Socioeconomic Status and Diabetes Prevalence in the Japanese: Insights From the JPHC-NEXT Study

To assess the association between socioeconomic status (SES) and diabetes prevalence among a Japanese population with a wide age range, stratified by gender.

Socioeconomic, behavioral, and diabetes-related data (diagnosis or medication use based on self-report) were collected from 112,492 participants aged 40 to 74 years using self-administered questionnaires in a population-based study across seven regions in Japan from January 1, 2011, through December 31, 2016. Logistic regression analyses, stratified by gender, were performed to estimate the association between each SES (income, education, and occupation) and diabetes prevalence after adjusting for demographic status, family history of diabetes, health-related behaviors, and body mass index. We also examined the heterogeneity of age (before or after retirement age - 60 years) with this association.

In women but not in men, lower household income and education were significantly associated with diabetes prevalence (lowest income quartiles vs highest income quartiles: 1.26 [Q1-Q3: 1.10-1.45]; junior high school vs college or higher: 1.20 [Q1-Q3: 1.13-1.28]). Unemployment was significantly associated with diabetes prevalence both in women and men (unemployed vs professionals or office workers: 1.18 [Q1-Q3: 1.10-1.27] in women, and 1.11 [Q1-Q3: 1.05-1.18] in men). The association of education and occupation with diabetes prevalence tended to be stronger at younger ages, although the heterogeneity by age was not significant.

Lower SES was associated with higher diabetes prevalence, especially in women, and the associations were stronger at younger ages in Japan. As in other countries, the strength of associations between SES and diabetes prevalence varied by gender in Japan.