Occupational exposure to manganese, copper, lead, iron, mercury and zinc and the risk of Parkinson's disease

A population-based case-control study was conducted in the Henry Ford Healt h System (HFHS) in metropolitan Detroit to assess occupational exposures to manganese, copper, lead, iron, mercury and zinc as risk factors for Parkin son's disease (PD). Non-demented men and women 50 years of age who were rec eiving primary medical care at HFHS were recruited, and concurrently enroll ed cases (n = 744) and controls (n = 464) were frequency-matched for sex, r ace and age (+/- 5 years). A risk factor questionnaire, administered by tra ined interviewers, inquired about every job held by each subject for 6 mont hs from age 18 onward, including a detailed assessment of actual job tasks, tools and environment. An experienced industrial hygienist, blinded to sub jects' case-control status, used these data to rate every job as exposed or not exposed to one or more of the metals of interest. Adjusting for sex, r ace, age and smoking status, 20 years of occupational exposure to any metal was not associated with PD. However, more than 20 years exposure to mangan ese (Odds Ratio [OR] = 10.61, 95% Confidence Interval [CI] = 1.06, 105.83) or copper (OR = 2.49, 95% CI = 1.06,5.89) was associated with PD. Occupatio nal exposure for > 20 years to combinations of lead-copper (OR = 5.24, 95% CI = 1.59,17.21), lead-iron (OR = 2.83, 95% CI = 1.07,7.50), and iron-coppe r (OR = 3.69, 95% CI = 7.40, 9.71) was also associated with the disease. No association of occupational exposure to iron, mercury or zinc with PD was found. A lack of statistical power precluded analyses of metal combinations for chose with a low prevalence of exposure (i.e., manganese, mercury and zinc). Our findings suggest that chronic occupational exposure to manganese or copper, individually, or to dual combinations of lead iron and copper, is associated with PD. (C) 1999 Infer Press, Inc.