August 15, 2023 – About 188,000 latest cases of dementia every year might be attributable to exposure to air pollution, in line with a brand new study from the University of Michigan. Older people living in places with high levels of air pollution from agriculture or wildfires are at particularly high risk.
The study was published on Monday within the magazine JAMA Internal Medicine. It linked 18 years of health data with the extent of air pollution at the house address of every of the nearly 28,000 people studied. None of them had dementia at the beginning of the study, their average age was 61, and 57% were women.
Of all of them, 15% developed dementia inside a median 10-year period, but those that lived in areas with high levels of pollution had an 8% higher risk of developing dementia. (Dementia refers to a gaggle of brain disorders that affect pondering, memory, language and problem solving. Alzheimer's disease is probably the most common type of dementia.)
The researchers examined dementia risk levels based on various kinds of pollution, including exposure from agriculture, traffic, coal combustion and wildfires.
The best risk of developing dementia was observed in people living in areas with high levels of air pollution from agriculture or wildfires. Exposure to agriculture was related to a 13% increased risk of dementia, and exposure to wildfires was related to a 5% increased risk.
“In our study, we used a sophisticated prediction model that incorporates information about the chemical transformations and dispersion of pollutants from different sources to estimate source-specific levels of fine particulate air pollution at participants' home addresses,” said researcher Boya Zhang, a doctoral student specializing in studying the cognitive effects of pollutants, in an announcement. “This approach is advantageous because it takes into account not only pollution emitted directly from a source, but also pollution produced by reactions with other chemicals in the air.”
Particles from wildfires are so small that they'll enter the brain directly through the nose or otherwise breach the blood-brain barrier. The findings are vital because exposure to neurotoxic air pollution is taken into account “modifiable,” meaning people's exposure to pollution may be reduced or pollution itself may be reduced.
“These findings come at a time when the incidence of wildfire smoke is increasing in our communities,” said researcher Sara Adar, ScD, associate professor of epidemiology, in a opinion“Our data suggest that in addition to the more obvious health effects of wildfire smoke, such as throat and eye irritation and difficulty breathing, smoke on days with high levels of smoke may also have a negative impact on our brains.”
“Our results show that reducing particulate matter pollution in the air, even in a relatively clean country like the United States, can reduce the number of people who develop dementia in old age,” Adar said.