Scientists say they have discovered a particular gene variant in patients with type 2 diabetes that is linked to higher risk of heart disease.

The researchers, from the Harvard School of Public Health in Boston, conducted an analysis of five different studies and have published their findings in the journal JAMA.

This included 1,517 people with coronary heart disease (CHD), alongside 2,671 people without CHD. All participants had type 2 diabetes.

These participants were compared with 737 participants who had CHD but no sign of diabetes, and 1,637 people who had neither CHD nor diabetes.

The researchers tested 2,543,016 genetic variants in the first stage of the analysis to see if there was a link associated with coronary heart disease. Of these, 26 of the genetic variants continued to the second stage, and 3 were brought forward to the third stage.

Of these 3 genetic variants, the researchers found that one on chromosome 1q25 was linked to increased risk of coronary heart disease in the participants who were diabetic.

However, the researchers found no link between this genetic variant and CHD in the participants who did not have type 2 diabetes.

The study authors explain:

The locus is in the region of the GLUL (glutamate-ammonia ligase) gene on chromosome 1q25, and may affect CHD risk by reducing the expression of this gene and affecting glutamate and glutamine metabolism in endothelial cells.

This genetic variant appeared to be specifically associated with CHD in the diabetic population and showed a significant gene-by-diabetes synergism on CHD risk.”

According to the American Diabetes Association, people with diabetes are more than twice as likely to suffer a heart attack or stroke, compared with people who do not have the condition. Additionally, two out of three people with diabetes die from a heart attack or stroke.

But a survey conducted in 2011 of physicians from the American Medical Association Masterfile, revealed that although physicians are aware that heart disease and stroke are the main cause of death in patients with type 2 diabetes, 52% of them underestimate the link between heart disease and diabetes.

The researchers add that previous studies have suggested that genetic factors linked to increased risk of heart disease may be different in patients with type 2 diabetes.

But they say that although this research presents further evidence of this, more studies are needed to determine the biological mechanisms behind the link between the two conditions.

“Further studies are needed to dissect the mechanisms linking this locus to the development and progression of atherosclerosis in diabetes,” the researchers say.

“As part of these efforts, it would be useful to extend the study to type 1 diabetes because this may provide clues about whether the gene X diabetes interaction involves hyperglycemia or instead concerns factors that are specific to type 2 diabetes, such as insulin resistance or some of the genes predisposing to this form of diabetes.”