Rooster syndrome and the anti-fluoride crowd.
I live in a part of the world where the print media is dominated by Murdoch publications, and since I am no longer prepared to pay money to support the evil empire, I have a shortage of good sources of analysis. Recently I noticed a newsstand offering free copies of the Epoch Times and decided to give it ago. Until today, I was quite impressed – good coverage of Chinese politics and even some local stuff. I’d almost overcome my skepticism about the its mysterious source (Is it a Falun Gong propaganda rag?). But then, in the latest edition, I came across an article with the headline: Water fluoridation affects children’s IQ.
This article was written by W. Gifford-Jones, M.D. (apparently the pen-name of Dr. Ken Walker, a Toronto gynecologist), and he focuses on a recent study (here) from the Harvard School of Public Health. The study has also been headlining at all the anti-fluoridation websites, which are gleefully claiming it justifies their stance. It is in fact a systematic review, based on 27 studies, mostly carried out in China. The authors’ Conclusion is as follows:
The results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment. Future research should include detailed individual level information on prenatal exposure, neurobehavioral performance, and covariates for adjustment.
But in a classic case of rooster syndrome, Gifford-Jones writes:
Now, a report from the Harvard School of Public Health (HSPH), says that the use of fluoride causes a decrease in children’s IQ.
This is nonsense, of course. There is no finding of cause and effect. The study found a correlation between fluoride concentrations and IQ, and sensibly, the authors recommend that further investigation is required. They acknowledge that there are many sources of uncertainty – including that “each of the articles reviewed had deficiencies, in some cases rather serious ones” and “the estimated decrease in average IQ … may seem small and may be within the measurement error of IQ testing”. (A HSPH press release points out that the average discrepancy corresponded to about 7 IQ points). John Underhay at Skeptic North and Steven Novella at Science-Based Medicine have further quibbles.
Gifford-Jones goes on to claim:
Researchers discovered that children in the low-fluoride area had a 28 percent chance of being normal, bright, or of high intelligence.
In the high-fluoride area, the figure was 8 percent. They also found that in the low-fluoride community, 6 percent of children suffered from mental retardation compared to 15 percent in the high-fluoride community.
yet these figures appear nowhere in the paper.
So I’m pretty disillusioned with the Epoch Times. There’s no excuse for poor science journalism.