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Expert Evaluation by Ann Newman Chelminski MPH, MD. <br /> There have been a number of studies published in this area in the past decade, some suggesting <br /> an association of lower IQ in children whose mothers had higher prenatal fluoride exposure. It should be <br /> noted that some of the studies listed in the CADTH' review (Table 36, p. 168) were conducted in <br /> countries with areas of very high levels of naturally-occurring fluoride in water. In some studies, the <br /> comparison (low exposure) subjects had drinking water with fluoride concentration higher than the US <br /> standard for community water supplies. Most of these studies found an association between high water <br /> fluoride concentrations and lower IQ. The high exposure groups had levels significantly higher than the <br /> US community water standard. A meta-analysis by Choi et a12 in 2012 reviewed studies done in rural <br /> China in communities with some very high (>10ppm) levels of fluoride in drinking water. Higher fluoride <br /> exposure was associated with lower IQ measurements. The authors note that most of the studies were <br /> of poor quality. Another study by Choi et a13 of 51 children in China found an association of moderate to <br /> severe dental fluorosis (indicating higher fluoride exposure) and poorer scores on a test of non-verbal <br /> learning and memory (digit span test). Aggeborn and Ohman4 looked at subjects > age 16 in Sweden <br /> and found no effect of water fluoridation on cognitive ability and math skills. A more recent study from <br /> 2019 by Green et a15 in Canada is noteable in that the level of exposure was comparable to the levels of <br /> fluoride found in U.S. community water systems. The authors conclude that increased maternal fluoride <br /> exposure is associated with decreased IQ in children at age 3-4. However, as the CADTH' review authors <br /> note, this conclusion is not supported by the data presented. There was no association in girls, only in <br /> boys. The difference between control and exposure groups for boys was not large. For girls, the IQ <br /> scores were slightly higher in the exposed (fluoridated) group. A 2017 study by Bashash et a16 in Mexico <br /> City looked at women enrolled in different cohorts for a study of environmental exposures during <br /> pregnancy. The biomarker for fluoride exposure was maternal urinary fluoride adjusted for creatinine <br /> 26 <br />