Exposure to bad air increases obesity risk

Exposure to highly polluted air for three-to-eight weeks may lead to an increase in weight, breathing problems and metabolic dysfunctions, showed a recent study.

"Since chronic inflammation is recognized as a factor contributing to obesity and since metabolic diseases such as diabetes and obesity are closely related, our findings provide clear evidence that chronic exposure to air pollution increases the risk for developing obesity," said senior author Junfeng "Jim" Zhang from Duke University in the US.

"If translated and verified in humans, these findings will support the urgent need to reduce air pollution, given the growing burden of obesity in today's highly polluted world," Zhang added in a paper published in the Journal of the Federation of American Societies for Experimental Biology (FASEB).

Researchers placed pregnant rats and their offspring in two chambers, one exposed to outdoor air and the other containing an air filter that removed most of the air pollution particles.

After 19 days, according to the findings, lungs and livers of pregnant rats exposed to the polluted air were heavier and showed increased tissue inflammation. These rats had 50 percent higher LDL (bad) cholesterol and 97 percent higher total cholesterol.

Their insulin resistance level, a precursor of Type-2 diabetes, was also higher.

At eight weeks old, female and male rats exposed to the pollution were 10 percent and 18 percent heavier respectively than those exposed to clean air.

The results of this study are consistent with other studies that show air pollution induces oxidative stress and inflammation in the organs and circulatory system.

The findings also echo previous studies linking air pollution with increased insulin resistance and altered fat tissue.