Note: Only low risk-of-bias studies displayed in this figure. "F" represents fluoride.

For Yu et al. 2018, authors note an obvious decrease in the IQ score at water fluoride exposure levels between 3.40 mg/L and 3.90 mg/L and a similar adverse effect on IQ scores at urinary fluoride exposure levels from 1.60 mg/L to 2.50 mg/L, and so the changes in IQ score are indicated as significant; however, significance levels by change in IQ score were not reported.