That Happened!

New York - Genetic testing can not determine a person’s risk for developing type 2 diabetes any better than traditional methods, such as doctor’s assessments, according to two studies published Wednesday in the New England Journal of Medicine.

“We don’t know enough about diabetes genetics to make a recommendation for widespread testing,” said Dr. James Meigs, lead author of the first study and assistant professor of medicine in Harvard Medical School.

Both clinical trials studied gene variants - 18 in the first study, 16 in the second - in its participants in order to determine if the genes were associated with a risk of diabetes. These studies were developed in an attempt to find better ways of predicting, and therefore preventing, type 2 diabetes.

In the first study, Dr. Meigs and his team of researchers studied the database of the Framingham Offspring Study, which included the blood samples of more than 2,300 participants who were followed for 28 years. Eleven percent, or 255 of the study’s subjects, developed type 2 diabetes during the course of the study.

Each research subject was assigned a genotype score based on the number of genetic variants they had; this score was then compared to other known high-risk factors, such as family history, to determine which variants could predict diabetes risk. Less than 4% of the Framingham Offspring Study participants were reclassified as having higher or lower risk for diabetes based on their genotype score.

The second study, headed by Valeriya Lyssenko, MD, of Sweden’s Lund University, found similar results by studying the Swedish Malmö Preventive Project and the Botnia study in Finland, which included data from almost 19,000 subjects. This study followed participants, from Finland and Sweden, for an average of 23 years. Of the 16 genetic variants studied, 11 were linked to diabetes risk.

Both studies concluded that identification of genetic variants have little impact on an eventual diagnosis of diabetes.

Stronger, and more conventional, predictors of diabetes include family history, smoking, diet, lack of exercise, and impaired glucose tolerance.

Yet, Dr. Meigs still recommends gene testing, operating under the assumption that it will encourage people to change lifestyle habits and in turn reduce the risk of developing diabetes.