Measures of depression and risk of type 2 diabetes: A systematic review and meta-analysis

Background: Depression is associated with an increased risk of type 2 diabetes. This study aimed to determine whether the association between depression and incident type 2 diabetes differs by measure of depression. Methods: Data sources included MEDLINE, EMBASE, PsycINFO, CINAHL, ProQuest Dissertations & Theses Global, Web of Science Emerging Sources Citation Index and Conference Proceedings Citation Index, Cochrane Library, the University of York Center for Reviews and Dissemination, abstracts from the PsychoSocial Aspects of Diabetes conference. Inclusion criteria: comparison of participants with and without depression, depression measured at age 18 or older, longitudinal follow-up with an outcome of type 2 diabetes, effect estimate adjusted for important confounders, full-text available in English or French, and study at overall low or moderate risk of bias. Two reviewers extracted data and assessed study quality. Results: Twenty-one studies reporting twenty-five effect estimates were included. Depressive symptom scales, clinical interviews, physician diagnoses, and use of antidepressants were all associated with an increased risk of incident type 2 diabetes. When all measures of depression were combined, the meta-analyzed risk ratio for type 2 diabetes was 1.18 (95% CI 1.12-1.24, I-2 =45.4%). Results did not provide conclusive evidence that the association between depression and incident diabetes differs by measure of depression. Limitations: Results showed heterogeneity and evidence of publication bias. Conclusions: Results suggest that various measures of depression may be used to identify individuals at higher risk of type 2 diabetes.