The topic of fluoride developmental neurotoxicity has received great attention recently due to the publication of several high-profile studies and because of the questions these raise about the safety of water fluoridation, a long-established public health measure to reduce tooth decay. The recent studies have found associations between fluoride exposures at levels common in areas with artificial fluoridation and outcomes like reduced IQ and increased risk of ADHD in children. A 2019 draft systematic review by the National Toxicology Program (NTP) identified 149 human studies, including 18 it considered of relatively high quality. The large majority of these studies found adverse neurological effects. The NTP concluded fluoride was a presumed developmental neurotoxin but did not attempt any dose-response analyses. NTP’s conclusions about fluoride exposures due to artificially fluoridated water in the USA were equivocal. We give an overview of the human epidemiological evidence from the early studies done in the 1980s in China up to the most recent from Canada and the USA. We evaluated the strength of evidence at exposures relevant to artificial fluoridation. For the strongest studies with suitable data, we conducted dose-response analyses using Benchmark Dose methods with BMR = -1 IQ point. We also compare the quantity and quality of studies on fluoride developmental neurotoxicity to those for lead and other neurotoxins.
Conclusions. Multiple high quality studies, conducted in varied populations, consistently find strong associations between loss of IQ or other adverse developmental neurobehavioral outcomes and fluoride exposures commonly occurring from artificial fluoridation. Benchmark Dose analyses consistently find BMDL values well below mean exposure levels of pregnant women and children living in fluoridated areas. Thus, the evidence strongly suggests fluoridation poses an unprecedented neurotoxic risk to a large proportion of the children of the USA and other countries with fluoridation.
*Abstract in the Conference Abstract E-Posters at http://fluoridealert.org/wp-content/uploads/isee2020.abstract-e-posters.pdf
Chris Neurath, American Environmental Health Studies Project (AEHSP), Lexington, MA, United States
Paul Connett, American Environmental Health Studies Project (AEHSP), Binghamton, NY, United States
Michael Connett, Waters Kraus & Paul, El Segundo, CA
J. William Hirzy, American University Dept. of Chemistry, Washington, DC