Metals have been postulated as environmental concerns in the etiology of Parkinson’s disease (PD), but metal levels are typically measured after diagnosis, which might be subject to reverse causality.
The aim of this study was to investigate the association between prediagnostic blood metal levels and PD risk.
A case-control study was nested in a prospective European cohort, using erythrocyte samples collected before PD diagnosis.
Most assessed metals were not associated with PD risk. Cadmium has a suggestive negative association with PD (odds ratio [95% confidence interval] for the highest quartile, 0.70 [0.42–1.17]), which diminished among never smokers. Among current smokers only, lead was associated with decreased PD risk (0.06 [0.01–0.35]), whereas arsenic showed associations toward an increased PD risk (1.85 [0.45–7.93]).
We observe no strong evidence to support a role of metals in the development of PD. In particular, smoking may confound the association with tobacco-derived metals. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.