Research at the University of Southern California has uncovered a link between air pollution and elevated risk of Type 2 diabetes among overweight Latino children.
Type 2 diabetes affects 9.3 percent of the American population — a percentage that is expected to increase in coming years, according to the CDC. Poor eating habits, lack of exercise and genetics are widely recognized as playing roles in this epidemic, but the USC study builds on previous research that points to another possible culprit: air pollutants.
“It has been conventional wisdom that this increase in diabetes is the result of an uptick in obesity due to sedentary lifestyles and calorie-dense diets,” Frank Gilliland, senior author of the study and a Professor of Preventive Medicine at the Keck School of Medicine, stated in a news release regarding his team’s findings. “Our study shows air pollution also contributes to Type 2 diabetes risk.”
Published in the American Diabetes Association’s journal Diabetes, the study followed 314 obese and overweight Latino children in Los Angeles who were between the ages of 8 and 15. The children lived in areas that the EPA has determined to have excess levels of nitrogen dioxide as well as a type of pollution called particulate matter 2.5, which is produced by power plants and automobiles.
Every year, the participants fasted before visiting the Childhood Obesity Research Center at USC to have their glucose and insulin levels measured. Using these tests, researchers determined the efficiency with which certain pancreatic cells were producing insulin.
Adjusting for body fat and socioeconomic status, researchers found the participants were less responsive to insulin. Two-hour glucose tests revealed they had about 36 percent more insulin than normal levels, a hallmark of that diminished responsiveness. By the time the children reached age 18, the cells were functioning at 13 percent reduced efficiency, making the participants more likely to later develop Type 2 diabetes. In some cases, the effect of long-term exposure to high levels of pollution was so drastic it exceeded that of a 5 percent weight gain.
“Exposure to heightened air pollution during childhood increases the risk for Hispanic children to become obese and, independent of that, to also develop Type 2 diabetes,” Michael Goran, Co-director of the Diabetes and Obesity Research Institute at the Keck School of Medicine, stated in the release.
The results reinforce those of other studies that examined the link between air pollution and diabetes, but this is the first study to follow children over an extended period of time — 3.5 years on average.
The researchers say future studies will include participants of normal weight and will collect dietary and activity data as well.