Increased risk of incident mental disorders in adults with new-onset type 1 diabetes diagnosed after the age of 19: A nationwide cohort study

Aim: This population-based study aimed to investigate the risk of mental disorders in adults with new-onset type 1 diabetes mellitus compared to the general population without diabetes. Methods: We selected 10,391 adults with new-onset type 1 diabetes and 51,995 adults in the general population without diabetes with a median follow-up of 7.94 years using the National Health Insurance Database in South Korea between January 2009 and December 2020. The adjusted hazard ratios (aHRs) were estimated for the occurrence of mental disorders. Results: The incidence of mental disorders was more than twice as high in patients with new-onset type 1 diabetes (66 per 1000 person-years) than in those without diabetes (29 per 1000 person-years). The aHR [95 % confidence interval] comparing adults with new-onset type 1 diabetes with those without diabetes were 2.20 [2.12.2.29] for mental disorders, 3.16 [2.99.3.35], for depression, 2.55 [2.32.2.80] for mood disorders, 1.89 [1.80.1.97] for anxiety and stress related disorders, 2.50 [1.48.4.22] for eating disorders, 2.62 [1.45.4.73] for personality and behavior disorders and 4.39 [3.55.5.43] for alcohol and drug misuse disorders. When new-onset type 1 diabetes occurred at the age of 41 to 50, the aHR of developing mental illness was 2.43 [2.19.2.70], compared to those without diabetes. Conclusions: In this nationwide prospective study, new-onset type 1 diabetes in adulthood was significantly associated with a higher risk of mental disorders than in the general population without diabetes.