Estimation of Total Daily Fluoride Intake in Europe and Correlation to Equivalent Doses in Epidemiological Studies.

European populations are chronically exposed to fluoride, as fluoride is supplemented for caries prophylaxis and is furthermore present in some food sources. As there is evidence that fluoride exposure at drinking water concentrations above 1.5 mg/L is associated with lower IQ in children, total daily intake in Europe might be close to or above this exposure level. Concerning health effects in Europe, epidemiological data are limited. Therefore, it would be beneficial to consider existing studies from non-EU countries to transfer observed effects to the exposure situation in Europe. Additionally, animal data could also deliver supporting information, if equivalent doses could be calculated. In this work, a methodology was developed to determine daily fluoride intake and excretion in Europe and align it to concentrations reported in animal and epidemiological studies. With this, a total daily intake of 2.05-mg fluoride for 3-year-old children and 3.8-mg fluoride for adults was estimated. For 3-year-olds, this value exceeds the current recommendations of fluoride intake by EFSA and even the tolerable upper intake level. The daily urinary fluoride excretion was calculated to be 0.72 mg/day, and for adults, it was 2.05 mg/day. For in vivo studies, rat exposure to fluoride drinking water concentrations of 12.5 ppm was considered to be equivalent to the daily fluoride intake in Europe. With the presented approach, equivalent doses can be applied to select international epidemiological as well as in vivo studies reflecting the fluoride exposure situation in European countries to extrapolate potential health effects.