Study air pollution can significantly increase the risk of dementia

Doctors are studying the effects of air pollution on our brains
Unfortunately, air pollution is widespread in today's society in most Western countries. It has long been clear that increased air pollution does not just cause lung disease. Researchers now found that air pollution can also increase the risk of dementia.

Researchers at the University of Southern California (USC) in the United States found in an investigation that airborne pollution may increase the risk of dementia. The physicians published the results of their study in the journal "Translational Psychiatry".

In western industrialized countries, there is often a high level of air pollution. The polluted air causes humans to take on harmful microscopic particles that can increase the risk of dementia in those affected. (Image: Ralf Geithe / fotolia.com)

Small particles from the air can penetrate into the brain
Air pollution is widespread in the Western world. Power plants and cars release tiny particles into the air. These are then inhaled by humans. The researchers explain that such particles can also penetrate into the brain. There they increase the risk of dementia. Air pollution is as dangerous to the aging brain as tobacco consumption, says author Caleb Finch of the University of Southern California.

Physicians expose mice to air pollution
For the study, scientists collected samples of airborne particles using technology developed by university engineers. Thereafter, female mice were exposed to corresponding air pollution.

Study investigates neurodegenerative health effects
The new method makes it possible for normal air to be selectively converted into polluted air with certain impurities. For example, pure air becomes polluted air like on highways or in heavily polluted cities like Beijing, explains the author Professor Constantinos Sioutas. "We then use such samples to test the exposure and evaluate negative neuro-developmental effects or neurodegenerative health effects," adds the expert.

In some laboratory mice, air pollution has led to 60 percent more plaques
The mice carried in themselves a specific genetic variation, this is referred to as APOE4 gene, the researchers explain. APOE4 increases the risk for Alzheimer's. After exposure to air pollution for a period of 15 weeks, the mice had 60 percent more so-called amyloid plaques. These accumulations of protein are associated with the degenerative disease, the scientists explain. For their study, the researchers analyzed data from more than 3,600 American women between the ages of 65 and 79 years. None of the participants suffered from dementia at the beginning of the study.

Air pollution massively increases the risk of cognitive decline
Taking into account variables such as race, ethnicity, lifestyle and health, the researchers found that older women from areas with high levels of air pollution have a 81 percent increased risk of cognitive decline. Such women also develop 92 percent more signs of dementia, including Alzheimer's disease. The negative effects of air pollution on the brain were particularly strong among women carrying the APOE4 gene, the authors add.

Air pollution could account for about 21 percent of all cases of dementia
When their results were extended to the general population, the authors of the study calculated that air pollution could account for about 21 percent of all cases of dementia.

What do the microscopic particles in the human body do??
Microscopic particles are generated by fossil fuels. The particles enter the body directly through the nose and then into the brain. Cells in the brain treat these particles as invaders and react with inflammatory reactions that, over time, potentiate Alzheimer's disease and promote disease, the researchers explain.

Air pollution in mice damages neurons in the hippocampus
The current study provides the first scientific evidence that a so-called Alzheimer's risk gene may react with particles in the air. This then leads to accelerated aging of the brain, says author Professor Jiu-Chiuan Chen. The experimental data showed that the corresponding particles in mice can damage neurons in the hippocampus. This could make the so-called memory center more susceptible to brain aging and increase the risk of Alzheimer's, adds the expert. (As)