Socioeconomic disparities in adolescents' caries prevalence: Do oral health-related behaviors play intermediary roles?

Introduction: Policymakers and academics have explored the behavioral approach in their attempts to explain and address the socioeconomic disparities in adolescents' oral health. However, evidence regarding this issue is scarce in the Korean adolescent population. This study aimed to examine whether socioeconomic status is associated with dental caries and whether oral health-related behaviors (OHRBs) explain or moderate the hypothesized association in Korean adolescents. Methods: A secondary analysis was conducted using the Korea National Health and Nutrition Examination Survey data from 2016 to 2019. Adolescents (n = 1062) aged 13–18 years were included in the analysis. The association between income and untreated decayed permanent teeth (DT) was investigated, focusing on the intermediary roles of OHRBs, using hierarchical negative binomial regression models. Results: Higher income (incidence rate ratio [IRR] 0.70, P < 0.001), regular breakfast intake (IRR 0.64, P < 0.001), higher fruit and vegetable consumption (IRR 0.93, P < 0.001), preventive dental check-ups (IRR 0.84, P < 0.001), and frequent toothbrushing (IRR 0.73, P < 0.001) were associated with lower DT. The income-DT association remained significant and its magnitude was only slightly attenuated, after adjusting for OHRBs (IRR 0.74, P < 0.001). Significant interaction effects were found between income and each OHRB on DT (all with P < 0.001), and interaction patterns differed by behavior type: The income-DT association was stronger in the presence of unfavorable dietary-and favorable dental care-behaviors. Conclusion: The study findings suggested that adolescent oral health equity interventions should prioritize the structural approach and give more thorough consideration to the interactions between socioeconomic and behavioral factors.