The coalition that is promoting water fluoridation in Portland has published a video that I found quite interesting: Portland Fluoride: Facts Vs Fiction.
The video features Portland Pediatrician Dr. Phil Wu at Kaiser Permanente, and he debunks false and misleading anti-fluoride claims—according to the description. Dr. Wu addresses claims made by another pediatrician, Dr. Yolanda Whyte, and I encourage you to watch the video and then read on!
Therefore, I was surprised by Dr. Wu's dismissal of the research that associate fluoride with reductions of children's intelligence. Let me quote directly from the video, starting at 3 minutes and 4 seconds:
Dr. Whyte says:
My concern is based in part in a large body of research finding that modestly elevated levels of fluoride can reduce a child's intelligence.Dr. Wu responds:
This may be the most serious misrepresentation of all. This article, often cited by anti-fluoride activists, reviewed studies from China, Mongolia and Iran, including water samples in which the natural fluoride levels were 400 to 1200 percent higher than the recommended level for fluoridating water in the U.S. The Harvard researchers who examined these fluoride IQ studies took the unusual step of publicly distancing themselves from the claims that anti-fluoride groups were making about these studies.The video then shows the following quote:
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| Harvard scientists: Data on fluoride, IQ not applicable in U.S. "These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S.," |
On his blog, Dr. Grandjean spells out something that I think should be hard to miss for anyone who has read and understood the Harvard study:
Chemical brain drain should not be disregarded. The average IQ deficit in children exposed to increased levels of fluoride in drinking water was found to correspond to about 7 points – a sizable difference. To which extent this risk applies to fluoridation in Wichita or Portland or elsewhere is uncertain, but definitely deserves concern.Now, I can understand that laymen who were concerned about the reports around fluoride and IQ would put their concerns to rest after seeing the Wichita Eagle statements.
But I would expect something different from a pediatrician who speaks out publicly on the issue of fluoride safety than simply dismissing a potential neurotoxic hazard to our children by referring to newspapers in Kansas. That shows a complete lack of diligence and is unprofessional beyond comprehension. In particular since Dr. Wu noted that it was an "unusual step" for the authors of the IQ study to publicly distance themselves. Think about it for a second. Why would the Harvard researchers attempt to publicly correct misrepresentations of their research by using a Kansas newspaper? The obvious step for Dr. Wu would have been to contact the authors directly to confirm the newspaper claims.
Dr. Wu was one of the experts responsible for the presentation before the Portland City Council in September 2012, and a week later the Council decided that water fluoridation was safe and effective and approved an implementation plan that will affect 900,000 people in an around Portland.
I am wondering to what extent the Council based their decision on rumours in newspapers instead of current research. The thought is chilling.
From now on, I believe in policy making based on evidence rather than endorsement.
I am looking forward to seeing statements from Dr. Wu, the American Academy of Pediatrics, and the Oregon Pediatric Society where they specifically address the results from Dr. Grandjean, and explain why we do not need to establish a safe limit for fluoride in drinking water which would guarantee that our children do not suffer from chemical brain drain.
At least until then, it would be completely irresponsible to support further expansion of community water fluoridation. And until then, my motto will be:
An apple a day keeps the doctor away.
Take your doctor's words with a grain of salt.
What surprised me a bit is the assertion that a factor of five would be enough to avert risk, especially for a rather serious cognitive effect. Usually when safety standards are determined in processes that are do not have a well understood mechanism larger factors are used.
ReplyDeleteThe Harvard paper was not a study, rather a meta analysis. The authors wrote the Wichita Eagle warning that voters shouldn't use their study to decide whether to put fluoride in the city’s drinking water to fight tooth decay. Read more here: http://www.kansas.com/2012/09/11/2485561/harvard-scientists-data-on-fluoride.html#storylink=cpy Meta analyses of randomized controlled studies have a 35% inaccuracy when compared to the eventual large well designed study. Meta analyses of ecologic epidemiological studies are very weak evidence. The meta-analysis credibility hinges on whether good-quality studies are reviewed. T co-authors specifically state "each of the [studies] reviewed had deficiencies, in some cases rather serious, which limit the conclusions that can be drawn."
ReplyDeleteSpecific concerns about these studies include:
80% of the used water fluoridation concentration as the low fluoride reference . .that is the normals were fluoridated water
20% studied environmental fluoride pollution, not drinking water
15% were complicated by arsenic and lead, and the others did not seek information about those possible cofounders
Only one of the papers was published in a western peer reviewed journal, they were not subjected to the critique or review which is a routine expectation.
Cofounders, a very vexing problem for IQ research were considered in only 2 studies.
Additionally previous western research suggests no correlation between lower IQ and the fluoride concentrations of fluoridation.
http://www.ncbi.nlm.nih.gov/pubmed/3461356
N Z Med J. 1986 Jun 11;99(803):416-8.
Exposure to fluoridated public water supplies and child health and behavior.
Shannon FT, Fergusson DM, Horwood LJ.
The only Chinese paper to compare low, fluoridation and high fluoride found that IQ was optimized with fluoridation concentrations. "By testing of the intellectual ability of 447
elementary school students ranging in age from 9 to 10 1/2, it was discovered that both high and low fluoride had an effect on child intelligence. Fluoride levels greater than 2.0 mg/L or less than 0.2 mg/L can disrupt intellectual development." Qin LS, Cui SY. (1990). The influence of drinking water fluoride on pupils IQ, as measured by Rui Wen's standards. Chinese Journal of the Control of Endemic Diseases 5:203-204.
It is not reasonable to argue that these Chinese papers should set public health policy for the USA. All the Harvard authors argue for is for additional research. That their study didn't "prove" no connection between fluoride and IQ is completely obvious and of not importance to the decision for water fluoridation. That research really concerns high fluoride exposures, not 0.7 ppm as proposed for PDX.
BillyBudd - thank you for pointing out that the Harvard paper is not a study in itself. I will call it the Harvard review from now on.
ReplyDeleteI am not sure why you bring up the arguments from the Wichita Eagle again, I apologize if I wasn't clear enough in my post. Let me quote senior author Philippe Grandjean's blog entry where he in a rather understated manner writes:
"However, neither newspaper checked their information with the authors, even though statements were attributed to them."
You bring up some research that points to no correlation between fluoride exposure and child behaviour, and then some research that shows that fluoride might affect IQ. I am confused. Do you think that fluoride in drinking water has an impact on cognitive development, or not?
Thank you!
The point is that everyone agrees that the Chinese studies are very flawed. The authors of the Choi et. al. paper never concluded that fluoride, even at high levels causes lower IQ, just that we need to do more research, which sounds like a good thing to do.
DeleteAlso, it is important to note that Grandjean is the 4th of 4 authors on the paper, and that Choi is the corresponding author and the one that is designated to represent the conclusions of the study to press and others. It sounded like the Wichita Eagle got an email from Choi with the quote in it. I find it hard to believe that the paper misquoted him if it came from an email.
Mel, the Chinese studies have flaws, and indeed more research is needed.
DeleteBut what do we do until that difficult piece of research has been done? As I have pointed out in a comment on an earlier post, I would like to highlight the precautionary approach that Grandjean and Landrigan have motivated, and I wonder how many indications we need before taking action.
Regarding the details behind the quotes in the Wichita Eagle: I don't consider it important to find out to what extent the quotes are accurate. My main concern is that in Dr. Wu's role, it is wrong to dismiss scientific research based on newspaper material instead of taking the actual research into account.
Let me repeat the last sentence of Grandjean and Landrigan's precautionary approach:
"As physicians, we should use prudence when counselling our patients, especially pregnant mothers, about avoidance of exposures to chemicals of unknown and untested neurotoxic potential."
I am looking forward to hearing Dr. Wu addressing the Harvard review in a way that takes the precautionary approach into account.
That would be a great step toward restoring credibility for the organizations that Dr. Wu represents, namely the Oregon Pediatric Society and the Healthy Kids, Healthy Portland campaign.
Mel, I share your vision in that I think we have a golden opportunity to raise awareness about the dental health of our children in Portland in our upcoming vote. Let's just make sure we take all relevant scientific research into account so that we don't throw out the baby with the bathwater.
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ReplyDeleteHere's an excerpt from an article I wrote about this issue:
ReplyDeleteThe majority of the studies that the Harvard team reviewed investigated fluoride levels that are still considered “safe” in the United States. Of the twenty studies that investigated the effect of fluoride intake from water, twelve examined communities with a fluoride content less than 4 mg/l. This is a level that is still considered “safe” by the U.S. EPA. Every one of these twelve studies found reduced IQ in the “high-fluoride” community when compared to a low-fluoride community. Of these twelve studies:
Seven studies found reduced IQs among children drinking water with fluoride levels between 2.1 mg/l and 4 mg/l — levels that 1.4 million Americans drink everyday. (Poureslami 2011; Seraj 2006; Hong 2001; Wang 2001; Lu 2000; Yang 1994; An 1992)
Four studies found effects at levels between 1.8 mg/l and 2.0 mg/l — levels that about 600,000 Americans drink everyday. (Xiang 2004; Yao 1997; Yao 1996; Xu 1994)
One study (sponsored by UNICEF) found reduced IQ at just 0.88 mg/l – a level within the “optimal” range of fluoride that is added to the drinking water of over 200 million Americans. (Lin 1991)
Far from being irrelevant to U.S. exposures, these fluoride levels are actually being consumed on a regular basis by millions of Americans. Further, the fluoride levels that were detected in the children’s urine in five of these studies (1.5 to 3 mg/l) were found to be exceeded by many adults living in fluoridated populations in England. (Mansfield 1999) While there is a striking absence of urinary fluoride data among both children and adults in the United States, the high exposure to fluoride toothpaste among young children is almost certain to produce urine fluoride levels that match the levels documented in the Chinese children.
Another population at clear risk from fluoride are children born to women who drink large amounts of low-quality teas. Research from China has repeatedly found that high fluoride exposure during pregnancy can damage the brain of the fetus in ways that can permanently reduce the intelligence of the child. (Yu 1996; Dong 1993; Du 1992; Han 1989) Damage to fetal brain has been found in women with urinary fluoride levels of just 4.3 ppm. (Yu 1996). Notably, this is a level of fluoride that heavy tea drinkers in the U.S. and England are known to exceed. (Izuora 2011; Whyte 2005; Mansfield 1999). The neurological impact of heavy-tea consumption during pregnancy has never been studied.
Michael, thank you for your excerpt. The indications of developmental neurotoxicity are accumulating.
ReplyDeleteOne can easily get lost when discussing different exposure levels, but at the moment I would like to recall the precautionary approach that Philippe Grandjean nicely captured in this quote from his Lancet 2006 review:
"Prevention of neurodevelopmental disorders of chemical origin will need new approaches to control chemical exposures. The vulnerability of the human nervous system and its special susceptibility during early development suggest that protection of the developing brain should be a paramount goal of public health protection. The high level of proof needed for chemical control legislation has resulted in a slow pace of interventions to prevent exposures to lead and other recognised hazards. Instead, exposure limits for chemicals should be set at values that recognise the unique sensitivity of pregnant women and young children, and they should aim at protecting brain development. This precautionary approach, which is now beginning to be used in the EU, would mean that early indications of a potential for a serious toxic effect, such as developmental neurotoxicity, should lead to strict regulation, which could later be relaxed, should subsequent documentation show less harm than anticipated. As physicians, we should use prudence when counselling our patients, especially pregnant mothers, about avoidance of exposures to chemicals of unknown and untested neurotoxic potential."
Magnus, as usual, great discussion.
ReplyDeleteFluoridation defenders seem to have blinders for this issue of developmental neurotoxicity. Oversimplified arguments and claims abound. Canada's main public health promoter of fluoridation once famously said, "I don't see people walking around with horns sticking out of their heads" in a fluoridated city, by which he meant he didn't think there was any substance to charges that fluoridation might have harmful health effects.
In regard to the Choi, Grandjean, and related scientific evidence on IQ, the fluoridation defenders seem to be saying "If you can't prove there is a 7 IQ point decline at 0.7 mg/L F in water, then you don't have strong enough evidence to question fluoridation".
I'm sure, when and if higher quality studies are conducted of fluoride and IQ, the effect will be much more subtle and difficult to detect with anything but the most sensitive and high quality studies. For example, perhaps the 10% of the 10% of those who are iodine deficient and who drink a lot of water will be the ones with detectable drops in IQ. That adds up to 1% of the population. The other 99% might average 1 or 2 IQ point drop, but that would be very difficult to detect. If the study doesn't focus on the most at-risk subgroups, it may well not detect any effect.
These are numbers off the top of my head.
But what are the implications for such a finding? If 1% of the 200 million Americans who are on fluoridated water were to have their IQ reduced by, say, 7 points, that is 2 million people. How could the purported dental benefit of about a half a cavity per child be acceptable if the "collateral damage" is 2 million people with IQ reduced to a degree that their entire life they will be a big step behind what they could have been.
If fluoridated water allowed for individual, informed choice, then such tradeoffs could be acceptable. But no person, no government, and not even a plurality of voters should have the right to make such a decision for others.
Magnus: FAN has produced a response to Dr. Wu's attack video against Dr. Yolanda Whyte. It can be viewed here:
ReplyDeletehttp://www.youtube.com/watch?v=30umO7s4Zj0&feature=player_embedded
You and your readers can judge for themselves which side is more credible.