ST. PAUL, Minn., July 24 (UPI) -- British researchers said Thursday they've found "significant evidence" of a long-suspected link between air pollution and dementia after studying data from nearly 30 million people across four continents.
The authors of a paper published in The Lancet Planetary Health reviewed data compiled from 32 studies that involved more than 29 million participants, mostly from high-income countries in Europe, North America and Asia, as well as Australia, to "provide more robust overarching conclusions" about the suspected connection.
After crunching the numbers from those studies, University of Cambridge researchers said they had identified a "positive and statistically significant association" between dementia and long-term exposure to three types of air pollutants: fine particulate matter with diameters of 2.5 microns or less, nitrogen dioxide, and soot from sources such as vehicle exhaust emissions and burning wood.
They also concluded the risks of dementia go up as the levels of exposure increase, especially for the tiny particulate matter, which is so small it can be inhaled deeply into the lungs. For such "PM2.5," every 10 micrograms per cubic meter (μg/m³) of long-term exposure increases an individual's relative risk of dementia by 17%, they found.
