Mental disorders as risk factors for type 2 diabetes: an umbrella review with policy implications

Background

Improving our understanding of modifiable risk factors for type 2 diabetes (T2D) is essential for strengthening primary prevention. Treatable mental disorders have increasingly attracted attention in this area, highlighting a shift from a single-disease approach to a multimorbidity perspective. We conducted an umbrella review to evaluate the scope, consistency, and strength of the available evidence.

Methods

Meta-analyses, cohort studies (not included in meta-analyses) and Mendelian randomization studies (MRS) published through 03/2026 were identified via the main biomedical databases, supplemented by manual searches. Eligibility criteria included: adults free of diabetes at baseline, incident T2D assessed after baseline measurement of anxiety, depressive or sleep disorders.

Results

For anxiety disorders, risk estimates from meta-analyses (N = 2) ranged from 1.19 to 1.34; from MRS (N = 2) the range was 1.05 - 1.15; from cohort studies (N = 11) the range was 0.73 - 2.30. For depressive disorders, risk estimates from meta-analyses (N = 9) ranged from 1.08 to 1.67; from MRS (N = 3) from 0.96 to 1.33; from cohort studies (N = 22) from 0.50 to 3.93. For sleep disorders/insomnia, risk estimates from meta-analyses (N = 3) ranged from 1.38 to 2.29; from MRS (N = 9) the range was 0.15 - 1.89; from cohort studies (N = 17) the range was 0.96 - 2.64. This literature is characterized by methodological heterogeneity regarding study populations, measurement tools, follow-up duration, and covariate adjustment.

Conclusions

Multiple meta-analyses provide convincing evidence for mental disorders as independent risk factors for incident T2D. Depressive disorders have been the most extensively studied mental disorders in this domain. The findings support greater integration of mental health into T2D prevention strategies and highlight the need for adopting a multimorbidity perspective in research, clinical settings, and policy.

Key messages

• Multimorbidity requires a paradigm shift away from a single-disease model in order to develop better primary and secondary prevention.

• Mental-physical multimorbidity impacts individuals of all ages and has implications for healthcare, research and policy.