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when they looked at low fluoride versus high fluoride exposure (up to 11.5 ppm or mg/L in drinking <br /> water) in children from these various studies (ranging age 4-14) they detected a very small reduction in <br /> IQ (0.5 points). The authors state that many of the reviewed studies had flaws, often rather serious, <br /> including that the actual exposure of the individual children to fluoride was never directly measured, <br /> that several of the studies provided evidence of co-exposure to arsenic (a neurotoxin) or did not <br /> apparently assess arsenic exposure, that iodine levels are high in some studies and low in others, which <br /> could impact fluoride metabolism, etc. Furthermore, the reason that the studies used in this compilation <br /> work are "not widely disseminated" is because they are often published in Chinese and/or Chinese <br /> regional journals not readily available to most scientists and this makes it difficult for an independent <br /> scientific reviewer to assess their quality (rigor of their methods, results, etc.). Overall the conclusions of <br /> this review are undercut by the unknown rigor of the studies assessed and the frequent flaws seen of <br /> the studies in this review. <br /> Another recent systematic review looked at how fluoride exposure might be linked to <br /> neurotoxicity specifically in rodents (NTP, 20164) and comes from the Office of Health Assessment and <br /> Translation (GHAT) of the National Toxicology Program (NTP), which is part of the US National <br /> Institutes of Health. In evaluating nearly 70 studies they determined that at levels at or near those used <br /> for community water fluoride supplementation (0.7 mg/L) there was little or no evidence of neurotoxic <br /> effects in experimental animals. In fact, few rodent studies even had data relevant to this fluoride <br /> dosage level. Furthermore, OHAT felt that any future additional studies using this low level of fluoride in <br /> the water would likely be a challenge to perform because fluoride is a micronutrient needed to support <br /> rodent growth, development and adult health and there would be a risk of deficiency. At high doses of <br /> fluoride the studies in this systematic review showed "low-to-moderate evidence of a pattern of <br /> evidence suggestive of an effect on learning or memory" (NTP, 20164) although the studies reviewed <br /> 37 <br />