Depression, Diabetes, and Social Support

Over the past two decades, evidence has steadily accumulated to support a bidirectional relationship between depression and type 2 diabetes. The stress-buffering model suggests that social support moderates or “buffers” stress so that the deleterious effects of stress impact physical health less. The overall goals of the present study were to explore the nature of the relationship between depression and diabetes and to determine whether social support moderates this relationship. Secondary data analyses were conducted using three large datasets: the Diabetes Prevention Program and Diabetes Prevention Program Outcomes Study (DPP/DPPOS) from the National Institute of Diabetes and Digestive and Kidney Diseases; the 2007-2008 National Health and Nutrition Examination Survey (NHANES) from the Centers for Disease Control and Prevention’s National Center for Health Statistics; and the Arthritis, Coping, and Emotion Study (ACES), which is local to Johnston County, North Carolina. Hierarchical logistic regression models were used for NHANES and ACES, and Cox proportional hazards regression was used for DPP. For the DPP study, hazard of diabetes diagnosis became 22% higher for every ten-point increase in Beck Depression Inventory score [HR = 1.22]. For the NHANES study, odds of diabetes increased by 49% for every ten-point increase the nine-item Patient Health Questionnaire score [OR: 1.49]. For the ACES study, odds of diabetes associated with a ten-point increase in Center for Epidemiologic Studies – Depression inventory score increased by 11% [OR: 1.11]. Having ever had depressive symptoms increased odds of having diabetes by 31 to 57%, and having had depressive symptoms in the previous 12 months was associated with a 63 to 71% increase in odds of diabetes, controlling for three different indices of social support. No significant moderation effect was found for social support in any of the models, and all models controlled for demographic, biological, and behavioral covariates. This study contributes to the growing body of literature on the importance of mental health in physical health outcomes and suggests that social support does not buffer the deleterious impacts of depression on physical health.