Singing the blues

From San Antonio, Texas, at the 60th annual meeting of the American Diabetes Association

Although the idea’s controversial, a few diabetes researchers are suggesting that depression, which is common among people with chronic diseases including diabetes, may sometimes cause the disease.

In a managed-care group in Portland, the 1,680 people who developed diabetes in 1998 were slightly more likely to have histories of depression than were 1,680 people who didn’t develop diabetes, says Gregory A. Nichols of the Kaiser Permanente Center for Health Research in Portland. The researchers matched the groups by age and approximate date of enrollment in the plan.

About 350 people with diabetes had at least one episode of depression during the 11 years before their diagnosis with diabetes, he says, compared with about 300 of the participants without diabetes. “Our data suggest that depression frequently preceded diabetes,” Nichols says. “This is not an overwhelming effect, but it is statistically significant.”

His results support the idea that depression might cause diabetes, he says. Some research has suggested that depression alters the body’s hormone balance and makes a person less sensitive to the effects of insulin.

Depression may also prompt behavior that predisposes people to both diabetes and heart disease, says Nichols. For instance, he says, depressed people are more likely to be obese, less likely to be physically active, and less likely to take prescribed medications than are people who aren’t depressed.