Relationship between glycemic control and depression among American Indians in the Strong Heart Study

To examine the relationship between depression and glycemic control in the Strong Heart Study (SHS), a longitudinal study of cardiovascular disease in American Indians.

This cross-sectional analysis focused on the relationship between depression, diabetes and glycemic control among 2832 individuals aged > or =15 years. Depression was measured by the Center for Epidemiologic Studies of Depression Scale and diabetes by American Diabetes Association criteria. An ordered logit regression model was used to assess whether diabetes was related to level of depression (none, mild, moderate, severe). Multiple logistic regression was used to explore the relationship between A1c and severe depression in participants with diabetes.

Rates of depression were higher in men and women with diabetes when compared to those without diabetes, respectively (P<.05). For every 1-U increase in A1c, the odds of severe depression increased by 22% (OR 1.22, 95% CI: 1.05-1.42). Female sex (OR 2.97, 95% CI: 1.32-6.69) and body mass index (BMI) (OR 1.04, 95% CI: 1.00-1.08) also were significantly associated with increased risk for severe depression. Although BMI appears to be significantly associated with increased risk for severe depression, the magnitude of this effect was small.

Individuals with diabetes have higher rates of depression than those without diabetes, consistent with other populations. There is a positive relationship between severity of depression and A1c levels; men and women with severe depression have higher A1c levels than those with moderate-to-no depression.