Air Pollution – A Big Contributor to Dementia

Dr. Elissa Wilker, a researcher in the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess Medical Centre, said: Our findings suggest that air pollution is associated with insidious effects on structural brain aging, even in those, who are free from dementia and stroke.”

The study found that those living near major roads suffered cerebral shrinkage, brain aging, thereby increasing their dementia risk.

The study, published in the journal Stroke, found that small air pollution increases were sufficient to increase the risks. The participants also had a 46 percent higher risk of silent strokes. We know that silent strokes increase the risk of overt strokes and of developing dementia.

Now a study from Canada has shown a correlation between dementia and exposure to heavy automobile traffic. The study examined the medical records of 6.5 million Ontario residents aged 20 to 85. The researchers looked at the occurrence of three major neurological disorders – dementia, Parkinson’s disease, and multiple sclerosis – in the context of where people lived.

The results showed that people who live within 50 meters of a busy street have a 7 percent higher incidence of dementia than those who live at least 200 meters away from heavily traveled roads. The risk of dementia decreased 4 percent for those who lived between 50 and 100 meters away from high-traffic areas. This appears to confirm the link.

Is Chronic Inflammation Responsible For It? –

Air pollution is a complex mixture of particulate matter, gases, and organic compounds present in outdoor and indoor air. The researchers have found that particulate matter in air pollution stimulates inflammation in the lungs. The products of that inflammation spill over into the body’s circulation, traveling to fatty tissue to promote inflammation further and causing vascular dysfunction. Though the entire mechanism has not been identified fully, there is evidence now to the effect that air pollution exposures are linked to neuroinflammation and neuropathology.

Alzheimer’s disease (AD) is the most common form of dementia. It is characterized by extracellular deposition of a specific protein, beta-amyloid peptide fibrils, and is accompanied by extensive loss of neurons in the brains of affected individuals. Neuro-inflammation has been known to play a critical role in the pathogenesis of chronic neurodegenerative disease in general and in AD in particular.

Although the pathophysiologic mechanism is not fully established, inflammation appears to be involved. So, there is a new understanding of the important relationship between inflammation and dementia.

The researchers have determined that higher concentrations of fine particulate matter in air pollution are linked to a faster thickening of the inner two layers of the common carotid artery, an important blood vessel that provides blood to the head, neck, and brain. This serves as an indicator of how much atherosclerosis is present in the arteries throughout the body.

Vascular dementia happens when part of the brain doesn’t get enough blood carrying the oxygen and nutrients it needs due to atherosclerosis. This results in vascular cognitive impairment typically occurring after a series of minor strokes.

Several studies show that chronic inflammation caused due to air pollution is responsible for causing dementia, which seems to be accelerated faster in people prone to the disease.

The Final Thoughts –

Over the past 30 years, researchers have unearthed a wide array of health effects, which are believed to be associated with air pollution exposure.

It has been found that pollution is one of the biggest global killers, affecting over 100 million people. Whether one likes it or not, pollution – outdoor and indoor – is one the most ignored concept in the modern world.

As we all know, air pollution is a huge problem, becoming bigger and bigger day by day. At times, we feel that it has become too big for us to control. But an effort, howsoever small, made by anyone in the direction of reducing air pollution will be laudable. We will have to work in tandem with all agencies – national and international – to help reduce air pollution