Trends in self-reported current diabetes care use, socioeconomic inequalities, and associated factors in Japan: evidence from the Comprehensive Survey of Living Conditions (1986–2022)

INTRODUCTION: Long-term trends in diabetes care use and socioeconomic inequalities are not well described in Japan. RESEARCH DESIGN AND METHODS: We analyzed nationally representative data from the Comprehensive Survey of Living Conditions (1986-2022). Diabetes care use was defined as self-reported current medical facility attendance for diabetes. Age-standardized prevalence was calculated as the proportion of adults currently receiving outpatient diabetes care; undiagnosed cases and diagnosed individuals not currently in treatment were therefore not captured. In the 2022 survey, a survey-weighted Poisson regression model was used to estimate prevalence ratios (PRs) of factors associated with current diabetes care use, including educational level and occupational class. RESULTS: Age-standardized self-reported current diabetes care use increased from 1986 to 2022, rising from 2.2% to 8.3% in men and from 1.7% to 4.4% in women, with a significant widening of the sex inequalities over the study period. Educational differences were evident, particularly among working-age adults. In 2022, compared with the high-education group, PRs were 1.17 (95% CI 1.13 to 1.22) for the middle-education group and 1.22 (95% CI 1.13 to 1.32) for the low-education group for both sexes. Occupational differences were more modest. Compared with upper non-manual workers, lower non-manual workers had a lower PR=0.92 (95% CI 0.86 to 0.98), while non-employed individuals had a higher PR=1.10 (95% CI 1.01 to 1.21); manual workers, self-employed individuals, and farmers did not differ significantly from the reference group. Older age, men, hypertension, depression, and current smoking were also associated with higher current diabetes care use. CONCLUSIONS: Self-reported diabetes care use increased from 1986 to 2022 in Japan, with lower educational level associated with higher current diabetes care use, particularly among working-age adults. These findings help inform continued monitoring of socioeconomic inequalities in diabetes care.