John W Travis in his letter to the Echo re fluoridation (December 30) writes that we should look at the facts. OK let’s look at the evidence he cites in his letters.
First he says that fluoridation is plot by industry to dispose of its toxic waste products at public expense. Wrong. Fluoride is made from hydrogen fluoride and fluorosilicic acid which are not waste products but valuable chemicals, produced to high purity by fractional distillation and have many uses. Over one million tons of these chemicals are produced a year.
Secondly he says no controlled studies exist and selectively quotes the NSW Dept of Health to wrongly suggest that there is no evidence for the efficacy of fluoride. The full quote is: ‘Although there are no randomised controlled trials of fluoridation of the water supply, there have been other well-designed studies as detailed and summarised in the NHMRC’s A Systematic Review of the Efficacy and Safety of Fluoridation (pdf). The NHMRC review is also on the web.
He requires controlled trials and ignores well designed studies but what evidence does he use to support his position? It’s the Harvard meta-analysis – but he misrepresents this too. This paper reviewed 26 studies in China and one study in Iran (none was a controlled trial) and using the results of these studies reported that children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. Travis reported this as ‘fluoride exposure at only modestly raised levels significantly decreases the IQ of the children’. Did he read the paper?
Also if he has read the Harvard study he should know that it is based on a lot of poor science. It noted that each of the 27 studies ‘had deficiencies, in some cases rather serious ones’. I have looked at a lot of these studies and am surprised that an Australian academic would unquestionably accept them. Even one anti-fluoride website admitted that ‘many of the fluoride/IQ studies have used relatively simple designs and have failed to adequately control for all of the factors that can impact a child’s intelligence (e.g., parental education, socioeconomic status, lead and arsenic exposure)’. The authors of the Harvard paper only say their results support the possibility of adverse effects and that more research is required.
Professor Travis ignores the fact that for more than 60 years hundreds of millions of people have been drinking fluoridated water with no adverse effects on IQ and instead offers 27 obscure papers of questionable scientific rigour and misrepresents their results. He also misrepresents the source of fluoride and its benefits to dental health. I hope this is not the type of science he is teaching at RMIT.
Rob Watson, Myocum