Water Intake and Prevalence of Childhood Dental Caries

Objectives: High levels of water intake may decrease childhood caries. Risk may differ based on whether consumption is fluoridated tap water or bottled water. Bottle water is increasing as a total share of overall water intake but has suboptimal levels of fluoride. Our objective was to evaluate associations between amount and type of water intake and caries prevalence in children.
Methods: We conducted a community-based cross-sectional study in King County, Washington. We enrolled 452 low-income children in 1st-9th grade. We collected sociodemographic data, and frequency and amount of intake of beverages including fluoridated tap water, bottled water, sugar-sweetened beverages (SSBs), 100% fruit juice, and milk. We performed oral health examinations to estimate number of decayed, missing and filled teeth in primary dentition (dmft). We estimated descriptive statistics using means and percentages, and employed a multivariable model using Poisson regression and robust standard errors to estimate prevalence ratios (PR), adjusting for confounders (e.g. SSBs, juice, demographics).
Results: The mean age of participants was of 11.6 years, 27% were Hispanic, and 43% were black non-Hispanic (NH); 56% were food insecure and 64% were below 130% of the federal poverty level. In adjusted analyses, total intake of water (≥1-3, ≥3-5 and ≥5 versus <1 cup per day) was associated with a decreased caries (PRs 0.67-0.71, all p-values<0.01). Based on the same cutpoints, high intake of fluoridated tap water was associated with decreased caries (PRs 0.55-0.77, all p-values≤0.01); however bottled water intake, even at the highest levels was not associated with decreased caries (PRs 0.88-1.23, all p-values >0.05).
Conclusions: Total water intake decreases childhood caries prevalence and this association appears attributable to intake of fluoridated tap water. Bottled water intake is not associated with lower childhood caries prevalence. Efforts are needed to ensure fluoridated water is the primary source of water intake to prevent childhood caries.