Parkinson disease associated with farming and exposure to
agricultural chemicals has been reported in numerous studies; little is known about
Parkinson disease risk factors for those living in urban areas. The authors investigated the relation between
copper, lead, or
manganese emissions and
Parkinson disease incidence in the urban United States, studying 29 million Medicare beneficiaries in the year 2003.
Parkinson disease incidence was determined by using beneficiaries who had not changed residence since 1995. Over 35,000 nonmobile incident
Parkinson disease cases, diagnosed by a neurologist, were identified for analysis. Age-, race-, and sex-standardized
Parkinson disease incidence was compared between counties with high cumulative industrial release of
copper,
manganese, or lead (as reported to the Environmental Protection Agency) and counties with no/low reported release of all 3 metals.
Parkinson disease incidence (per 100,000) in counties with no/low
copper/lead/
manganese release was 274.0 (95% confidence interval (CI): 226.8, 353.5). Incidence was greater in counties with high
manganese release: 489.4 (95% CI: 368.3, 689.5) (relative risk = 1.78, 95% CI: 1.54, 2.07) and counties with high
copper release: 304.2 (95% CI: 276.0, 336.8) (relative risk = 1.1, 95% CI: 0.94, 1.31). Urban
Parkinson disease incidence is greater in counties with high reported industrial release of
copper or
manganese. Environmental exposure to metals may be a risk factor for
Parkinson disease in urban areas.