Objective: We sought to evaluate rates of hospitalizations for neurodegenerative disorders in a cohort of Danish metal manufacturing employees.
Methods: A retrospective cohort study was conducted from 1977 to 2002 among 27,839 male Danish metal-manufacturing employees, with 9,817 of those employed in departments engaged in mild or stainless-steel welding and 6,163 welders.
Results: The standardized hospitalization ratio and 95% confidence intervals (CI) for Parkinson's disease were 0.9 (CI = 0.7-1.2) for men in steel-manufacturing companies, 1.0 (CI = 0.7-1.5) for men in welding departments, and 0.9 (CI = 0.4-1.5) for welders. Observed numbers for other neurological conditions were small and not above population expectations. Analyses for time period worked, age, and duration of welding were unremarkable.
Conclusions: This relatively large cohort study with long-term follow-up provides no support for the hypothesis that rates of hospitalization for Parkinson's disease or other neurological conditions are elevated under the exposure circumstances of these Danish workers.