Check the Facts
Fluoridation:
What the Science Really Says
Community Water Fluoridation & Caries Prevention in Adults
Dr. Gary Slade of UNC School of Dentistry describes his study on the effects of fluoridation on dental caries in Australian adults and discusses implications for the U.S. population and cost-benefit calculations of community water fluoridation.
Recent Reviews
The study found a possible association between fluorosis and IQ. But based on this study’s evidence, no causal relationship can be determined. Potential confounders such as environmental pollutants are not accounted for in the statistical analysis or discussion.
The purpose of this study was to assess whether fluoride levels in bone were associated with osteosarcoma. A case-control design was used to compare bone fluoride levels in 137 subjects with primary osteosarcoma (cases) with 51 controls that had other malignant bone tumors. The median age of cases was 17.6 years old. The median age of controls was 41.3 years old. The gender distribution also differed with 53 percent of cases being male compared to 71 percent of controls. A subset of 32 cases was matched with controls based on gender and age. The study did not demonstrate an association between fluoride levels in bone and osteosarcoma. This was true even after adjusting for age and gender in the statistical analysis in the unmatched cases and controls.
Overall, I can say that if this paper had been sent to me for review, it would not have been accepted for publication.
The major findings in the study indicate that exposure to high levels of fluoride and arsenic is associated with lower IQ. The relationship between high arsenic in drinking water and neurotoxicity is well supported by other research and accepted by the scientific community but that is not the case with fluoride. A carefully conducted animal study failed to show neurotoxic effect on fluoride. The authors could not determine if each child in the high fluoride group actually drank high fluoride water. The authors also did not measure arsenic in the majority of children in the high fluoride group.
The authors examined age-specific and gender-specific effects of fluoride level in drinking water and the incidence of osteosarcoma using a matched case–control study design. The study was conducted through 11 hospitals in the United States that included a complete residential history for each patient and type of drinking water (public, private well, bottled) used at each address.
Their exploratory analysis, based on 103 cases under the age of 20 and 215 matched controls, plotted the impact of different assessments of exposure for the cases and controls. This method showed that by using fluoride level at each of the ages 4 to 12 years as the exposure definition, there was an increased adjusted odds ratio for males in the higher fluoride exposure group. The adjusted odds ratio was high... Read More