Of 42 full-text publications reviewed, 13 met eligibility for depression predicting
onset of diabetes, representing 6,916 incident cases. Seven met criteria for diabetes predicting
onset of depression, representing 6,414 incident cases. The pooled relative risk (RR) for
incident depression associated with baseline diabetes was 1.15 (95% CI 1.02–1.30). The RR for
incident diabetes associated with baseline depression was 1.60 (1.37–1.88).