Researchers at Harvard T.H. Chan School of Public Health, who conducted a long-term study on more than 63 million older Americans, have found a significant link between air pollution and several neurological disorders, including Alzheimer’s, Parkinsonism, among others.
The study, published online Monday in The Lancet Planetary Health, was also conducted with researchers at Emory University’s Rollins School of Public Health and Columbia University’s Mailman School of Public Health.
The new research is among the first nationwide analysis and evaluations of the association between fine particulate (PM2.5) pollution and neurological disorders in the United States.
The researchers compared the data with previous studies of air pollution and neurodegenerative disorders.
Co-lead author of the study Xiao Wu, who is a doctoral student in biostatistics at Harvard Chan School, said, “The 2020 report of the Lancet Commission on dementia prevention, intervention, and care has added air pollution as one of the modifiable risk factors for these outcomes.”
“Our study builds on the small but emerging evidence base indicating that long-term PM2.5 exposures are linked to an increased risk of neurological health deterioration, even at PM2.5 concentrations well below the current national standards,” he added.
The investigators looked at hospital admissions data from more than 63,000,000 Medicare patients from 2000 to 2016. They found that there was a 13% increased risk of hospitalization with Parkinson’s disease and Alzheimer’s disease for each 5 mcg per cubic meter of air (μg/m3) increase in annual PM2.5 concentrations.
The findings suggest that air pollution could play a significant role in increasing the risk of neurodegenerative disorders, such as Parkinson’s and Alzheimer’s or other types of dementias.
The study also found that the risk was particularly high among white people, urban populations, and women. The risk for the first-time hospitalization with Parkinson’s was high among older adults in the northeastern U.S., while for Alzheimer’s, the risk was among older adults in the Midwest. Co-senior author of the study Antonella Zanobetti of Harvard T.H. Chan School of Public Health said, “Our U.S.-wide study shows that the current standards are not protecting the aging American population enough, highlighting the need for stricter standards and policies that help further reduce PM2.5 concentrations and improve air quality overall.”