Income and wealth inequality is associated with young-onset type 2 diabetes.

Background: There are only a few studies on the influence of economic inequalities on young-onset type 2 diabetes (T2D).

Aim: To examine the impact of different family incomes on the development of young-onset T2D.

Methods: We identified 7505336 young adults aged 20-39 years from the 2008 Taiwan National Health Insurance Research Database. The young adults were divided into low-income, middle-income, and high-income groups. Cox proportional hazards models were used to determine the risks of young-onset T2D and all-cause mortality in low-income and middle-income groups compared with the high-income group.

Results: With a mean follow-up of 8.0 years, the incidence rates of young-onset T2D were 3.39, 3.10, and 2.88 per 1000 person-years in the low-income, middle-income, and high-income groups, respectively. Compared with the high-income group, the risk of young-onset T2D was significantly higher in the low-income [adjusted hazard ratio (aHR) (95%CI): 1.46 (1.44-1.48)] and middle-income [aHR (95%CI): 1.29 (1.27-1.31)] groups. All-cause mortality was also higher in the low-income [aHR (95%CI): 2.79 (2.70-2.88)] and middle-income [aHR (95%CI): 1.59 (1.53-1.65)] groups. Older age, male sex, obesity, smoking, alcohol-related disorders, hypertension, dyslipidemia, gout, and psychotic disorders were significantly associated with increased risks of both young-onset T2D and mortality.

Conclusion: This nationwide cohort study demonstrated that young people from low-income and middle-income groups had a higher risk of youth-onset T2D and mortality than those from the high-income group.