Unadjusted and adjusted prevalence of diagnosed depression in type 2 diabetes

To estimate the prevalence of diagnosed depression in a large population of individuals with type 2 diabetes, compared to a matched control group, and to estimate the extent of depression that is independently associated with diabetes.

We compared the prevalence of diagnosed depression in all 16180 full-year health maintenance organization members in 1999 who had been diagnosed with type 2 diabetes and in 16180 comparison members without diabetes matched for age and sex. We ascertained diagnoses from the Kaiser Permanente Northwest Region's electronic medical record. Using multiple logistic regression, we adjusted the prevalence estimates for the presence of cardiovascular disease, age, sex, and body weight.

Depression was more common in individuals with type 2 diabetes than among matched control subjects (17.9 vs. 11.2%; P < 0.001). Women in both groups were nearly twice as likely to be depressed as men; however, the relative difference in depression prevalence between subjects with and without diabetes was greater in men. In the multivariate model for women, body weight was a much stronger predictor of depression than diabetes status.

This study further documents the association between depression and diabetes, providing unadjusted population-based estimates in a large sample. Depression remained associated with diabetes after adjustment for several other possible causes. The association among diabetes, cardiovascular disease, depression, and obesity are multifaceted and differ for men and women.