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Table 1 Characteristics of 14 cross-sectional studies of fluoride exposure and children’s cognitive and developmental outcomes published after 2012

From: Developmental fluoride neurotoxicity: an updated review

ReferenceStudy location, yearNo. in high-exposure groupNo. in reference groupAge range (or mean), yearsFluoride exposureOutcome measureResults
AssessmentMean or range (mg/L)
[96]China, 2014123428–12Urine3.03 (urine, short-term); 2.33 (urine, long-term); 1.34 (urine, ref)RSPMaFluoride exposure was negatively associated with children’s IQ
[97]China, 201526 (moderate/severe dental fluorosis)8 (normal/questionable dental fluorosis)6–8Drinking water, urine2.66 (water, moderate/severe); 1.0 (water, normal/questionable); 2.44 (urine, moderate/severe); 0.45 (urine, normal/questionable)WRAMLb; WISC-IVcModerate and severe fluorosis were significantly associated with deficits in digit span scores.
[98]India, 20152152146–12Drinking water2.41 (water, high); 0.19 (water, ref)RCPMdIQs of highly exposed children were significantly lower than those with low-level exposure
[99]China, 201584967–13Drinking water, urine1.40 (water, high); 0.63 (water, ref); 2.40 (urine, high); 1.10 (urine, ref)CRT-RCeFluoride exposure was negatively associated with children’s IQ
[100]India, 201623 (severe dental fluorosis)4 (normal dental fluorosis)6–18Groundwater and urine2.11 (water); 0.45–17.00 (range, urine)CRT-RCeIQ was negatively correlated with degree of dental fluorosis
[101]China, 201768503–12 monthsCoal burning vs. controlMothers in exposed group had dental fluorosisMDI & PDI (CDCC)fMDI & PDI in exposed group were significantly lower than those in the control group
[102]China, 20171671208–12Coal burning vs. controlDental fluorosis index 53.9% in exposed groupRSPMaIQ was lower in children with high fluoride exposure (not significant)
[103]China, 20182211008–12Drinking water1.2 (water, high); 0.25 and 0.78 (water, controls)CRT-RCeIQ was lower in children from endemic areas and in those with dental fluorosis
[104]Sudan, 2018775 (total)N/a6–14Drinking water0.01–2.07 (water)School performance based on method adopted by MoEInverse relationship between fluoride in drinking water and average school performance
[105]China, 20181341348–12Dental fluorosisN/aCRT-RCeIQ was lower in children from endemic areas
[106]Egypt, 20181868144.6–11Drinking water0.92–3.75 (water)DAPgDecreased scores in children from areas with elevated fluoride in drinking water
[107]China, 2018125016367–13Drinking water and urine2.00 + 0.75 (water, high); 1.37 + 1.08 (urine, high); 0.50 + 0.27 (water, ref); 0.41 + 0.49 (urine, ref)CRT-RC2eIQ was lower in children at higher fluoride in water and urine and at greater severity of dental fluorosis
[108]China, 201925278–12Drinking waterN/aCRT-RC2eIQ was lower at elevated fluoride exposure
[109]China, 2020571 (total)N/a7–13Drinking water, urine1.39 + 1.01 (water); 1.28 + 1.30 (urine)CRT-RC2eLow to moderate fluoride exposure is associated with alterations in thyroid function and lower IQ
  1. aRaven’s Standardized Progressive Matrices; bWide Range Assessment of Memory and Learning; cWechsler Intelligence Scale for Children-Revised; dRaven’s Colored Progressive Matrices; eCombined Raven’s Test-The Rural in China; fmental development index & psychomotor development index (assessed using the Standardized Scale for the Intelligence of Children formulated by the Children Development Center of China; gDAP, Draw-A-Person