sibs and parents of cases, the authors studied 179 African-American families ascertained through an index sarcoidosis case diagnosed at Henry Ford Hospital in Detroit, Michigan. Among those relatives enrolled between 1997 and 1999, 12 of 327 (3.7%) sibs and 11 of 161 (6.8%) parents reported a history of sarcoidosis. The lambda in this sample of relatives, estimated by computing an age, sex, and race standardized incidence ratio, was 2.24 (95% confidence interval: 1.16, 3.92) for sibs and 2.82 (95% confidence interval: 1.41, 5.05) for parents. For sibs and parents combined, lambda was 2.49 (95% confidence interval: 1.58, 3.73). Results stratified by proband characteristics indicated that lambda was greater for relatives of younger (lambda = 2.93, 95% confidence interval: 1.52, 5.12) and male (lambda = 3.98, 95% confidence interval: 1.99, 7.12) probands. A higher lambda was also found for male family members and sibs born later in the birth order. A Monte Carlo method was also used to estimate lambda, with similar results obtained. Overall, these results indicate that, in African Americans, sibs and parents of sarcoidosis cases have about a 2.5-fold increased risk for sarcoidosis and that heterogeneity in disease risk may exist among family members.