Exposure to fluoride may lower children's intelligence...
According to Paul Connett, Ph.D., director of the Fluoride Action Network, "This is the 24th study that has found this association, but this study is stronger than the rest because the authors have controlled for key confounding variables and in addition to correlating lowered IQ with levels of fluoride in the water, the authors found a correlation between lowered IQ and fluoride levels in children's blood. This brings us closer to a cause and effect relationship between fluoride exposure and brain damage in children."
In this study, 512 children aged 8-13 years in two Chinese villages were studied and tested – Wamaio with an average of 2.47 mg/L water fluoride (range 0.57-4.50 mg/L) and Xinhuai averaging 0.36 mg/L (range 0.18-0.76 mg/L).
The authors eliminated both lead exposure and iodine deficiency as possible causes for the lowered IQs. They also excluded any children who had a history of brain disease or head injury and none drank brick tea, known to contain high fluoride levels. Neither village is exposed to fluoride pollution from burning coal or other industrial sources. About 28% of the children in the low-fluoride area scored as bright, normal or higher intelligence compared to only 8% in the "high" fluoride area of Wamaio.
In the high-fluoride city, 15% had scores indicating mental retardation and only 6% in the low-fluoride city.
The study authors write: "In this study we found a significant dose-response relation between fluoride level in serum and children's IQ."
