Gene Linked to Heart Disease in Diabetics

A new study by a team of researchers at Harvard Medical School found a correlation between a genetic variant and a higher risk for coronary artery disease among people with diabetes and poor glucose control.

Previous studies had found a relationship between the variant on chromosome 9p21 and coronary artery disease in the general population.

This new study, which was published in the November 26 issue of the Journal of the American Medical Association, was the first of its kind because it focused on people with diabetes, rather than the general population.

“Diabetes is one of the strongest cardiovascular risk factor, so we were interested in understanding whether the presence of diabetes ‘trumped’ the genetic effect,” said Medical School professor Alessandro Doria, the director of the Genetics Core at Harvard-affiliated Joslin Diabetes Center.

According to Doria, diabetes accounts for many coronary artery disease cases.

“Other factors of coronary artery disease include smoking, hypertension, and high cholesterol,” Doria said. “Over the years these factors have gone down while diabetes has not. In fact, diabetes rates are increasing.”

The study, which included more than 1,500 type 2 diabetes patients over several years, surprised both Doria and his colleagues in its conclusion about the gene variant’s impact.

“We were surprised to see that the effect of the 9p21 variant on coronary artery disease was actually greater, rather than smaller, among individuals with diabetes,” Doria said.

“We found that the greater effect was due to a synergism between the genetic variant and hyperglycemia,” Doria said. “Diabetic individuals who had both factors had a risk of coronary artery disease up to eight times higher than that of diabetic subjects who have neither factor.”

The study’s findings, while at an early stage, await to be confirmed by even more research.

“We need to see if the data can be generalized. If we can see the mechanisms at the molecular level, we’ll be able to identify people at high risk in order to be very aggressive in prevention of coronary disease,” Doria said.

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