Depressive symptoms appear to be predictive of the development of type 2 diabetes, according to a new study. In a study of more than 11,000 individuals, subjects in the highest quartile of depressive symptoms had a 63% increased risk of developing type 2 diabetes compared to those in the lowest quartile (relative hazard 1.63).

In a study published in the February issue of Diabetes Care, Dr. Sherita Hill Golden, of Johns Hopkins University School of Medicine, Baltimore, Maryland, and colleagues assessed data on depressive symptoms in a longitudinal, biracial cohort study of 11,615 initially nondiabetic adults who were followed for 6 years for the development of the disease.

 They recorded 721 cases of incident type 2 diabetes over 6 years of follow-up. This corresponded to an overall incidence rate of 12.4 per 1000 person-years.

The association between depressive symptoms and the risk of diabetes remained after adjustment for stress-associated lifestyle factors (relative hazard 1.28) and metabolic factor (relative hazard 1.38).

The authors suggest that there are at least four possible mechanisms by which depressive symptoms and diabetes could be linked. One is that "depressed individuals are less likely to be compliant with dietary and weight loss recommendations and are more likely to be physically inactive and nonadherent with medications." Others involve low socioeconomic status, antidepressants that might cause weight gain, and neurohormonal changes.

"Our study serves as a springboard for additional prospective studies using an established assessment tool to demonstrate an association between depression and diabetes with inclusion of neurohormonal measurements," Dr. Golden and colleagues write.

"Additional studies should determine whether amelioration of depressive symptoms might facilitate behavioral changes aimed at primary prevention of diabetes and whether HPA axis and sympathetic nervous system activation play an important role in the pathophysiology of weight gain and insulin resistance," they conclude.