Study in young mice finds link between air quality and likelihood of disease
While poor diet and lack of exercise are thought to be the leading causes of diabetes, exposure to polluted air early in life can actually lead to the disease regardless of diet, according to new Ohio State University research. Results from the first of its kind animal study appear in the December issue of the journal Arteriosclerosis, Thrombosis, and Vascular Biology.
Approximately 23 million Americans struggle with diabetes,* but experts warn that by the year 2050 - that number could double or possibly triple.*
To determine the diabetes-air pollution link, Ohio State researchers exposed young mice on both normal and high-fat diets to either filtered air or air with at least seven times more fine-particulate air pollution than the air in their Columbus, Ohio laboratory.
Their results were surprising: Mice placed in air with higher air pollution had larger and more fat cells in their abdominal area and had higher blood sugar levels than mice eating the same diet but breathing clean air. In other words, the mice placed in higher air pollution but with the same diet became pre-diabetic.**
“This is one of the first, if not the first, study to show that these fine particulates directly cause inflammation and changes in fat cells, both of which increase the risk for Type 2 diabetes,”
said Dr. Qinghua Sun, an associate professor of environmental health sciences at Ohio State University and lead author of the study.
Researchers exposed the mice to the polluted air for six hours a day, five days a week for 10 weeks beginning when the animals were three weeks old. This time frame roughly matches the
toddler years to late adolescence in humans.
The highly polluted air the mice breathed in the study represents the air quality of many Asian cities, where pollution often goes unchecked. While those levels are higher than levels here, it’s still an issue to consider, study authors suggest.
“Pollutants tend to travel,” says Dr. Sanjay Rajagopalan, senior author of the study and the John W. Wolfe Professor of Cardiovascular Medicine at Ohio State. “Large clouds of dust, for instance, can be transported across oceans and can wind up in the western seaboard of the United States from China.”
Researchers say studies will begin soon in China to determine the link between air pollution and diabetes in humans. In the meantime, they stress that diet and exercise should still be considered the most crucial risks in diabetes, but learning more about air pollution and its effects could help curb the growing number of cases.
Air pollution’s tie to the development of diabetes could explain something for Crystal Tubbs, 34, of Dublin, Ohio, who was puzzled by her diagnoses of both Type 1 and Type 2 diabetes.
“Nobody in my family had or currently has diabetes, so it really was quite surprising,” says Tubbs, who has always eaten right and exercised. Tubbs, now pregnant with her third child, checks her blood sugar between 10 and 12 times a day keep her diabetes under control. She agrees with Ohio State researchers in her assertion that the more we learn now, the more proactive we can be in the future.
“If you knew that environmental triggers could put yourself at risk or your children at risk for developing a disease, certainly you would take every precaution to avoid them.”
*Number of Americans with Diabetes Projected to Double or Triple by 2050, Centers for Disease Control and Prevention, October 2010. Online at: http://www.cdc.gov/media/pressrel/2010/r101022.html
**Effect of Early Particulate Air Pollution Exposure on Obesity in Mice. Role of p47 phox, Arteriosclerosis, Thrombosis, and Vascular Biology, September 2010. Online at: http://atvb.ahajournals.org/cgi/reprint/30/12/2518