Previous studies have shown that trichloroethylene (TCE) exposure among factory workers is associated with a higher incidence of Parkinson’s disease (PD). Similarly, an increased risk of PD has been reported among U.S. Marines stationed at Camp Lejeune, North Carolina, where drinking water was contaminated with high concentrations of TCE. Since dry cleaners are a potential source of environmental exposure to TCE, researchers investigated whether residential proximity to dry cleaners was associated with PD incidence.

The study analyzed data from U.S. Medicare beneficiaries aged 67 years and older, including 180,982 individuals with incident PD and 18,848,268 non-case controls. After accounting for age, sex, race, smoking, healthcare utilization, rural-urban commuting area, PM2.5, and income, a dose-dependent association between residential distance from dry cleaners and PD risk was…