According to a meta-analysis published in the October 26, 2022, online issue of Neurology®, the medical journal of the American Academy of Neurology, higher exposure to a certain type of traffic-related air pollution known as particulate matter may be connected to an increased risk of dementia. Researchers focused on fine particulate matter, or PM2.5, which is made up of airborne pollutants with a diameter of less than 2.5 millimetres. All known research on air pollution and dementia risk was included in the meta-analysis.
According to research author Ehsan Abolhasani, MD, MSc, of Western University in London, Canada, “as individuals continue to live longer, illnesses like dementia are becoming more widespread, thus detecting and understanding avoidable risk factors is crucial to minimizing the increase of this disease.” The results provide more evidence for enforcing air quality regulations and accelerating the transition from fossil fuels to sustainable energy, the authors write. “Since a report by the World Health Organization showed that more than 90% of the world’s population is living in areas with higher than recommended levels of air pollution.”
The researchers examined 17 studies for the meta-analysis. Participants had a minimum age of 40. More than 91 million people took part in all the studies. 5.5 million of them, or 6%, experienced dementia.
Age, sex, smoking, education level, and other characteristics that may increase or decrease a person’s risk of dementia were taken into account in the investigations.
Researchers analyzed the rates of exposure to air pollution for those with and without dementia and discovered that those without dementia had a lower average daily exposure to fine particle matter air pollutants. Average annual doses of up to 12 g/m3 are deemed acceptable by the U.S. Environmental Pollution Agency (EPA).
Researchers found that the risk of dementia went up by 3% for every one microgram per cubic meter (g/m3) of fine particulate matter.
Our aim is that these results will encourage individuals to actively participate in lowering their exposure to pollution, Abolhasani said, even if our meta-analysis simply demonstrates a connection rather than proving that air pollution causes dementia. People can limit their exposure to pollution by using renewable energy, choosing to live in less polluted areas, and pushing for less pollution from cars in residential areas. This is because people who know that pollution can cause dementia can take steps to limit their exposure.
They also examined exposure to ozone, nitrogen dioxide, and the smog-forming nitrogen oxides but did not discover a noticeably higher risk when these other groups of pollutants were taken into account separately.
The small number of papers that were available on this particular subject was a limitation of the meta-analysis. More research, according to Abolhasani, is required.
