Dementia and air pollution: is there a link?

Dementia is one of the world’s most serious problems. It is the number one cause of death in England and Wales and the fifth worldwide. In the United States, Alzheimer’s disease, described by the Center for Disease Control as “a deadly form of dementia,” is the sixth leading cause of death. According to WHO, in 2015 there were more than 46 million people with dementia worldwide, in 2016 this figure increased to 50 million. This number is expected to rise to 2050 million by 131,5.

From the Latin language “dementia” is translated as “madness”. A person, to one degree or another, loses previously acquired knowledge and practical skills, and also experiences serious difficulties in acquiring new ones. In the common people, dementia is called “senile insanity.” Dementia is also accompanied by a violation of abstract thinking, the inability to make realistic plans for others, personal changes, social maladjustment in the family and at work, and others.

The air we breathe can have long-term effects on our brains that can eventually lead to cognitive decline. In a new study published in the journal BMJ Open, researchers tracked dementia diagnosis rates in older adults and levels of air pollution in London. The final report, which also assesses other factors such as noise, smoking and diabetes, is another step towards understanding the link between environmental pollution and the development of neurocognitive diseases.

“While the findings should be viewed with caution, the study is an important addition to the growing evidence for a possible link between traffic pollution and dementia and should encourage further research to prove it,” said study lead author and epidemiologist at St George’s University London, Ian Carey. .

Scientists believe that the result of polluted air can be not only cough, nasal congestion and other non-fatal problems. They have already linked pollution to an increased risk of heart disease and stroke. The most dangerous pollutants are tiny particles (30 times smaller than a human hair) known as PM2.5. These particles include a mixture of dust, ash, soot, sulfates and nitrates. In general, everything that is released into the atmosphere every time you get behind the car.

To find out if it could damage the brain, Carey and his team analyzed the medical records of 131 patients aged 000 to 50 between 79 and 2005. In January 2013, none of the participants had a history of dementia. The researchers then tracked how many patients developed dementia during the study period. After that, the researchers determined the average annual concentrations of PM2005 in 2.5. They also assessed traffic volume, proximity to major roads, and noise levels at night.

After identifying other factors such as smoking, diabetes, age, and ethnicity, Carey and his team found that patients living in areas with the highest PM2.5 the risk of developing dementia was 40% higherthan those who lived in areas with lower concentrations of these particles in the air. Once the researchers checked the data, they found that the association was only for one type of dementia: Alzheimer’s disease.

“I’m very excited that we’re starting to see studies like this,” says George Washington University epidemiologist Melinda Power. “I think this is especially useful because the study takes into account noise levels at night.”

Where there is pollution, there is often noise. This leads epidemiologists to question whether pollution really affects the brain and whether it is a consequence of long-term exposure to loud noises such as traffic. Perhaps people in noisier areas sleep less or experience more daily stress. This study took into account noise levels during the night (when people were already at home) and found that noise had no effect on the onset of dementia.

According to Boston University epidemiologist Jennifer Weve, the use of medical records to diagnose dementia is one of the biggest limitations to research. These data may be unreliable and may only reflect diagnosed dementia and not all cases. It is likely that people living in more polluted areas are more likely to experience stroke and heart disease, and therefore regularly visit doctors who diagnose dementia in them.

Exactly how air pollution can damage the brain is still unknown, but there are two working theories. First, air pollutants affect the vasculature of the brain.

“What’s bad for your heart is often bad for your brain”Power says.

Perhaps this is how pollution affects the functioning of the brain and heart. Another theory is that pollutants do enter the brain via the olfactory nerve and cause inflammation and oxidative stress directly to the tissues.

Despite the limitations of this and similar studies, this kind of research is really important, especially in a field where there are no drugs that can treat the disease. If scientists can prove this link definitively, then dementia could be reduced by improving air quality.

“We won’t be able to completely get rid of dementia,” Wev warns. “But we could at least change the numbers a bit.”

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