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Air Pollution and Dementia!

Friday, December 21, 2018

New research offers powerful evidence of a link between air pollution and the risk of developing Alzheimers (a form of dementia).

A recent study has found that older women who breathe in air that has been polluted by vehicle exhaust fumes and other fine particulates from other sources are nearly twice as likely to develop dementia. Furthermore, the cognitive effects of air pollution are dramatically more pronounced in women who carry the APOE-e4 gene that puts them at a higher risk of developing Alzheimer's disease.
A recent ten year nationwide study explored the cognitive health of women between the ages of 65-79. It found that those who carry the APOE-e4 gene are nearly three times more likely to develop dementia if exposed to high levels of air pollution than those APOE-e4 carriers who are not exposed to more than low amounts.

While scientists have always linked air pollution to asthma, lung disease and cardiovascular disease, the negative impact of air pollutants on brain health has only recently come to the attention of researchers. The study mentioned provides new insight into how urban smog affects the aging brain.

The research looked at a large population of American women, lab mice, and at brain tissue in microscopic studies to see if there was a link between cognitive decline and the small particles of pollution that are emitted by motor vehicles, power plants, and the burning of biomass products such as wood.

All three methods suggested that exposure to high levels of fine air pollutants increases disorientation and memory loss - two classic early signs of dementia.

A study published in 2011 found that those who live near heavily trafficked roads are more at risk of developing dementia or having a stroke than those who do not. In 2012, several well known studies found that air pollutants induced cell death, inflammation, and the buildup of beta amyloid protein in the brains of mice.

New studies verify these findings. These studies estimate that before the EPA (Environmental Protection Agency) decided to set new air pollution standards in 2012, around 21% of new dementia cases and accelerated cognitive decline could be attributed to air pollution.

Air pollution has been found to be on a steady decline since air controls were implemented in auto emissions and manufacturing in the late 1900s. However, even though there may have been a decline in the levels of air pollution over the last fifteen or twenty years, it's still not clear whether the current standards are safe for aging brains or those brains that are genetically vulnerable to Alzheimer's.

Suggestion:  Stay inside when the air is particularly dirty. Walk early or after rush hour traffic has slowed down in the evenings.

Spencer Thornton, MD