High levels of manganese and copper pollution in urban areas are linked to an increased risk of Parkinson’s disease, according to a large-scale analysis of urban pollution and Parkinson’s incidence in the United States.
Scientists at the School of Medicine found that people living in areas with higher levels of manganese pollution had a 78 percent greater risk of developing Parkinson’s disease than those living in pollution-free areas. High levels of copper in the environment increased Parkinson’s risk by 11 percent.
“We’re following up with individual patients, examining exposure histories, disease progression and responses to treatments. If those studies confirm this correlation, we may need to re-evaluate the limits we place on environmental discharges of these pollutants,” says lead author Allison Wright Willis, MD, assistant professor of neurology.
The comparison, published in American Journal of Epidemiology, was conducted using Medicare data and industrial discharge reports to the Environmental Protection Agency (EPA).
“Every year since 1988, any factory or other industry that releases more than a predefined amount of any of 650 chemicals into the environment has to report those discharges to the EPA,” Willis says. “We used that data to construct a comparison of areas with high levels of manganese and copper pollution versus areas where there were few or no releases of those elements.”
Willis and her colleagues then used Medicare data to identify 35,000 Parkinson’s patients. When adjusted for age, race and sex, there were 274 new cases of Parkinson’s disease per 100,000 people in areas with little or no reported manganese or copper pollution. In areas with high manganese pollution, that number rose to 489, and in areas with high copper levels, it increased to 304.
Many different industries — including food, tobacco, furniture, apparel and electrical equipment — produced the pollutant emissions in the geographic areas studied.
“These pollutants are everywhere, and I think that strongly emphasizes the need to look into their effects in greater detail,” Willis says.