Symptoms of depression as a risk factor for incident diabetes: findings from the National Health and Nutrition Examination Epidemiologic Follow-up Study, 1971-1992.

Symptoms of depression may predict incident diabetes independently or through established risk factors for diabetes. US men and women aged 25-74 years who were free of diabetes at baseline (n = 6,190) were followed from 1971 to 1992 (mean, 15.6 years; standard deviation, 6) for incident diabetes. Depressive symptoms were measured by using the General Well-Being Depression subscale and were categorized to compare persons with high (9%), intermediate (32%), and low (59%) numbers of symptoms. The incidence of diabetes was highest among participants reporting high numbers of depressive symptoms (7.3 per 1,000 person-years) and did not differ between persons reporting intermediate and low numbers of symptoms (3.4 and 3.6 per 1,000 person-years, respectively) (p < 0.01 for high vs. low). In the subset of participants with less than a high school education (a marker of low socioeconomic status), the risk of developing diabetes was three times higher (95% confidence interval: 2.0, 4.7) for persons reporting high versus low numbers of depressive symptoms. These results persisted following adjustment for established diabetes risk factors. Depressive symptoms had no impact on diabetes incidence among persons with at least a high school education. Results suggest an independent role for depressive symptoms in the development of diabetes in populations with low educational attainment.