Key Mediators Reducing Socioeconomic Inequality in Early Childhood Caries

Socioeconomic status (SES) has a significant effect on the burden of early childhood caries (ECC), yet addressing SES disparities remains challenging. This study aimed to identify and quantify the most impactful mediator linking SES effect to the occurrence of ECC using advanced causal mediation analysis, to inform targeted interventions that reduce SES-related disparities in ECC.

Data were drawn from the Study of Mothers' and Infants' Life Events, a cohort of 2,182 mother-child dyads recruited from Adelaide's 3 largest public hospitals (2013-2014). Baseline questionnaires captured family SES, while ECC clinical indicators were assessed at age 5 y. Three mediation pathways linking SES and ECC were examined including dietary intake represented by free sugar intake (FSI); oral hygiene practices, including toothbrushing habits and plaque presence; and dental visiting patterns. Mediation effects were quantified as natural indirect effects (NIE) using causal mediation analysis based on the counterfactual framework, with validation via 5-fold cross-validation to ensure robustness.

FSI was the only pathway with a significant mediation effect. Each 1-standard-deviation increase or decrease in SES was associated with a corresponding 6% reduction or increase in ECC risk at age 5 y through the mediating effect of FSI at age 2 y. The NIE of FSI accounted for 52% of SES's total effect on ECC. In contrast, oral hygiene and dental visiting patterns showed no significant mediation effects.

Reducing early childhood FSI could mitigate half of SES-related disparities in ECC. Targeted interventions focusing on FSI reduction hold promise for lowering ECC risk, with future research needed to evaluate their effectiveness.Knowledge Transfer Statement:Clinicians and policymakers should prioritize nutrition education and sugar reduction initiatives as key components of early prevention in pediatric dentistry, especially for low-SES populations. Incorporating FSI screening into routine visits enables medical and dental practitioners to educate caregivers on the impact of free sugars on dental health.