Genetic Testing No Real Help in Predicting Type 2 Diabetes

Nov. 20 -- WEDNESDAY, Nov. 19 (HealthDay News) -- Testing for 18 different gene variations associated with type 2 diabetes was no better at predicting a person's risk for the blood sugar disease than a doctor's assessment, researchers report.

The news is both encouraging and discouraging.

"The genomics revolution is here. You can be tested for disease risk," said Dr. James Meigs, lead author of one of two studies published in the Nov. 20 issue of the New England Journal of Medicine. "In the framework of diabetes, the more risk genes you have, the higher risk you are. We didn't really know before that you could add up risks across genes."

"But, we don't know enough about diabetes genetics to make a recommendation for widespread testing," added Meigs, an assistant professor of medicine at Harvard Medical School and Massachusetts General Hospital, in Boston. "For adults, the information you can get at a check-up with your doctor tells you everything you need to know for your risk of diabetes. In youth, genetic testing could be useful. The value of any of this is going to lie in the question of how much knowing genetic information would cause you to change lifestyle factors."

Incorporating other gene variants, however, might fine-tune such genetic screening.

"More work needs to be done. The kind of genotypes they have studied are only 18. That's very insufficient," said Rajat Sethi, an assistant professor of pharmaceutical sciences with the Texas A&M Health Science Center Irma Lerma Rangel College of Pharmacy in Kingsville. "I think more genetic variations need to be studied. This is a good approach."

Many risk factors for type 2 diabetes are well known, including, notably, a family history of the disease, as well as poor nutrition, lack of exercise and carrying too much weight. Experts believe that both genetic and environmental factors -- such as diet and exercise -- and an interplay between the two contribute to developing diabetes.

Meigs and his colleagues examined 18 gene mutations associated with type 2 diabetes in 2,377 people participating in the Framingham Offspring Study, a three-decade-long study. Each gene conferred a 5 percent to 37 percent increased risk of developing diabetes, the researchers said.