Air pollution linked with higher risk of dementia: Study
What's the story
Even a small increase in the levels of fine particle pollution (PM2.5) is associated with a greater risk of dementia for people living in those areas, shows a study conducted in the US.
Researchers at the University of Washington used data from two large, long-running projects—one that began in the 1970s measuring air pollution and another on dementia risk factors that started in 1994.
Link
Researchers identified a link between PM2.5 and dementia
The researchers identified a link between PM2.5 or particulate matter 2.5 micrometers or smaller and dementia.
"We found that an increase of one microgram per cubic meter of exposure corresponded to a 16% greater hazard of all-cause dementia. There was a similar association for Alzheimer's-type dementia," said study lead author Rachel Shaffer, who conducted the research as a doctoral student at the university.
Study
The study looked at over 4,000 Seattle-area residents
The study, published in the journal Environmental Health Perspectives on August 4, looked at over 4,000 Seattle-area residents enrolled in the Adult Changes in Thought (ACT) Study.
Of those residents, the researchers identified more than 1,000 people who had been diagnosed with dementia at some point since the ACT Study began in 1994.
Identification
Here's how researchers conducted the study
Once a patient with dementia was identified, researchers compared the average pollution exposure of each participant leading up to the age at which the dementia patient was diagnosed.
For instance, if a person was diagnosed with dementia at 72 years old, the researchers compared the pollution exposure of other participants over the decade prior to when each one reached 72.
Key risk factors
Air pollution now recognized to be among key risk factors
The researchers found that just a one microgram per cubic meter difference between residences was associated with a 16% higher incidence of dementia.
While there are many factors such as diet, exercise, and genetics associated with the increased risk of developing dementia, air pollution is now recognized to be among the key potentially modifiable risk factors, the researchers said.
Latest results
Reducing exposure to air pollution could help reduce dementia
The latest results add to this body of evidence suggesting air pollution has neurodegenerative effects and that reducing people's exposure to air pollution could help reduce the burden of dementia.
"Over an entire population, a large number of people are exposed. So, even a small change in relative risk ends up being important on a population scale," said Shaffer.