Type 2 Diabetes and Its Association With Psychiatric Disorders in Young Adults in South Korea

Abstract

Importance: Because type 2 diabetes (T2D) has become increasingly prevalent among young adults, the study of the association of T2D with psychiatric disorders in young adults is important for early detection and timely intervention. Objective: To determine whether a diagnosis of a psychiatric disorder is associated with increased risk of developing T2D in young adults. Design, Setting, and Participants: This large-scale prospective cohort study used data collected by the South Korean National Health Insurance Service between 2009 and 2012, representing 97% of the South Korean population. Young adults aged 20 to 39 years with and without diagnoses of psychiatric disorders were included in the study. Young adults with missing data and those with a history of T2D were excluded from the study. The cohort was followed up to monitor development of T2D until December 2018. Data were analyzed from March 2021 to February 2022. Exposure: Diagnosis of 1 of 5 psychiatric disorders, including schizophrenia, bipolar disorder, depressive disorder, anxiety disorder, and sleep disorder. Main Outcomes and Measures: The primary outcome was newly diagnosed T2D during a follow-up period of 7.59 years. The incidence rate of T2D was calculated as the number of new cases per 1000 person-years during the follow-up period. The Cox proportional hazards regression model was used to estimate the hazard ratios (HRs) and 95% CIs for T2D incidence. Exploratory analyses were performed for subgroups stratified by age and sex. Results: In total, 6457991 young adults (mean [SD] age, 30.74 [4.98] years; 3821858 men [59.18%]) were followed up, including 658430 individuals with psychiatric disorders. The cumulative incidence of T2D differed significantly between individuals with and without psychiatric disorders (log-rank test, P