Diabetes and heart failure have been linked time and again, due to the body’s failure to control blood sugar levels, but new research from the Johns Hopkins Bloomberg School of Public Health suggests a novel mechanism by which risks increase.

Cardiovascular disease is the leading cause of death among diabetics. When the pancreas can’t produce enough insulin to match rising blood glucose levels, the excess sugar taxes the heart’s ability to pump. Sugars develop into plaques, which can lead to atherosclerosis, or a hardening of the arteries. But now researchers suggest this sugar surplus inflicts a different kind of damage, namely, tiny repeated blows to the muscle over time.

"It puts what we know about heart damage in diabetes on its head," said study leader and associate professor of epidemiology Dr. Elizabeth Selvin in a statement.

Selvin and her colleagues collected data on more than 9,000 people as part of the Atherosclerosis Risk in Communities Study. They were checking for levels of a specific protein, known as troponin, in people’s blood. And rather than use traditional measuring methods, they used a method not currently available in the United States, known generally as an assay, which looked at troponin levels 10 times closer than standard blood checks.

Looking at two points, two years apart, they found diabetics were two-and-a-half times more likely to have elevated troponin levels than the average person. After 14 years of follow-up data, the same people were six times more likely to die of heart failure and four times more likely to die of a heart attack. People with prediabetes were also at increased risk.

The risks incurred by elevated blood sugar levels are decidedly hard to track, which is what makes them so dangerous. Normally, diabetics who show signs of a heart complication are given statins to lower their cholesterol. But now there is an entire swath of people for whom statins would offer no benefit whatsoever, Selvin says.

"Even though there may be no symptoms yet, our research suggests there is microvascular damage being done to the heart which is leading to heart failure and even death."

The upshot for people with diabetes is to keep heart health as big a priority as blood glucose monitoring and overall dieting. Though the exact mechanism remains somewhat foggy, the advice Selvin and her team give suggests diabetics should stay cognizant of the risks their hearts face. "It looks like diabetes may be slowly killing heart muscle in ways we had not thought of before,” she said.

Prior research into diabetes and heart complications has found a group of fat metabolites tend to change in the blood of diabetics. The metabolites could, in theory, act as a biomarker to detect a person’s risk for the disease. Scientists are also at work on developing a blood test to predict a person’s continuous risk level as time passes.

Source: Selvin E, Lazo M, Chen Y, et al. Diabetes, Pre-Diabetes and Incidence of Subclinical Myocardial Damage. Circulation. 2014.