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1762494 
Journal Article 
NEUROTOXIC EFFECTS OF FLUORIDE 
Spittle, B 
2011 
Yes 
Fluoride
ISSN: 0015-4725 
INT SOC FLUORIDE RESEARCH 
OCEAN VIEW 
44 
3 
117-124 
WOS:000295953600001 
This issue of Fluoride contains three new reports on
fluoride (F) and neurotoxicity. A study of neurotoxic effects of F in aluminum potroom workers in
Iran shows the importance of neurobehavioral testing for the early detection of cognitive
impairment in workers occupationally exposed to airborne F. Two studies, from Iran and India,
examined the IQ of children drinking high F water (2.38 and 2.45 mg F/L [ppm], respectively), but
only one of the two studies showed what was considered a statistically significant result.
Attention is thus drawn to the importance of examining confounding and effect-modifying factors.
For example, the reported protective effects of magnesium against F toxicity in certain drinking
waters, especially when they are soft, need to be considered. Whether there is a threshold at
which neurotoxicity from F begins to occur is examined by considering nine other studies showing
a significant association between lower IQ or neonatal neurobehavioral impairment and higher oral
F intake. If the accumulated evidence of human neurotoxicity from F is viewed dispassionately,
two conclusions can be drawn. Airborne F in industrial situations may pose a health risk to
workers and may be detected by neurobehavioral testing. The studies currently available on the
development of IQ all have their limitations, and although cases can be made, based on a pool of
eight reports and a paper by Xiang et al., respectively, for levels of F in drinking water of 0.1
and 0.185 mg F/L being safe for all children, other evidence, from Ding et al., suggests that
even a level as low as 0.081 mg F/L is not safe. Thus there is no threshold for F neurotoxicity
in drinking water, and the only assuredly safe level is zero. 
Airborne fluoride; Confounding factors; Effect-modifying factors; Fluoride threshold; IQ; Neurotoxicity; Psychomotor effects; Safety factor; Serum fluoride; Urinary fluoride; Water fluoride