Bidirectional longitudinal study of type 2 diabetes and depression symptoms in black and white church going adults

Background: There is a need to longitudinally examine depression and DM2 relationship in a population that values positive health behaviors. The aim of this study was to prospectively investigate the bidirectional relationship between depression and DM2. Methods: A cohort sample of 4,746 Black (28.4%) and White (71.6%) Seventh-day Adventist adults who participated in the Biopsychosocial Religion and Health Study (BRHS) completed a short form of the Center for Epidemiologic Studies Depression Scale (CES-D) 11 along with self-report of lifetime physician diagnosis of type 2 diabetes (DM2) and treatment of DM2 and/or depression in the last 12 months in 2006-7 and 2010-11. Hierarchical logistic regression analyses were completed to predict risk for future disease while controlling for demographic and health related variables. Results: While there were no direct effects of depression on later DM2, there was an indirect effect mediated by BMI (effect = 0.13; 95% CIs [0.08, 0.20]) even after controlling for demographic variables as covariates using Hayes' PROCESS macro mediation analysis. Similarly, there was also only an indirect effect of DM2 on later depression mediated by BMI (effect = 0.13; 95% CIs [0.05, 0.22]) after controlling for demographic variables. Conclusions: The results highlight BMI as a risk factor for both DM2 and depression. The negative consequences of having higher BMI in conjunction at baseline with another disease can increase the risk for other chronic disease even in a span of 2.04 - 5.74 years, the length of study interval.