Associations between Household Water Fluoridation Status and Plain Tap or Bottled Water Consumption

The benefits of community water fluoridation for preventing dental caries are attenuated if people do not consume tap water.

We examined associations between household water fluoride content and consuming plain tap or bottled water among US youth.

We used National Health and Nutrition Examination Survey data for 2013 to 2016 for 5,193 youth aged 2 to 19 y. Fluoride content in youth's household tap water samples was measured electrometrically with ion-specific electrodes and designated low (<0.6 mg/L) or about optimal (0.6 to 1.2 mg/L). Plain tap and bottled water consumption was obtained from one 24-h dietary recall. We used binomial regression models to estimate adjusted prevalence ratios (APRs) and 95% CIs for consuming plain tap water (including tap only or both tap and bottled) and consuming only bottled water as related to household water fluoride content (low or about optimal) and sociodemographic characteristics.

On a given day, 52.6% of youth consumed plain tap water (43.8% exclusively and 8.8% both tap and bottled) and 28%, only bottled water. Neither tap water (APR, 0.96; 95% CI, 0.84 to 1.10) nor only bottled water (APR, 1.03; 95% CI, 0.86 to 1.22) consumption was associated with household water fluoride content. Non-Hispanic Black youth and Hispanic youth were about 30% relatively less likely to consume tap water and 60% to 80% relatively more likely to consume only bottled water than non-Hispanic Whites. Low income, low parental education, and no past-year dental visit were associated with not consuming tap water.

Half of youth consumed plain tap water on a given day. Consuming plain tap water was not associated with community water fluoridation status. This study is the first to find that up to 50% of the population served by fluoridated water may not receive its full caries-preventive benefits due to not consuming plain tap water.

Half of US youth consumed plain tap water on a given day. Consuming plain tap water was not associated with community water fluoridation status. This finding suggests that up to 50% of the population served by fluoridated water systems may not receive its full caries-preventive benefits due to not consuming plain tap water. Our findings add support for the need to identify and address barriers to tap water consumption and promote health benefits of fluoridation.