Environmental exposure to airborne manganese may increase PD risk
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Key takeaways:
- Researchers analyzed census tract-level estimates for 11 different airborne metals.
- The South and Midwestern regions of the U.S. yielded the highest relative risk of Parkinson’s.
DENVER — Exposure to airborne manganese may be a significant contributing factor to risk of Parkinson’s disease, according to a poster from the American Academy of Neurology annual meeting.
“We wanted to look at residential airborne metals exposure, the environmental exposure people get just from living where they do,” Jordan A. Killion, PhD, MPH, a research scientist in the department of neuroepidemiology at Barrow Neurological Institute, based in Arizona, told Healio.
Previous research has established the neurotoxicity of certain heavy metals, which are likely to present plausible risk factors for PD, Killion and colleagues wrote. They attempted to assess the relationship between environmental exposure to airborne metals and PD risk through a population-based case-control study in the United States.
The Multiple Air Pollutants in PD (MAP-PD) study examined PD risk utilizing Medicare data as well as geocoded nine-digit ZIP codes for participants 2 years prior to diagnosis and selection in 2009. A total of 51,991 incident cases and 13,177,274 controls with complete metals data were included for analysis.
The researchers obtained 2005 census tract-level estimates for air concentrations of 11 airborne metals: antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, mercury, nickel and selenium from all sources as modeled by the EPA.
They employed logistic regression to estimate the relative risk of PD in relation to each metal, adjusting for age, sex, race, smoking and health care utilization. Researchers additionally examined the effect of adjustment for other metals, diesel fuel and fine particulate matter, as well as trichloroethylene.
Results showed a 4.9% greater risk of PD per 0.1 micrograms per cubic meter of exposure to manganese after adjusting for demographics, health care utilization and diesel/fine particulates.
When adjusting for particulate matter, the RR of PD in relation to manganese was 1.007 (95% CI, 1.001-1.012) greater for each standard deviation increase in exposure. Concurrently, ZIP codes with the highest manganese concentrations were similar to those locations with high RRs of disease risk, centered in the South and Midwestern regions of the U.S., Killion and colleagues wrote.
Data also yielded a possible association between PD and beryllium (RR = 1.008; 95% CI, 0.999-1.017), nickel (RR = 1.006; 95% CI, 0.997-1.014) and selenium of similar magnitude. The associations for manganese and nickel were linear with markedly greater RR for PD at the highest manganese exposure levels.
“We found an increased risk of airborne manganese to residential exposure with Parkinson’s disease,” Killion said.