Leptin augers heart attack, diabetes?

Although leptin is known as the obesity hormone, a new report hints that it may play a role in heart disease as well.

Francisco Leyva, a cardiologist at Charing Cross Hospital in London, and his colleagues conducted a study of 74 healthy men. The researchers found that men with the highest blood concentrations of leptin were more likely to suffer from insulin resistance, a silent condition known to increase the risk of type 2 diabetes, a sugar-processing disorder.

Leyva's study appears in the June 12 Arteriosclerosis, Thrombosis, and Vascular Biology.

In people with insulin resistance, cells respond sluggishly to insulin's message to sop up blood sugar. The result is an excess of sugar in the bloodstream. Previous research has linked insulin resistance to a toxic process that can lead to clogged arteries and heart attacks (SN: 9/16/89, p. 184).

Some researchers believe leptin may have a link to type 2 diabetes. Robert V. Considine of Indiana University School of Medicine in Indianapolis has examined sugar metabolism in human fat tissue. At the June American Diabetes Association meeting in Chicago, he presented preliminary evidence that leptin may help control blood sugar concentrations.

Leyva suggests that leptin measurements might also serve to identify people who are at high risk of heart disease despite having none of the traditional factors associated with it, such as high blood cholesterol.

"Cholesterol is a poor predictor of heart disease," he notes, adding that people with blood cholesterol values in the normal range can have heart attacks. Many times, a heart attack is the first sign of any problem, he adds.

Whether leptin concentrations in the blood will become a useful indicator of heart disease risk remains uncertain. Confirming or disproving an association between leptin and the disease will require further studies, Leyva says.