The role of health behaviors in mediating the relationship between depressive symptoms and glycemic control in type 2 diabetes: a structural equation modeling approach

Objectives We investigated the longitudinal association between depressive symptoms and glycemic control (HbA1c) in adults with type 2 diabetes, and the extent to which that association was explained by health behaviors. Methods This study assessed data on 998 adults (aged 51 and above) with type 2 diabetes in the US nationally representative Health and Retirement Study and its diabetes-specific mail survey. Participants' depressive symptoms and baseline health behaviors (exercise, body weight control, and smoking status) were collected in 1998. Follow-up health behaviors and the glycemic control outcome were measured at a 2- and 5-year intervals, respectively. Results Nearly one in four of participants (23%) reported moderate or high levels of depressive symptoms at baseline (CES-D score >= 3). Adults with higher levels of depressive symptoms at baseline showed lower scores on baseline and follow-up health behaviors as well as higher HbA1c levels at a 5-year follow-up. Structural equation models (SEM) reveal that health behaviors accounted for 13% of the link between depressive symptoms and glycemic control. Conclusions The long-term relationship between depressive symptoms and glycemic control was supported in the present study. Health behaviors, including exercise, body weight control, and smoking status, explained a sizable amount of the association between depressive symptoms and glycemic control. More comprehensive diabetes selfcare behaviors should be examined with available data. Other competing explicators for the link, such as endocrinological process and antidepressant effects, also warrant further examination.