Does public transportation reduce inequalities in access to dental care among older adults? Japan Gerontological Evaluation Study

Objectives: Income inequalities in access to dental care have been reported worldwide. While geographical accessibility may affect inequalities, no study has examined whether the use of public transportation reduces income inequalities in access to dental care. Therefore, we examined whether the use of public transportation is associated with reduced income inequalities in access to dental care. Methods: This cross-sectional study used data from the Japan Gerontological Evaluation Study conducted in 2016. Self-reported questionnaires were distributed to 34 567 community-dwelling independent older adults aged 65 years or over from 39 municipalities. The dependent variable was dental attendance for any treatment. The independent variables were daily public transportation use and household equivalent income. The covariates were age, years of education, marital status, self-rated health, number of teeth, car use, having bus stops or railway stations nearby for individual level and density of dental clinics for community level. After multiple imputation, a two-level linear regression analysis was performed and stratified by sex. Results: The mean age of the 19 664 participants (response rate: 69.9%) was 73.8 years (standard deviation = 6.1). Among the participants with dental attendance for treatment in the past six months, daily public transportation users represented 45.5% of men and 56.1% of women. These users had higher levels of dental attendance for treatment (β =.109, 95% confidence interval (CI) = 0.051-0.166 for men, β =.094, 95% CI = 0.039-0.149 for women) than nondaily users. Household equivalent income was positively associated with higher dental attendance for treatment (β =.046, 95% CI = 0.029-0.062 for men, β =.029, 95% CI = 0.013-0.045 for women). Income inequalities in access to dental care were smaller among the daily public transportation users than in nondaily users, and a statistically significant interaction was observed only in men (P-value interactions =.025 for men,.188 for women). Conclusion: Income inequalities in access to dental care were smaller among older daily users of public transportation than in nondaily users. These results suggest that providing environment in which people can conveniently use public transportation is needed for reducing income inequalities in access to dental care, especially for men.