Tag Archives: China

New study touted by anti-fluoridation campaigners actually indicates fluoridation is safe

Children used in this study were from Lintingkou town (a normal-fluoride/control area) and Dakoutun town (a high-fluoride area) in Baodi district of Tianjin, China. The towns are 25 km apart.

Anti-fluoridation activists on social media seem to cite any scientific article about fluoride which they think will show it harmful. They usually rely only on information in the article title or abstract. This means they are often wrong as the articles may not be at all relevant to the low fluoride concentrations used in water fluoridation. Perhaps they should stop for a minute and actually read the articles they cite.

The other day @NYSCOF, the twitter account for the New York State Coalition Opposed to Fluoridation, Inc (a small antifluoridation activist group in New York) promoted a new Chinese study as part of its campaign against community water fluoridation (CWF). It claimed: “Children’s IQ was lower when water and urinary fluoride levels were high compared to a low fluoride group.” But the fact this is a Chinese study should have warned the honest reader that the “high” fluoride group lived in an area of endemic fluorosis and data for them is irrelevant to CWF.

In fact, some of the data in their paper are relevant to CWF – the data for the “low fluoride” control group where children were exposed to drinking water concentrations less than 1 mg/L (CWF aims to maintain a drinking water fluoride concentration of about 0.7 or 0.8 mg/L). It’s worth looking at that data to see if child IQ is related to fluoride exposure at that level.

The take-home message is that it isn’t.

Here is the citation for the new study:

Zhao, Q., Tian, Z., Zhou, G., Niu, Q., Chen, J., Li, P., … Wang, A. (2020). SIRT1-dependent mitochondrial biogenesis supports therapeutic effects of resveratrol against neurodevelopment damage by fluoride. Theranostics, 10(11), 4822–4838.

Two different communities

The children (8-12 year-olds) in this study came from two different communities in the Baodi district of Tianjin, China – see the map above. They are Lintingkou town, where drinking water fluoride concentrations were “normal,” and Dakoutun town, which is in an area of endemic fluorosis and the drinking water fluoride concentrations are high (about 1 to 3.5 mg/L). The towns are about 25 km apart and will clearly have a number of differences which could be relevant to the IQ of children. Possible confounders like this were not considered in the study.

People living in areas of endemic fluorosis suffer a range of health and socioeconomic effects which could influence child IQ

The figure below from the paper illustrates the ranges of drinking water F and urinary F for the children studied (30 in each of the “low” and “high” fluoride groups).

Only the data for the “control” group are relevant to CWF. Unfortunately, the authors chose to plot the IQ data for the two groups on the same graph and concluded that this showed a “fluoride-caused intellectual loss in children” – see their graph below.

But, their conclusion is wrong. When we look at the data for the “control” and “high fluoride” groups separately that simple conclusion is clearly unwarranted.  In fact, there is no statistically significant relationship (p<0.05) of child IQ with urinary F for either the “low” or the “high” group – see the graph below which uses digitally extracted data from the above figure. Data points for the”low” fluoride group are green and those for the “high” fluoride group are red.

This shows how statistical analyses like regression analyses can produce misleading results if the data is not considered properly. It is simply misleading to include two separate populations like this in a regression analysis without considering the whole range of possible confounders.

There is no relationship between child IQ and urinary fluoride in either population. All the regression analysis shows is that there is a difference between the two towns – and that is simply shown by the average values of IQ in those towns. The average child IQ in Lintingkou town is 112.4 while in Dakoutun town it is 98.5.

While these IQ values seem pretty good (usually the average IQ for a population is 100) the lower value for Dakoutun town is not surprising considering that the population living in areas of endemic fluorosis suffer a whole range of health and social problems.

The biochemical data has the same problem

The paper itself is a real hodgepodge of separate studies involving child IQ, levels of mitochondrial biogenesis signalling molecules, experiments with rats and with in vitro cell cultures. I do not have the expertise to critique the biochemical, cell culture and rat behavioural techniques used. However, the presentation of the biochemical data for the children suffers the same problems as the presentation of the IQ data.

The authors claim that there is a significant positive relationship between the silent information regulator 1 (SIRT1) and child urinary F, and significant negative relationships of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and mitochondrial transcription factor A (TFAM) with child urinary F. But they simply lumped the data for the two towns together. When the data for the two groups are considered separately there are no statistically significant relationships for these biochemical measures in either of the two groups – see figures below. Again, data points for the “low” fluoride group are green and those for the “high” fluoride group are red.


Yet against anti-fluoride campaigners are promoting a study that they probably haven’t even bothered reading. They are using results for an area of endemic fluorosis to argue against CWF. Worse, they are completely ignoring the data in this and similar studies which show no relationship between child IQ and fluoride exposure at fluoride levels relevant to CWF.


The Twitter account @NYSCOF promoting this specific study is very active and is connected with the Fluoride Action Network (FAN) through Carol Kopf –  the media officer for both the New York State Coalition Opposed to Fluoridation, Inc. (NYSCOF) and FAN. Ironically, she uses the slogan “I Am a Force for Science” on her Twitter image.

Sometimes I drop a reply to her posts – in this case pointing out: “And no loss of IQ at F concentrations relevant to community water fluoridation. These studies show CWF safe.”

My comment will not change Carol Kopf’s mind, of course, but others may read it and understand. Mind you, it’s inevitable that other anti-fluoride activists see my comments and react in stupid ways. For example, one of the Fluoride Free NZ leaders, Kane Kitchener, posted this reply:

“Ken, you’ve been exposed too long by Hamilton’s Fluoridated water. Too much reduction in IQ to see it.”

It really is pointless attempting to discuss science with these people.

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A Chinese study the anti-fluoridation crowd won’t be citing


Tooth brushing programme carried out in kindergartens in a Chinese rural area. Image credit: Supervised tooth brushing programme

Anti-fluoridation campaigners love to cite Dr Q. Y. Xiang to “prove” that community water fluoridation (CWF) can lower IQ. Trouble is – Xiang’s research on fluoride and IQ took place in an area of endemic fluorosis in China where drinking water fluoride levels were much higher than those used for CWF. That hasn’t stopped Paul Connett from making mileage out of Xiang’s data – even though the link between IQ and drinking water fluoride shown by Xiang’s data is very tenuous (see Connett fiddles the data on fluoride).

However, I suspect Connett and his activist organisation, The Fluoride Action Network (FAN), will be very quiet about the latest paper from this group. This is because the research they report supports the scientific consensus – in particular:

  • Fluoride at the concentration used in CWF does reduce tooth decay;
  • Fluoride at the concentration used in CWF does not cause the cosmetically undesirable forms of  dental fluorosis.

The paper is:

Xiang, J., Yan, L., Wang, YJ., Qin, Y., Wang, C. &  Xiang, QY. (2016). The effects of ten years of defluoridation on urinary fluoride, dental fluorosis, defect dental fluorosis, and dental caries, in Jiangsu province, PR China. Fluoride, 49(March), 23–35.

Yes, I know, it is published in Fluoride – which is hardly a credible scientific journal. And the lack of proper peer review sticks out like a sore thumb with mistakes in the text, poor data presentation and poor data statistical analysis.

Fluoride improves dental health

This is shown by data they collected in 2002 for two villages -Wamiao (a “severe endemic fluorosis village” with drinking water fluoride in the “range of 0.57 – 4.50 mg/L”) and Xinhuai (a “non-endemic fluorosis village” with drinking water fluoride in the “range 0.15 – 0.77 mg/L”). They combined the data for the 2 villages to produce the following graphic – from which they concluded that a “possible desirable range for the fluoride level for minimizing the prevalence of dental caries” . . .  [is] “approximately 1.5 – 2.5 m/L.” Considering this is just one study and has limitations the result is similar to the recommended fluoride level for CWF – 0.75 mg/L in the USA and 0.75 – 1.2 mg/L in New Zealand.

DMFT Xiang

OK, this is a poor graphic and I cannot see why they should have divided the data into the nine subgroups instead of statistically analysing the whole dataset (an indication of poor peer review by the journal?). But you get the picture. Dental decay declines as fluoride concentration in the drinking water in increased from near zero to about 1 mg/L.

CWF does not cause dental fluorosis

After 2002 the water sources used in the two villages changed:

“As a defluoridation project, water from two deep wells has been used as a tap water source of drinking water in Wamiao village since the beginning of 2003. The surface water in Yaohe river has been used as a tap water source in Xinhuai village since 2009.”

The current dental fluorosis study occurred in 2013 when the fluoride concentrations in both villages were in the range 0.85 – 0.95 mg/L. This is similar to the levels used in CWF.

In 2013, the researchers found very low levels of total dental fluorosis in both villages (3.1% in Xinhuai and 8.8% in Wamiao – no significant difference). They also measured “defect dental fluorosis” – a Chinese classification which includes some “moderate” dental fluorosis and all “severe dental fluorosis as diagnosed by Dean’s criteria (see  Water fluoridation and dental fluorosis – debunking some myths and the image below).

The prevalence of “defect dental fluorosis” in 21013 was zero for both villages.

This contrast markedly with the situation in 2002 where the prevalence of total dental fluorosis was significantly higher in Wamiao village (89%) than in Xinhuai (4.5%). The prevalence of “defect dental fluorosis” was 39% in Wamiao but zero in Xinhuai (data from Xiang, et al., 2004).

The 2013 data reported in this paper confirm what I have said again  and again in  articles here. CWF does not cause the cosmetically undesirable forms of dental fluorosis – the “moderate” and “severe” forms, or the “defect dental fluorosis” in the Chinese classification). Anti-fluoride campaigners always misrepresent this data by quoting figures for total dental fluorosis and claiming the effects are those only seen with “moderate” and “severe” forms.

Paper’s take home message

The new water supply in these two villages has solved the dental fluorosis problem while also maintaining a fluoride concentration comparable to that used in CWF and helping support a low level of dental decay in children. The data support other findings (and the current scientific consensus) showing that CWF does not cause any cosmetically undesirable dental fluorosis but does help prevent tooth decay.

Unusual photo of Moon and Earth.

Here’s a photo of the earth you don’t often see. Nor is the view of the moon familiar.


The Chinese test vehicle Change’5 took this photo as it swung around the moon before returning to earth.  So we see the unfamiliar far side of the moon, with the earth in the distance.

AS Phil Plait commented:

“For just a fleeting moment I could have been convinced someone had added a photo of the planet Mercury here; the Moon’s obverse half is so strikingly different than the near side. The lack of dark maria (except for Mare Moscoviense to the upper left) makes the Moon look like every bit the alien world that it really is.”

Emily Lakdawalla displays this and some other photos taken by Change’5 in a recent blog article Chang’e 5 T1 rounds the lunar farside, returns lovely photo of Earth and the Moon together.

After an 8-day mission Change-5 landed safely in Siziwang Banner of China’s Inner Mongolia Autonomous Region.

China is only the third nation to demonstrate lunar return technology following the former Soviet Union and the United States. The Soviet Union conducted the last lunar return mission in the 1970s.


Researchers retrieve the return capsule of China’s unmanned lunar orbiter in the central region of north China’s Inner Mongolia Autonomous Region, Nov. 1, 2014. Return capsule of China’s test lunar orbiter landed successfully early Saturday morning in north China’s Inner Mongolia Autonomous Region, according to the Beijing Aerospace Control Center. Credit: Xinhua/Ren Junchuan

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Quality and selection counts in fluoride research

I think the paper most quoted by anti-fluoridation activists must be Choi et al (2012), Developmental fluoride neurotoxicity: A systematic review and meta-analysis. I say quoted but, I suspect, not read. It is always coming up in articles on natural health web sites and continually thrown into blog and Facebook discussions. Often as a link without explanation.

It is also heavily promoted on Twitter. The same tweet is often sent from the same account daily, or more often. Here are examples.

Harvard Study: #Fluoride Lowers Children’s Intelligence By Seven IQ Points
Harvard Study Confirms Fluoride Reduces Children’s IQ huff.to/111fe5o via @HealthyLiving
Harvard Study Confirms Fluoride Reduces Children’s IQ: articles.mercola.com/sites/articles…

The paper also gets a lot of mention when anti-fluoride activists petition local bodies to prevent or stop fluoridation. It was one of the papers that had a big effect on the Hamilton City Council during the hearings they held last year (see When politicians and bureaucrats decide the science).

I recently reread the paper – this time paying special attention to the selection and quality of the papers reviewed. I think both of these are important to anyone attempting to understand the significance of this review.


Choi et al (2012) selected 27 papers for their review. Their selection was clearly not random – 25 of these are Chinese studies with 2 Iranian. Very few of these papers are directly available to western readers. One of the Iranian papers has an English abstract and 3 of the Chinese studies were published in English (guess which journal – you are right – Fluoride). 

The authors do not give any details of translation of the papers but 8 of them seem to have been translated under the auspices of Paul Connett’s Fluoride Alert (FAN) activist group (FAN describes them as the “FAN English translation”). Copyrights for these English translations are held by the International Society for Fluoride Research (ISFR) and included in their journal Fluoride. They are also available on FAN. (It is sort of difficult to locate the boundaries between FAN, ISFR and Fluoride. And did you know the ISFR has charity status in New Zealand. Yes, as taxpayers we are subsidsing them through their tax exemption!).

The authors acknowledge the reviewed studies were selected and give several reasons:

1: Studies from rural China had not been included in earlier reviews:

“We specifically targeted studies carried out in rural China that have not been widely disseminated, thus complementing the studies that have been included in previous reviews and risk assessment reports.”

2: High fluoride concentrations in drinking water are not common in the west:

“Opportunities for epidemiological studies depend on the existence of comparable population groups exposed to different levels of fluoride from drinking water. Such circumstances are difficult to find in many industrialized countries, because fluoride concentrations in community water are usually no higher than 1 mg/L, even when fluoride is added to water supplies as a public health measure to reduce tooth decay.”

Well, I can understand the logic behind that selection – provided readers don’t think they are seeing a balanced, representative review of all the existing literature. And the reasons given for this selection makes nonsense of Paul Connett’s charge that the lack of material in the industrialised countries indicates at least an unwillingness to research problems or at worst a conspiracy not to do the research and/or hide the results.


Here I will just take the size of the reviewed reports as a possible indicator of their quality. Not that I am against short papers, far from it. But in this cases most of the papers were very short – basically because they reported only a simple relationship found between IQ and fluoride in drinking water. Very few papers consider confounding factors like family education, schooling, breast-feeding, etc. Factors known to influence IQ. Nor did they discuss their results in any depth.

The authors acknowledge the brevity of the reports reviewed:

“In regard to developmental neurotoxicity, much information has in fact been published, although mainly as short reports in Chinese that have not been available to most expert committees.”


“Although most reports were fairly brief and complete information on covariates was not available, the results tended to support the potential for fluoride-mediated developmental neurotoxicity at relatively high levels of exposure in some studies.”

The histogram below gives an idea of the size of these reports – obviously some were extremely short –  19 of the 26 considered were of 3 pages or less!


Another reason for brevity is that most papers give hardly any discussion, let alone critical assessment, of the reported results. I wonder if this is because of the well-known problem of excessive levels of fluoride in many Chinese well waters and the associated incidence of dental and bone fluorosis. Perhaps this encourages researchers to simply consider fluoride as a factor in other problems when we might think it more rational to look at factors traditionally related to IQ. Like education and breastfeeding.

Even Paul Connett has conceded the poor quality of many of the studies considered in this review (while of course still scare-mongering that fluoridation is somehow going to make us all dumb). The authors of the study itself warned their paper was not relevant to the fluoridation issue (see Harvard scientists: Data on fluoride, IQ not applicable in U.S):

“Two of the scientists who compiled the Harvard study on fluoride said it really doesn’t address the safety of fluoridation levels typical of American drinking water.

“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.,” the researchers said in an e-mail response to questions from The Eagle. “On the other hand, neither can it be concluded that no risk is present.”

The researchers noted that the fluoride levels they studied were much higher than what is found in fluoridated water in the United States and recommended “further research to clarify what role fluoride exposure levels may play in possible adverse effects on brain development, so that future risk assessments can properly take into regard this possible hazard.””

I guess this paper, and its continual promotion, must impress many anti-fluoridation activists and even some local body councillers and staff. But scientists and other experts familair with the subject are not so impressed.  The NZ National Fluoridation Information service last year reviewed  literature on possible effects of fluoridation on IQ (see A review of recent literature on potential effects of CWF programmes on Neurological ):

“The available evidence raises the possibility that high levels of fluoride in drinking water may have subtle effects on children’s IQ. However all of these studies have limitations in design and analysis, a clear dose-response relationship between DWFCs and assessed IQ are often not evident. The study authors are frequently very cautious in their comments, and several noted that any indicated negative effect applied only to high DWFCs. An hypothesis of fluoride neurotoxicity would also be supported by some experimental animal studies, however the great majority of these have only considered high fluoride intakes.
However collectively the data described are not robust enough to draw a firm conclusion that high fluoride levels in drinking water supplies contribute to retarded development of children’s brains. Also there is no clear evidence to suggest an adverse effect on IQ at lower fluoride intakes such as that likely to occur in New Zealand, where fluoridated water supplies contain fluoride in the 0.7 to 1.0 mg/L range.”

Since then a local New Zealand study has failed to find any relationship between fluoridation and IQ (see Dunedin fluoride-IQ study finds no ill-effect). The study did find a positive influence of education and breast feeding on IQ though – just as we would expect.

In a typical sour grapes comment Paul Connett, who was told of this research by a reporter, quipped “rather convenient.”

Confirmation bias in action! I guess he won’t be promoting the New Zealand research in the way he does the poor quality research in the Choi et al (2012) review.

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Back to the moon!

Well, this is pretty historic!

China has successfully soft landed its probe on the moon and the rover is now on the surface.

The Planetary society’s Emily Lakdawalla has posted TV video of the unloading of the Rover – see Six wheels on soil for Yutu!

These are 3 animated gifs from Emily’s article

20131214_change3_rover_deploy_final 20131214_change3_rover_deploy_2_transfer 20131214_change3_rover_deploy_1_roll

For those wanting to follow the process in real-time this is the video from the TV coverage.

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Fluoridation – the IQ myth

fluoride_kills_test (1)Some of the myths promoted by anti-fluoridation activists really are of the “unsinkable rubber duck” variety. No matter how many times they are debunked they keep being repeated.

If you follow the fluoridation debate at all you will have come across the “Harvard Study” “proving” fluoride makes you dumb. It is often associated with the claim that the Nazis used fluoridated water supplies in their concentration camps to distract the inmates. Some will even claim that this is the purpose for fluoridation in the US!

I haven’t dealt with this particular myth yet, but really can’t do better than repeat this post from the US Life is Better with Teeth web site. (By the way, this is an excellent source of information on the fluoridation issue). The article is Fluoride and IQs

In July 2012, anti-fluoride activists circulated an article from a journal called Environmental Health Perspectives (EHP) to support their claim that fluoride lowers IQ scores in children. There are several reasons why the claim being made by opponents lacks credibility.

  • The EHP article reviewed studies on IQ scores for children living in areas of China, Mongolia and Iran where the water supplies have unusually high, natural fluoride levels. In many cases, the high-fluoride areas were significantly higher than the levels used to fluoridate public water systems in the U.S. In fact, the high-fluoride areas in these countries reached levels as high as 11.5 mg/L — more than 10 times higher than the optimal level used in the U.S.
  • This article offers a meta-analysis, and its credibility hinges on whether good-quality studies are reviewed. Yet the article’s co-authors admit that “each of the [studies] reviewed had deficiencies, in some cases rather serious, which limit the conclusions that can be drawn.” Although the studies compared high-fluoride with low-fluoride areas, the authors acknowledge that “the actual exposures of the individual children are not known.”
  • The two Harvard researchers who reviewed these studies have distanced themselves from the way in which anti-fluoride activists have misrepresented their article. After contacting these researchers, the Wichita Eagle newspaper reported, “While the studies the Harvard team reviewed did indicate that very high levels of fluoride could be linked to lower IQs among schoolchildren, the data is not particularly applicable here because it came from foreign sources where fluoride levels are multiple times higher than they are in American tap water.”
  • The Harvard researchers wrote in their article that the average standardized mean difference (0.45) in IQ scores “may be within the measurement error of IQ testing.” Despite web pages claiming that the article ”confirms” that fluoride reduces IQ scores, the Harvard co-authors did not reach a firm conclusion, writing instead that “our results support the possibility of adverse effects …” Indeed, their article called for more and better-quality research, including more “precise” data on the children involved and assurances that other factors have been ruled out as reasons for the IQ differences.
  • Given the small difference in IQ scores, it’s possible that arsenic levels, school quality, nutrition, parents’ educational levels or other factors could have shaped the results. The authors also added that “reports of lead concentrations in the study villages in China were not available”— another factor that could not be ruled out. A Britishresearch team reviewed similar Chinese studies, found “basic errors” in them, and reported that “water supplies may be contaminated with other chemicals such as arsenic, which may affect IQ.”
  • Between the 1940s and the 1990s, the average IQ scores of Americans improved 15 points.  This gain (approximately 3 IQ points per decade) came during the same period when fluoridation steadily expanded to serve millions and millions of additional Americans.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

Now I’m to blame for Stalin!

The Stalin terror was an argument used against communism or socialism but now it’s atheists who are getting the blame. To an extent this is a reaction by some Christians to the recognised role of religion in modern terrorism (especially Maoafter the September 2001 terrorist attacks in the USA). Maybe its also a Christian reaction to recent atheist writings on this. I can’t help thinking, though, that the motivation behind this blame is the old religious argument that one cannot be moral without religion and a new attempt to demonise atheists.

Some of the atheist writing on the role of religion in terrorism need criticism (see my post Sources of evil?). However, I want to deal with arguments about Stalin and Mao Zedong here because, though inappropriate, these arguments are getting some traction.

In a sense, the crimes of Stalin, Mao and the Christian Inquisition are problems for all of us.

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Sources of evil?

Since September 2001 we have become more aware of how religious belief can promote evil deeds. This is not new, however. The history of evil perpetrated in the name of religion has been discussed by authors such as Richard Dawkins (The God Delusion), Christopher Hitchens (God Is Not Great), Sam Harris (The End of Faith and Letter to a Christian Nation) and Michael Jordan (In the Name of God : Violence and Destruction in the World’s Religions).

One would have to be blind to disagree with these authors. However, I think the problem of their analyses is that it is restricted to considering only religion. This doesn’t help us understand the origins of evil in secular situations or evil activity carried out by mankind in general.

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