Impact of Fluoride on Associations between Free Sugars Intake and Dental Caries in US Children

Objective: Dental caries is the most prevalent chronic disease in US children, with the highest burden among Black and Hispanic youth. Sugars are a primary risk factor, but few studies have specifically measured intakes of free sugars and related this to dental caries or explored the extent to which water fluoride mitigates the cariogenicity of free sugars. Furthermore, the cariogenicity of certain free sugars sources, such as extruded fruit and vegetable products, is unclear. Methods: Using cross-sectional data on 4,906 children aged 2 to 19 y in the US National Health and Nutrition Examination Survey 2013–2016, we examined associations of free sugars intake with counts of decayed or filled primary tooth surfaces (dfs) and decayed, missing, or filled permanent surfaces (DMFS) in negative binomial regressions. Stratified models examined these associations in children with home water fluoride above or below the Centers for Disease Control and Prevention (CDC)–recommended level of 0.7 ppm. Results: Free sugars accounted for 16.4% of energy, primarily contributed by added sugars. In adjusted models, a doubling in the percentage of energy from free sugars was associated with 22% (95% confidence interval [CI], 1%–47%) greater dfs among children aged 2 to 8. A doubling in energy from added sugars was associated with 20% (95% CI, 1%–42%) greater dfs and 10% (95% CI, 2%–20%) greater DMFS in children aged 6 to 19 y. Beverages were the most important source of added sugars associated with increased caries. Other free sugars were not associated with dfs or DMFS. Associations between free sugars and caries were diminished among children with home water fluoride of 0.7 ppm or greater. Conclusions: Free sugars intake, especially in the form of added sugars and specifically in sweetened beverages, was associated with higher dental caries. Water fluoride exposures modify these associations, reducing caries risk in the primary dentition of children whose home water meets recommended fluoride levels. Knowledge Transfer Statement: Intake of free sugars, especially in the form of added sugars and specifically in beverages, was associated with higher dental caries in US children in this study. Water fluoride exposure at CDC-recommended levels protected against caries, especially in the primary dentition. These findings suggest that household water fluoridation at CDC-recommended levels protects against the cariogenic potential of free and added sugars during childhood.