Lead author Qinghua Sun of Ohio State University says exposure levels for the animals subjected to polluted air resemble the fine-particulate pollution that can be found in U.S. urban areas.
Sun and colleagues fed the mice either a normal diet or a high-fat diet and exposed them to either filtered air or air containing at least seven times more fine particulates than the ambient air in Columbus, Ohio.
After exposing the mice to polluted or filtered air for 10 weeks, researchers analyzed the mice for risk factors associated with obesity and insulin resistance -- the hallmark of type 2 diabetes, Sun says.
The researchers say the mice on the high-fat diet gained much more weight than those on the normal diet, but mice exposed to polluted air and eating the normal diet had more significant elevations in glucose in the blood than the normal-diet mice that breathed clean air.
The mice exposed to pollution also showed more signs of insulin resistance -- when the presence of insulin does not initiate the transfer of glucose from the blood into the tissues, where it is used for energy.
The findings are published in the journal Arteriosclerosis, Thrombosis and Vascular Biology.