Socioeconomic status and type 2 diabetes complications among young adult patients in Japan.

Objective: To assess the relationship between socioeconomic status (SES) and complications of type 2 diabetes among young adults in Japan.

Design: A cross-sectional study.

Setting: Outpatient wards of 96 member hospitals and clinics of the Japan Federation of Democratic Medical Institutions.

Participants: A total of 782 outpatients with type 2 diabetes (525 males, 257 females), aged 20-40 years as of March 31, 2012. After excluding 110 participants whose retinopathy diagnosis was in question, 672 participants were analyzed.

Measurements: We examined the relations between SES (educational level, income, type of public healthcare insurance, and employment status) and diabetes complications (retinopathy and nephropathy) using a multivariate logistic regression analysis.

Results: The prevalence of type 2 diabetic retinopathy was 23.2%, while that of nephropathy was 8.9%. The odds of having retinopathy were higher among junior high school graduates (OR 1.91, 95% CI 1.09-3.34), patients receiving public assistance (OR 2.19, 95% CI 1.20-3.95), and patients with irregular (OR 1.72, 95% CI 1.03-2.86) or no employment (OR 2.23, 95% CI 1.36-3.68), compared to those with a higher SES, even after covariate adjustment (e.g., age, gender, body mass index). Similarly, the odds of having nephropathy were higher among patients with middle (OR 3.61, 95% CI 1.69-8.27) or low income levels (OR 2.53, 95% CI 1.11-6.07), even after covariate adjustment.

Conclusions: Low SES was associated with a greater likelihood of type 2 diabetes complications in young adults. These findings suggest the necessity of health policies that mitigate socioeconomic disparity and thereby reduce the prevalence of diabetic complications.