G-Computation Quantifying Caries Reduction by World Health Organization Sugar Limits in Children

The World Health Organization (WHO) recommends reducing free sugar intake (FSI) to below 10%, and ideally below 5%, of the estimated energy requirement (EER) to prevent noncommunicable diseases, including dental caries. Little progress has been made in lowering FSI to reduce early childhood caries (ECC) over the past few decades. Although sugar's impact on health is well established, no studies have quantified the extent to which reducing FSI to these thresholds would reduce decayed, missing, and filled surfaces (dmfs) scores. Data from 2,182 Australian children in the SMILE birth cohort were analyzed using G-computation analysis to estimate counterfactual dmfs if FSI at age 2 y had been reduced below 10% or 5% of the EER. A dose-response analysis using restricted cubic splines was also conducted to empirically assess thresholds by modeling dmfs at age 5 y as a function of continuous FSI. The G-computation results indicate that, in the general preschool population, reducing FSI to less than 10% or 5% of the EER would result in an absolute reduction (AR) in dmfs of 1.3 and 1.5, respectively, corresponding to attributable fractions among the exposed (AFE) of 84% and 97%. Among high-risk children, the estimation impact is even greater, with ARs in dmfs of 4.4 to 4.5 and AFEs ranging from 75% to 99%. The dose-response analysis identified an empirical threshold of approximately 6.25 g/d, equivalent to 2.5% of the EER, where dmfs began to increase most steeply, which is lower than the WHO cutoffs. These findings underscore the importance of reducing FSI to below 10% of the EER for all children and suggest a target below 5% for high-risk groups. The results offer evidence to support clinical guidance and population-level interventions to lower FSI in early childhood. Future research should test these findings in diverse sociocultural settings, including children and adults in low- and middle-income countries, to strengthen the evidence for global dietary sugar-reduction policies.