Elevated Blood Sugar a Cardiovascular Disease Risk Not Linked to Cholesterol Levels

Individuals with prediabetes and diabetes are at high risk for cardiovascular events such as myocardial infarction that can be predicted by elevated levels of troponin T.

The protein troponin T binds to tropomyosin and helps position it on actin, and with the rest of the troponin complex modulates contraction of striated muscle. In patients with stable coronary artery disease, troponin T concentrations have been found to be significantly associated with the incidence of cardiovascular death and heart failure.

In a recent study, investigators at Johns Hopkins University (Baltimore, MD, USA) reported that individuals with pre-diabetes or diabetes who displayed elevated levels of troponin T were approximately six times more likely to experience a cardiovascular incident than were those with normal blood sugar levels.

These findings were obtained by using a highly sensitive troponin T assay to determine levels of the protein in blood samples from more than 9,000 participants in the Atherosclerosis Risk in Communities Study (ARIC) at two time points. At the first measurement those with diabetes were two and a half times more likely to have elevated troponin levels than those without. At follow-up 14 years later, diabetics with elevated troponin were seen to be six times more likely to develop heart failure and four times more likely to have a heart attack.

Due to the link between cardiovascular disease and diabetes, patients with newly diagnosed diabetes are typically prescribed a cholesterol-lowering statin. "However, this study suggests that there may be people with diabetes whose heart risk may have nothing to do with cholesterol," said first author Dr. Elizabeth Selvin, associate professor of epidemiology at Johns Hopkins University. "Statin treatment may not be sufficient to prevent damage to the heart in people with diabetes. 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. It puts what we know about heart damage in diabetes on its head. It looks like diabetes may be slowly killing heart muscle in ways we had not thought of before."

The study was published in the August 2014 online edition of the journal Circulation.

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