Diabetes and suicide risk according to area-level deprivation: A nationwide cohort study in Japan

Although area-level deprivation affects the quality of diabetes management, it remains unclear whether the risk of diabetes-related suicide varies by area-level deprivation. We investigate whether the association between diabetes and suicide risk varies by area-level deprivation. We conducted a matched-pair cohort study using a nationwide health insurance database in Japan. Individuals with diabetes were matched 1:1 with those without diabetes by age, sex, and insurance status (i.e., insured person or their dependents). Area-level deprivation was assessed with a census-based Areal Deprivation Index (ADI), and we employed a Cox proportional hazards model to estimate the hazard ratio (HR) and 95 % confidence interval (CI) of suicide for individuals with diabetes by area-level deprivation level. Among 5,316,274 individuals (54.8 % men, mean age 52.9 years), we observed 760 suicides (incidence rate = 6.36/100,000 person-years). Individuals with diabetes experienced a higher risk of suicide than those without diabetes (HR = 1.33 [95 %CI 1.15–1.54]). The association between diabetes and suicide was stronger in less deprived areas than more deprived areas (the least deprived ADI quantile, HR = 1.89 [95 %CI 1.31–2.72]; the most deprived ADI quantile, HR = 1.15 [95 %CI 0.90–1.46]). Our findings suggest greater psychosocial challenges of diabetes diagnosis and management faced by individuals living in less deprived areas, or a possibility that diabetes diagnosis may serve as an equalizer of health disparities by improving healthcare access in more deprived areas.