Prediabetes, depressive and anxiety symptoms, and risk of type 2 diabetes: A community-based cohort study

Objective: To examine the potential synergistic associations between prediabetes, depressive and anxiety symptoms, and the risk of incident type 2 diabetes. Methods: Data were from the Emotional Well-Being, Metabolic Factors and Health Status (EMHS) study and included 2486 adults between 40 and 69 years without diabetes at baseline. Hemoglobin Alc levels and measures of depressive and anxiety symptoms were collected at baseline and mutually exclusive groups were formed based on the presence/absence of prediabetes and high/low depressive and anxiety symptoms. A follow-up telephone interview conducted approximately 4.6 years later inquired about new diabetes diagnoses. Results: 86 participants developed diabetes during the follow-up period. After accounting for sociodemographic, lifestyle, and metabolic characteristics, participants with prediabetes and elevated depressive symptoms had an increased risk of developing diabetes compared to those without prediabetes and with low depressive symptoms (OR = 10.65, 95% CI = 4.60, 24.66). The joint effect of prediabetes and depressive symptoms on diabetes risk was synergistic (Synergy Index = 2.57, 95% CI = 1.02, 6.49). Similar results were found for participants with prediabetes and high symptoms of anxiety (OR = 8.95, 95% CI = 3.54, 22.63), however the joint effect of prediabetes and anxiety symptoms did not significantly exceed additive risk after adjusting for covariates (Synergy Index = 239, 95% CI = 0.83, 6.87). Conclusion: The combination of prediabetes and depressive or anxiety symptoms was associated with an increased risk of developing diabetes. This study underscores the importance of mental health in the progression from prediabetes to type 2 diabetes. (C) 2016 Elsevier Inc. All rights reserved.