Economic, cognitive, and social paths of education to health-related behaviors: evidence from a population-based study in Japan

Background: There is substantial evidence on the association between lower education and unhealthy behaviors. However, the mechanism underlying this association remains unclear. This study aimed to examine whether income, health literacy, and social support mediate the association between education and health-related behaviors. Methods: A questionnaire survey was conducted in metropolitan areas in Japan from 2010 to 2011 among residents aged 25-50 years. Data from 3663 participants were used in this study. Health literacy was measured using the Communicative and Critical Health Literacy scale. Health-related behaviors were current smoking, poor dietary habits, hazardous drinking, and lack of exercise. Poisson regression analyses with robust variance estimators were conducted to examine the associations between education and these health-related behaviors. Multiple mediation analyses were conducted to estimate the magnitudes of the mediating effects of income, health literacy, and social support on these associations. Results: Less educated participants had higher risks of all unhealthy behaviors. Income mediated the associations of education with smoking (6.4%) and exercise (20.0%). Health literacy mediated the associations of education with dietary habits (15.4%) and exercise (16.1%). Social support mediated the associations of education with dietary habits (6.4%) and exercise (7.6%). The education-drinking association was mediated by income in the opposite direction (-10.0%). The proportions of the total effects mediated by income, health literacy, and social support were 9.8% for smoking, 24.0% for dietary habits, -3.0% for drinking, and 43.7% for exercise. Conclusions: These findings may provide clues for designing effective interventions to reduce educational inequalities in health-related behaviors.