A new study from Johns Hopkins Hospital and Johns Hopkins University School of Medicine links air pollution to a higher risk of Lewy body dementia (LBD) in the US. LBD is a term used to refer to both dementia with Lewy bodies and Parkinson’s disease with dementia. Researchers analysed data from more than 56 million Medicare beneficiaries over the age of 65, finding that people living in areas with higher levels of fine particle pollution (PM2.5) faced an increased risk of hospitalisation with LBD. This link was less pronounced for Parkinson’s disease without dementia.
In follow-up experiments, mice exposed to chronic PM2.5 pollution developed brain changes characteristic of LBD, including increased neurodegeneration and brain atrophy, suggesting a possible biological pathway behind the association. Jacqui Hanley, Head of Research
Funding at Alzheimer’s Research UK, said: “Air pollution is not just an environmental issue – it’s a serious and growing threat to our brain health. We know that if no-one were exposed to air pollution, there would be three fewer cases of dementia for every 100 people who develop it now.
“This new research, involving over 50 million Americans, found that long-term exposure to air pollution was linked to a higher risk of developing Lewy body dementia (LBD), the third-most common form of dementia.
“But we don’t know how air pollution causes this increased risk,” she continued. “This paper suggests the main protein involved in LBD in the brain is affected by higher levels of particle matter found
in areas of high air pollution. Previous studies have shown that air pollution is linked to many health conditions like heart disease, which in turn increase our risk of dementia, so these findings are particularly interesting because they provide insight into how air pollution may impact underlying disease proteins, albeit in mice.
“However, there are some limitations to the study. In dementia, changes in the brain can happen decades before symptoms appear. This study looked at air pollution data across the US from 2000 to 2014, so more research is needed to understand the impact of air pollution across people’s entire lifespan, and how pollution exposure over time may increase the risk of harmful effects to our brain health. Larger, population-wide studies are also vital to explore how other dementia risk factors, such as education and ethnicity, interact with air pollution to shape dementia risk.”
