New research suggests that excess belly fat combined with high stress levels may boost the risk of developing type 2 diabetes in black women, a group disproportionately affected by the disease.

"Much attention has been given to the role of obesity in the development of type 2 diabetes, but stress may be as important in this at-risk population," said Dr. Anastasia Georgiades, of Duke University Medical Center, Durham, North Carolina.

She and colleagues determined the amount of fat in the abdomen of 62 healthy, nondiabetic African-American women and had them take an emotional stress test. As the women recalled stressful life events, the researchers measured their blood sugar and levels of epinephrine — the "fight or flight" hormone released in reaction to stress.

Women with a lot of belly fat and high epinephrine levels had high blood sugar during the stress test and while fasting. "Elevated fasting glucose (sugar) has been identified as a risk factor for the development of diabetes and cardiovascular disease," Dr. Richard Surwit, an investigator on the study, noted in an interview with Reuters Health.

In contrast, women with a low amount of belly fat and high stress and women with a lot of belly fat and low stress did not have high blood sugar.

It's no mystery why stress and obesity interact to raise blood sugar, Surwit said. "Epinephrine stimulates the breakdown of fat which leads to the production of free fatty acids. Free fatty acids compete with glucose as a fuel and basically raise blood sugar in that way," he explained.

"If you are overweight, then stress is going to interact with that extra weight and perhaps increase your blood sugar," he concluded. The findings were presented at the American Psychosomatic Society annual meeting.