Chemicals found in pollution could increase inflammation in the body, which is known to affect one's risk for several conditions

Of all the myriad variables that increase one's risk for developing type 2 (adult onset) diabetes -- smoking, being overweight, having a larger waistline -- air pollution is not one we usually think of. But newer studies are suggesting environmental risk factors for diabetes: A new one finds that living in an area with more traffic pollution could increase one's risk, particularly in people who are healthier to begin with.

Researchers followed 52,000 city-dwellers in Denmark over a period of ten years. During this time, about 2,800 participants (5.5 percent), who were 50-65 when the study started, developed diabetes. The researchers also measured nitrogen dioxide levels, as a marker of traffic pollution, around the homes of the participants.

The classic variables associated with diabetes were found in this study, as one would expect: advanced age, weight, smoking status, fat intake, blood pressure, cholesterol, and alcohol intake were all linked to greater risk of diabetes.

But beyond these variables, the researchers also found that living in areas with more pollution was correlated with an increased diabetes risk -- but only slightly, at about four percent. The link was "borderline significant," according to the researchers. It was, however, stronger for people who were in better overall health, and for women. For example, in non-smokers who lived in high pollution areas, the risk for diabetes rose to 12 percent. A 10 percent increase in risk was found for physically active people. Women were another group for whom traffic pollution appeared to have an especially large effect.