FL: Fluoride and the Brain (2010)
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Assessment
What is the relation between exposure to high levels of fluoride in drinking water and IQ in children?
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Conclusion
All four primary studies consistently found a negative relationship between chronic exposure to high levels of fluoride (more than 3.15mg per L) and IQ in children when compared to children who live in areas with lower levels of fluoride in the drinking water (less than 1.0mg per L). The meta-analysis also reported the same relationship in 12 of the 16 studies examined. One of the four primary studies found a statistically significant increase in proportion of children with IQ of less than 80 when mean fluoride level in the water was 2.46±0.25mg per L.
Application to US populations is hampered by several limitations:
- Fluoride levels are often confounded with levels of other known neurotoxins (such as arsenic) in the studies, as fluoride was naturally occurring
- All populations studied were non-US settings (one Mexican and the rest Chinese); therefore, exposure levels and confounding factors may be quite different than in a US setting
- While none of the studies found an association between IQ and fluoride levels below 1.0mg per L, this research cannot be used to identify a safe upper limit.
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Grade: III
- Grade I means there is Good/Strong evidence supporting the statement;
- Grade II is Fair;
- Grade III is Limited/Weak;
- Grade IV is Expert Opinion Only;
- Grade V is Not Assignable.
- High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
- Moderate (B) means we are moderately confident in the effect estimate;
- Low (C) means our confidence in the effect estimate is limited;
- Very Low (D) means we have very little confidence in the effect estimate.
- Ungraded means a grade is not assignable.
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Evidence Summary: What is the effect of fluoride on the nervous system in children?
- Detail
- Quality Rating Summary
For a summary of the Quality Rating results, click here.
- Worksheets
- Coplan MJ, Patch SC, Masters RD, Bachman MS. Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Neurotoxicology. 2007 Sep; 28 (5): 1,032-1,042
- Lu, Y., Z.R. Sun, L.N. Wu, X. Wang, W. Lu, and S.S. Liu. 2000. Effect of high-fluoride water on intelligence in children. Fluoride 33 (2): 74-78.
- Masters, R.D., M.J. Coplan, B.T. Hone and J.E. Dykes. 2000. Association of silicofluoride treated water with elevated blood lead. Neurotoxicology 21(6): 1,091-1,100.
- Rocha-Amador D, Navarro ME, Carrizales L, Morales R, Calderón J. Decreased intelligence in children and exposure to fluoride and arsenic in drinking water. Cad Saude Publica. 2007; 23 Suppl 4: S579-S587.
- Takahashi, K. Fluoride-linked Down syndrome births and their estimated occurrence due to water fluoridation. Fluoride. 1998; 31(2): 61-73.
- Tang QQ, Du J, Ma HH, Jiang SJ, Zhou XJ. Fluoride and children's intelligence: a meta-analysis. Biol Trace Elem Res. 2008 Winter; 126 (1-3): 115-120. Epub 2008 Aug 10.
- Urbansky ET and Schock MR. Can fluoride affect lead (II) in potable water? Hexafluorosilicate and fluoride equilibria in aqueous solution. Int J Environ Studies. 2000; 57: 597-637.
- Wang SX, Wang ZH, Cheng XT, Li J, Sang ZP, Zhang XD, Han LL, Qiao XY, Wu ZM, Wang ZQ. Arsenic and fluoride exposure in drinking water: Children's IQ and growth in Shanyin county, Shanxi province, China. Environ Health Perspect. 2007; 115 (4): 643-647. Epub 2007 Jan 9.
- Whiting P, MacDonagh M, Kleijnen J. Association of Down's syndrome and water fluoride level: A systematic review of the evidence. BMC Public Health. 2001; 1-6.
- Xiang Q, Liang Y, Chen L, Wang C, Chen B, Chen X, Zhou M. Effect of fluoride in drinking water on children’s intelligence. Fluoride. 2003a; 36(2): 84-94.
- Detail
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Search Plan and Results: FL: Fluoride and the Nervous System 2009
What is the relation between silicofluoride exposure and blood lead levels in children?-
Conclusion
Water fluoridation with silicofluoride (but not sodium fluoride) may be associated with increased risk of elevated blood lead levels in children, especially those already at risk for lead exposure.
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Grade: III
- Grade I means there is Good/Strong evidence supporting the statement;
- Grade II is Fair;
- Grade III is Limited/Weak;
- Grade IV is Expert Opinion Only;
- Grade V is Not Assignable.
- High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
- Moderate (B) means we are moderately confident in the effect estimate;
- Low (C) means our confidence in the effect estimate is limited;
- Very Low (D) means we have very little confidence in the effect estimate.
- Ungraded means a grade is not assignable.
-
Evidence Summary: What is the effect of fluoride on the nervous system in children?
- Detail
- Quality Rating Summary
For a summary of the Quality Rating results, click here.
- Worksheets
- Coplan MJ, Patch SC, Masters RD, Bachman MS. Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Neurotoxicology. 2007 Sep; 28 (5): 1,032-1,042
- Lu, Y., Z.R. Sun, L.N. Wu, X. Wang, W. Lu, and S.S. Liu. 2000. Effect of high-fluoride water on intelligence in children. Fluoride 33 (2): 74-78.
- Masters, R.D., M.J. Coplan, B.T. Hone and J.E. Dykes. 2000. Association of silicofluoride treated water with elevated blood lead. Neurotoxicology 21(6): 1,091-1,100.
- Rocha-Amador D, Navarro ME, Carrizales L, Morales R, Calderón J. Decreased intelligence in children and exposure to fluoride and arsenic in drinking water. Cad Saude Publica. 2007; 23 Suppl 4: S579-S587.
- Takahashi, K. Fluoride-linked Down syndrome births and their estimated occurrence due to water fluoridation. Fluoride. 1998; 31(2): 61-73.
- Tang QQ, Du J, Ma HH, Jiang SJ, Zhou XJ. Fluoride and children's intelligence: a meta-analysis. Biol Trace Elem Res. 2008 Winter; 126 (1-3): 115-120. Epub 2008 Aug 10.
- Urbansky ET and Schock MR. Can fluoride affect lead (II) in potable water? Hexafluorosilicate and fluoride equilibria in aqueous solution. Int J Environ Studies. 2000; 57: 597-637.
- Wang SX, Wang ZH, Cheng XT, Li J, Sang ZP, Zhang XD, Han LL, Qiao XY, Wu ZM, Wang ZQ. Arsenic and fluoride exposure in drinking water: Children's IQ and growth in Shanyin county, Shanxi province, China. Environ Health Perspect. 2007; 115 (4): 643-647. Epub 2007 Jan 9.
- Whiting P, MacDonagh M, Kleijnen J. Association of Down's syndrome and water fluoride level: A systematic review of the evidence. BMC Public Health. 2001; 1-6.
- Xiang Q, Liang Y, Chen L, Wang C, Chen B, Chen X, Zhou M. Effect of fluoride in drinking water on children’s intelligence. Fluoride. 2003a; 36(2): 84-94.
- Detail
What is the relation between fluoride intake by mothers and Down Syndrome in children?-
Conclusion
There is no conclusive evidence of an association between fluoride intake and rate of Down Syndrome births.
-
Grade: III
- Grade I means there is Good/Strong evidence supporting the statement;
- Grade II is Fair;
- Grade III is Limited/Weak;
- Grade IV is Expert Opinion Only;
- Grade V is Not Assignable.
- High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
- Moderate (B) means we are moderately confident in the effect estimate;
- Low (C) means our confidence in the effect estimate is limited;
- Very Low (D) means we have very little confidence in the effect estimate.
- Ungraded means a grade is not assignable.
-
Evidence Summary: What is the effect of fluoride on the nervous system in children?
- Detail
- Quality Rating Summary
For a summary of the Quality Rating results, click here.
- Worksheets
- Coplan MJ, Patch SC, Masters RD, Bachman MS. Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Neurotoxicology. 2007 Sep; 28 (5): 1,032-1,042
- Lu, Y., Z.R. Sun, L.N. Wu, X. Wang, W. Lu, and S.S. Liu. 2000. Effect of high-fluoride water on intelligence in children. Fluoride 33 (2): 74-78.
- Masters, R.D., M.J. Coplan, B.T. Hone and J.E. Dykes. 2000. Association of silicofluoride treated water with elevated blood lead. Neurotoxicology 21(6): 1,091-1,100.
- Rocha-Amador D, Navarro ME, Carrizales L, Morales R, Calderón J. Decreased intelligence in children and exposure to fluoride and arsenic in drinking water. Cad Saude Publica. 2007; 23 Suppl 4: S579-S587.
- Takahashi, K. Fluoride-linked Down syndrome births and their estimated occurrence due to water fluoridation. Fluoride. 1998; 31(2): 61-73.
- Tang QQ, Du J, Ma HH, Jiang SJ, Zhou XJ. Fluoride and children's intelligence: a meta-analysis. Biol Trace Elem Res. 2008 Winter; 126 (1-3): 115-120. Epub 2008 Aug 10.
- Urbansky ET and Schock MR. Can fluoride affect lead (II) in potable water? Hexafluorosilicate and fluoride equilibria in aqueous solution. Int J Environ Studies. 2000; 57: 597-637.
- Wang SX, Wang ZH, Cheng XT, Li J, Sang ZP, Zhang XD, Han LL, Qiao XY, Wu ZM, Wang ZQ. Arsenic and fluoride exposure in drinking water: Children's IQ and growth in Shanyin county, Shanxi province, China. Environ Health Perspect. 2007; 115 (4): 643-647. Epub 2007 Jan 9.
- Whiting P, MacDonagh M, Kleijnen J. Association of Down's syndrome and water fluoride level: A systematic review of the evidence. BMC Public Health. 2001; 1-6.
- Xiang Q, Liang Y, Chen L, Wang C, Chen B, Chen X, Zhou M. Effect of fluoride in drinking water on children’s intelligence. Fluoride. 2003a; 36(2): 84-94.
- Detail
-
Conclusion