Aug 1, 2012 by MARCO TORRES
Study Confirms Fluoridated Water Affects IQ and Neurobehavioral Development in Children
Although fluoride has been proven to cause neurotoxicity in animal models, very little published research has elaborated on acute fluoride poisoning and neurotoxicity in adults and children. A report in a peer-reviewed open access journal published by the National Institute of Environmental Health Sciences performed a systematic review and meta-analysis of published studies to investigate the effects of increased fluoride exposure and delayed neurobehavioral development.
One year ago, a study published in Neurologia showed "the prolonged ingestion of fluoride may cause significant damage to health and particularly to the nervous system." That was the conclusion by a review of studies by researchers Valdez-Jimenez, et al.
Now evidence has emerged confirming toxicity to the brain. Researchers Anna L. Choi, Guifan Sun, Ying Zhang and Philippe Grandjean researched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNET databases through 2011 for eligible studies.
In total, they identified 27 eligible epidemiological studies with high and reference exposures, endpoints of IQ scores or related cognitive function measures with means and variances for the two exposure groups. They estimated the standardized mean difference (SMD) between exposed and reference groups across all studies using random effects models.
The researchers conducted sensitivity analyses restricted to studies using the same outcome assessment and having drinking water fluoride as the only exposure.
The standardized weighted mean difference in IQ score between exposed and reference populations showed that populations in high fluoride areas had significantly lower IQ scores than those who lived in low fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although the substantial heterogeneity did not appear to decrease.
The results found in human populations support previous research on animal models. The adverse effects of high fluoride exposure on children’s neurodevelopment is a reality. The authors noted that future research should include detailed individual-level information on prenatal exposure and neurobehavioral performance.
"Fluoride, the most consumed drug in the USA, is deliberately added to 2/3 of public water supplies theoretically to reduce tooth decay, but with no scientifically-valid evidence proving safety or effectiveness," says lawyer Paul Beeber, President, New York State Coalition Opposed to Fluoridation.
"Some recent studies suggest that over-consumption of fluoride can raise the risks of disorders affecting teeth, bones, the brain and the thyroid gland," reports Scientific American editors (January 2008). "Scientific attitudes toward fluoridation may be starting to shift," writes author Dan Fagin.
Marco Torres is a research specialist, writer and consumer advocate for healthy lifestyles. He holds degrees in Public Health and Environmental Science and is a professional speaker on topics such as disease prevention, environmental toxins and health policy.