A recent analysis (1) finding a negative relationship between fluoride exposure and adolescent IQ was prominently cited in decisions to end community water fluoridation (CWF) in parts of the United States. However, the quality and salience of that evidence have been questioned (2, 3). Most notably, the bulk of the evidence presented by Taylor et al. (1) concerned extremely high dosages of fluoride—far exceeding levels relevant to CWF policy discussions. None of their evidence came from population-representative samples; most failed to account for selection into treatment. None of the research was conducted using data collected in the United States.

this research was done to figure out the unknown