Category Archives: Science and Society

Connett & Hirzy do a shonky risk assesment for fluoride

Paul Connett, executive director of the Fluoridation Action Network (FAN), told me, during our fluoride debate, that he was writing a scientific paper defining a lower safety limit for fluoride than currently accepted. Nothing has been published yet – although a recent FAN newsletter did refer to a risk assessment paper by him and Bill Hirzy currently under review. I look forward to reading this paper, but I am not holding my breath as neither author has an impressive publication record.

Connett described his risk assessment for fluoride in the debate (see Fluoride debate: Paul Connett’s Closing statement) and he and Hirzy have also made comments on this lately. They are rejecting the current risk assessment, based on the incidence of severe dental fluorosis, and using the incidence of IQ deficits instead. To this end, they are heavily promoting the work of Choi et al., (2012) and Xiang et al., (2003) (which reported IQ deficits in areas where fluorosis is endemic). They are also attempting to rubbish published research (such as Broadbent et al., 2014) which show no significant IQ deficits at fluoride concentrations used in community water fluoridation.

Connett and Hirzy have also organised campaigns to congressional representatives in their effort to force a downward revision of the Environmental Protection Agency’s (EPA) standards for fluoridation.

Connett’s approach is a desk study – these guys are not going  to dirty their hands by doing their own research to get useful data. They are taking a value which they claim represent the lowest concentration of fluoride in drinking water below which no IQ deficit was found. They then apply “safety factors” to effectively conclude the only safe concentration is zero (see Scientist says EPA safe water fluoride levels must be zero)!

I will be a bit surprised if they manage to squeeze their paper though a decent review process because their approach is shonky. Look at the way they use the data from Xiang et al., (2003). (I have used the presentations by Connett and Hirzy at last February’s Sydney anti-fluoride conference as sources here). As I pointed out in Connett fiddles the data on fluoride, this data actually does not show a strong relationship between IQ and fluoride. The figure (from Xiang et al., 2003) shows the relationship between IQ and urinary fluoride and, in this case, the fluoride explains only about 3% of the variance in IQ.

Despite being statistically significant (p=0.003) this is certainly not evidence for a causative relationship. Clearly other, unconsidered, factors contribute to the variance and if these were considered the relationship with fluoride may be non-significant.

(Readers may notice the figure uses data for urinary not drinking water fluoride. Unfortunately, Xiang did not give a similar figure for fluoride concentration in drinking water. I have contacted him requesting the similar data for drinking water but so far have not had a meaningful response. Xiang did report drinking water fluoride is well correlated with urine fluoride so the above figure probably gives a good idea of the variability in drinking water fluoride as well).

Connett and Hirzy effectively ignore the high variability in the data and rely on a trick to get this  second graph. By splitting the concentration range into groups and taking the mean IQ for each group they make the situation look a lot more respectable. Who would guess from this trick that fluoride only explained about 3% of the IQ variance?

Connett illustrates his next step with this slide.

Sydney-Feb-21-key-step

He then claims that IQ deficits occur at a fluoride concentration of 1.26 ppm – he appears to have simply subtracted the value of one standard deviation from the mean of the lowest concentration group associated with a significantly different mean IQ to that of Xiang’s “control” group – Xinhaui village. That is strange because surely the first figure indicates  that low IQ values occur even for children with very low urinary fluoride, and most probably drinking water fluoride.

Connett then uses a safety factor of 10 (“to account for the wide range of sensitivity expected for any toxic substance in a large population”). Of course, this produces a maximum “safe” concentration of 0.13 ppm – which rules out all fluoridated water – and most natural water sources!

Sydney Feb 21 B Australia,  2015Connett goes on to promise his offsider, Bill Hirzy, will elaborate on the method they issued. Hirzy’s presentation did mention fluoride intake from other sources besides water. He then presents his conclusion on what the “safe daily dose” is fluoride – but no explanation of why! All the preceding slides in his presentation where self-justifying descriptions of his qualifications, employment history and how great his organisation, FAN, is.

IQ-Risk-Assessment-02.26.15

Conclusions

Connett and Hirzy are claiming IQ deficits are more important than dental fluorosis for setting of maximum fluoridation levels in drinking water. They are campaigning to get this accepted by legislators and the EPA.

Connett has been promising publication in a scientific journal for several years and recently implied that a paper is under review. If their publication efforts are successful a more critical assessment of their approach will be possible.

Available information indicates Connett and Hirzy have no original data but are relying on data from a study of children in an area of endemic fluorosis in China. They are refusing to accept published information from areas where community water fluoridation exists.

Their analysis also appears to rely on a tricky processing of the data to obscure the fact that fluoride probably only explains about 3% of the variance in IQ measured by the Chinese researchers! Legislators and policy makers would be foolish indeed to make changes to fluoridation standards on the basis of such data and poor analysis.

I could, of course, be wrong so eagerly await the Connett & Hirzy (2016?) paper.

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Making mountains out of scientific mole hills

Horton

Richard Horton, Editor of the Lancet speaking at the Global Health Metrics & Evaluation conference 2011. (Photo credit: Vimeo.)

The controversial Lancet editor, Richard Horton, has produced an opinion piece which some are interpreting as an attack on medical science, if not science in general. His article, What is medicine’s 5 sigma?, is being touted by websites like Collective Evolution as authoritative “evidence,” or justification, for their attempts to manufacture doubt on scientific issues (see Editor In Chief Of World’s Best Known Medical Journal: Half Of All The Literature Is False). And, of course, these messages are spread far and wide in social media like Facebook and Twitter by activists for various anti-science causes.

Horton, of course, exaggerates. He calls a spade a shovel – or even a giant earth moving machine. That is music to the ears of propagandists and manufacturers of doubt in the anti-vaccination, anti-fluoridation or even climate change denial movements. But, putting aside the damage such exaggeration causes for a moment, I do sympathise with some of Horton’s claims.

Provisional nature fo scientific knowledge

Horton begins with the statement “A lot of what is published is incorrect.”

While he appears to think this claim has shock value it is hardly news to scientific researchers. By its very nature, scientific knowledge is both provisional and incomplete. In the real world, no scientific idea or theory can accord completely with the true objective reality. We are always dealing with just a part of that reality. And our theories are always being replaced by new, updated and more complete theories which give better explanations of reality.  Let’s be clear, though, in most cases this is not a simple mechanical replacement but usually a modification to, or improvement of, existing theories.

So, yes, published science is “incorrect” in that it is always incomplete and provisional. It is always open to sceptical consideration and improvement – or even rejection.

However, Horton has really brought in the earth-moving machinery when he advances “the idea that something has gone fundamentally wrong with one of our greatest human creations.” 

Modern science is indeed “one of our greatest human creations” – despite the fact that it is by its very nature incomplete and imperfect.  Despite all the human problems influencing science it has still enabled us to solve many problems, to provide a more comfortable and safer existence for much of the world’s population and provided us with amazing technology (which critics of science enthusiastically use without being aware of the irony involved).

Sure, we still have many pressing problems to solve but no-one can seriously believe that science cannot contribute to the solution of these problems. In the end, despite all the human frailties inherent in such human endeavours, no other approach to obtaining knowledge and solving problems can seriously compete with science.

Some real problems

Horton gets specific:

“The case against science is straightforward: much of the scientific literature, perhaps half, may simply be untrue. Afflicted by studies with small sample sizes, tiny effects, invalid exploratory analyses, and flagrant conflicts of interest, together with an obsession for pursuing fashionable trends of dubious importance, science has taken a turn towards darkness.”

He also refers to those papers relying on correlations without showing causation, saying:

“Our love of “significance” pollutes the literature with many a statistical fairy-tale.”

But these problems are, in essence, not new and do not justify his purple prose about “a turn towards darkness.” That prose is rather hypocritical considering his own role in the publication of, and resistance to the retraction of, Andrew Wakefield’s article claiming a causal link between standard childhood vaccinations (measles, mumps and rubella) and autism (see  Why Is Richard Horton Still The Editor Of The Lancet?).

The fact is that poor quality research does get published – even by reputable journals like The Lancet (see for example Repeating bad science on fluoride). Poor quality research is not always knocked back, or improved, by the peer review processes journals use. These peer review processes themselves can be very flawed and even suffer from cronyism (see Poor peer review – and its consequences) and Poor peer-review – a case study) .

Many studies are poorly designed, report tiny effects and use small sample sizes. Many rely on statistically significant correlations which may be meaningless without any evidence for causation. Peer reviewers and journal editors, if they are actually conscientiously doing their jobs, are forced to make judgment calls. There is an argument for sometimes getting such studies into the literature where they can be critically examined and discussed. (Horton himself justified his decision to publish Andrew Wakefield’s article, which he acknowledged was an inferior study by claiming it would generate debate on the autism/vaccine issue).

But this backfires when uncritical journalists report the studies as scientifically credible, even gospel truth, when they are far from it. This is compounded by propagandists for activist groups who, confirmation bias in full flight, latch on to such studies to give “scientific authenticity” to their unscientific claims. And then promote them far and wide.

Recently we saw this with published papers claiming a link between fluoridation and thyroid problems (Peckham et al., 2015 – see Paper claiming water fluoridation linked to hypothyroidism slammed by experts) and ADHD (Malin and Till, 2015 – see ADHD linked to elevation not fluoridation). These papers were prime examples of Horton’s “statistical fairy tales.”

Reader beware

So, I am repeating a theme I often promote here. When it comes to the scientific literature it really is a matter of “reader beware.”

The reader must approach this literature carefully – intelligently and critically. The reader has the task of identifying “statistical fairy tales,” poor study designs and problems of tiny effects or small sample sizes. If the reader does not have the ability to do so they need to seek the opinions of qualified experts – and I don’t mean the self-appointed “world experts” leading activists groups or the google-informed commenters who seem to dominate social media and the internet.

After all, it is the real expert, many of whom are active researchers, who critically assess the scientific literature on a daily basis. And if they are participants in an active scientific community problems of confirmation bias are reduced.

The “reader beware” approach is even more necessary with the “scientific” claims often bandied about in the popular news media – mainstream media and especially the ideologically motivated “alternative” media.

I am an avid reader of the NZ Listener – which I consider a reputable mainstream journal. But every week I am annoyed by the small snippets reporting some new scientific claim (usually related to popular health issues) relying on individual scientific papers which I would place in Horton’s group of “statistical fairy tales.” I hope most readers are intelligent enough to seek further advice before taking such reports seriously.

But this annoyance is minor compared with what I feel about the rubbish I see daily on the internet daily. Ideologically motivated activists dominate social media here. They opportunistically link to such media reports, and even the original scientific papers, to give “scientific justification,” and confirmation bias for their unscientific messages.

When it comes to the internet one cannot repeat often enough – reader beware.

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Don’t expect to see chemical safety data sheets in restaurants

I keep coming across this very naive form of chemophobic scare-mongering – the use of safety data sheets to frighten consumers about trace chemicals in their environment, food and drink.

Here is an example anti-fluoridation propagandists continually use – safety data sheets for fluoridation chemicals like fluorosilicic acid. Often these people simply reproduce the image without comment – thinking this somehow proves their argument!

data sheets

I have discussed this issue for water treatment chemicals before (see Water treatment chemicals – why pick on fluoride?).

First, we need to be clear – Safety Data Sheets (or Material Safety Data Sheets) are not relevant to the chemicals we come across in our food drink – at the concentration they exist in these foods or drink. The safety data sheets are there for the use of those workers who must handle, transport  and dispose of concentrated chemicals. As Wikipedia explains:

“A SDS [Safety Data Sheet] for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting.”

In the article I link to above I give information, including that from safety data sheets, for the range of chemicals used in water treatment. Chemicals like Aluminium sulphate or alum, used as a flocculation and coagulation agent and chlorine which is used as a disinfection agent (here is the safety data sheet for chlorine).

The safety data sheets for these chemicals can be just as scary as for fluorosilicic acid. Even scarier for chlorine, which was used as a chemical weapon in the first world war. And the information is important for the people handling the concentrated chemicals, manufacturing them, transporting them and disposing of them to waste where necessary.

truck

Safety data sheets are important for people transporting concentrated chemicals.

But these sheets are completely irrelevant to people interested in the safety and nutritional value of their food which do not contain such concentrated chemicals (except for water, of course).

1378728302_Food-and-Drink-3

Safety data sheets are irrelevant to consumers of food and drink –  don’t expect your waiting staff to provide them in a restaurant.

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Being open-minded

This meme is for those commenters here who accuse me of having a closed mind.

open minded

I am always happy to change my opinion or view of things – if there is evidence to suggest I should.

And no, claims that “science once thought the world was flat,” or “science once supported smoking,” is not a credible argument that we should ignore current scientific consensus. It’s especially not an argument we should suddenly adopted unsupported claims as “gospel truth.”

Along these same lines, it’s worth considering this quote from Carl Sagan – if you want me to consider a really extraordinary claim your evidence had better be exceptional.

extra

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RSNZ Science Book Prize winner – Tangata Whenua

Tangata Whenua: an Illustrated History won the Royal Society of NZ Science 2015 book prize. It is written by Atholl Anderson, the late Dame Judith Binney and Aroha Harris and published by Bridget Williams Books. The book charts the sweep of Māori history from ancient origins through to the twenty-first century.

In announcing this result on Friday Dr Andrew Cleland, Chief Executive of the Royal Society of New Zealand, noted that Tangata Whenua incorporates research from a range of disciplines from the sciences, including social science, and the humanities, which mirrors the breadth of scholarship supported by the Society.

In addition to being a history, the book is based on research on genetics and climate science as well as:

  • archaeology (the study of past human activity through material left behind by human populations)
  • anthropology (study of human society)
  • ethnography (study of culture)
  • paleoecology (study of past ecosystems or environments, reconstructed from fossils).

The other books shortlisted for the 2015 Royal Society of New Zealand Book Prize were:

  • The Wandering Mind by Michael Corballis (Auckland University Press)
  • Gathering Evidence by Caoilinn Hughes (Victoria University Press)
  • Dolphins of Aotearoa: Living with New Zealand Dolphins by Raewyn Peart (Craig Potton Publishing)
  • Manuka: the Biography of an Extraordinary Honey by Cliff Van Eaton (Exisle Publishing)

You can buy your own copy from Whitcoulls for $99.99.

See also:

New Zealand science book prize – 2015 Short list
The Long Journey to Aotearoa – Veronika Meduna, Radio NZ, talks to Atholl Anderson

The problem of “Fact-Resistant Humans”

Borowitz-Earth-Endangered-by-Fact-Resistant-Humans-1200

OK, this is satire so don’t take it literally. But this article in The New Yorker makes a good point – Scientists: Earth Endangered by New Strain of Fact-Resistant Humans.


MINNEAPOLIS (The Borowitz Report) – Scientists have discovered a powerful new strain of fact-resistant humans who are threatening the ability of Earth to sustain life, a sobering new study reports.

The research, conducted by the University of Minnesota, identifies a virulent strain of humans who are virtually immune to any form of verifiable knowledge, leaving scientists at a loss as to how to combat them.

“These humans appear to have all the faculties necessary to receive and process information,” Davis Logsdon, one of the scientists who contributed to the study, said. “And yet, somehow, they have developed defenses that, for all intents and purposes, have rendered those faculties totally inactive.”

More worryingly, Logsdon said, “As facts have multiplied, their defenses against those facts have only grown more powerful.”

While scientists have no clear understanding of the mechanisms that prevent the fact-resistant humans from absorbing data, they theorize that the strain may have developed the ability to intercept and discard information en route from the auditory nerve to the brain. “The normal functions of human consciousness have been completely nullified,” Logsdon said.

While reaffirming the gloomy assessments of the study, Logsdon held out hope that the threat of fact-resistant humans could be mitigated in the future. “Our research is very preliminary, but it’s possible that they will become more receptive to facts once they are in an environment without food, water, or oxygen,” he said.

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Water fluoridation effective – new study

A recent Australian study shows community water fluoridation (CWF)  has a beneficial effect on oral health, even after taking into account the known effects of socioeconomic status and sugar consumption.

This is important because anti-fluoride propagandists are always pushing the mistaken claim that CWF is based only on “old science” and that “the science establishment” refuses to check these old findings. These propagandists have also latched onto the concern over the effects of excessive sugar consumption on general and oral health to claim that any apparent beneficial effect of CWF would disappear if sugar consumption was reduced.

The study is reported in:

Blinkhorn, A. S., Byun, R., Mehta, P., & Kay, M. (2015). A 4-year assessment of a new water-fluoridation scheme in New South Wales, Australia. International Dental Journal.

It  followed changes in the dental health of children in Gosford City, NSW, after introduction of CWF in 2008. It compared this with the oral health of children living in areas that had been fluoridated for over 40 years, and with those in the Shires of Ballina and Byron which were unfluoridated and had no plans to introduce CWF.

CWF clearly beneficial

The figure below compares the average numbers of decayed, missing and filled teeth (dmft) of 5-7 year-old children in 2008 (just before introduction of CWF to Gosford city – the “newly fluoridated area) with new batches of 5-7 year-old children in 2010 and 2012. In all three periods comparisons were made to similar children in the unfluoridated and long-term fluoridated areas.

dmft-aus1

Of course, anti-fluoridation activists might pick up on the improved oral health of children in unfluoridated areas in 2012 (and they might even try to ignore the rest of the data). But the clear message is that even though there may be a general improvement in oral health over time the children in the fluoridated areas still showed a clear benefit.

Influence of other factors

This study included measurement of other factors known to influence oral health. Statistical analysis of the data showed poorer dental health was significantly related to:

  • lower socioeconomic status;
  • origins (poorer dental health when mothers were born in a non-English speaking country;
  • lower educational level attained by parents, and
  • sugary drink consumption (poorer dental health where children consumed one or more drinks a day).

But, importantly, the statistical analysis showed a significant beneficial influence of CWF after taking these other factors into account. The following graph compares the dmft for newly fluoridated and unfluoridated areas relative to long-term fluoridated areas (defined as 1.0)

dmft-aus2

We can see that by 2012, 4 years after introduction of CWF, there is no significant difference between the oral health of children in the long-term and newly fluoridated areas. However, the oral health of children in the unfluoridated areas was significant poorer at all times.

Conclusion

Origins, socioeconomic status and consumption of sugary drinks have a statistically significant effect on children’s oral health. However, even when these are taken into account this research shows a clear beneficial effect of CWF on children’s dental health.

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Follow the money?

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The distrust of science – a task for science communication

Michael Foley

Michael Foley, a Senior Lecturer in Public health dentistry at The University of Queensland has an interesting  article in The Conversation* – ‘Holistic’ dentistry: more poppycock than panacea?

He declares that “all dentists should be practicing holistic medicine.” After all, the World health Organisation’s definition of health (“a complete state of physical, mental and social well-being, and not merely the absence of disease or infirmity”) “sits very well with the concept of holistic dentistry”

But, as Foley says, dentists “should all be practising evidence-based dentistry, too.”

And there is the problem. A perfectly legitimate term has been hijacked in an effort to misinform possible clients. An internet search shows most Australian holistic dentists also endorse and encourage alternative therapies like:

homeopathy, naturopathy, Bach flower essences, acupuncture, traditional Chinese medicine, chiropractic, ayurvedic medicine, osteopathy, kinesiology, crystals, aromatherapy, reiki, vibrational healing, Buteyko and esoteric chakra-puncture.”

As he says, despite  his belief that “Most holistic dental practices will provide a wonderfully caring and nurturing environment for patients .. . . a patient-dentist relationship must also be based on trust and professionalism.”

The placebo effect is not enough and reliance on it could even be dangerous.

But alternative health practices like this do have a market – and for some people their appeal lies with their distrust of science.

Distrust of science and the power of consensus

Sander van der Linden and Stephan Lewandowsky discuss this distrust and how to combat it in a recent scientific American article – How to Combat Distrust of Science.

They centre their argument around the issue of climate science, but I think they are also relevant to alternative health and the distrust of health experts common in our society.

On the one hand they attribute difference in the acceptance of science to the way that people interpret the same information very differently.

“As psychologists, we are more than familiar with the finding that our brains selectively attend to, process and recall information. One consequence of this is “confirmation bias,” a strong tendency to automatically favor information that supports our prior expectations. When we consider issues that we feel strongly about (e.g., global warming), confirmation bias reaches a new height: it transitions into “motivated reasoning.” Motivated reasoning is the additional tendency to defensively reject information that contradicts deeply held worldviews and opinions. One example of this is the “motivated rejection of science”; if you are personally convinced that global warming is a hoax, you are likely to reject any scientific information to the contrary – regardless of its accuracy.”

A message for science communicators

That is an argument which could suggest that science communicators are “just blowing in the wind.”

On the other hand the authors argue that “expert consensus” can counter this.

“Our research shows that highlighting how many experts agree on a controversial issue has a far-reaching psychological influence. In particular, it has the surprising ability to “neutralize” polarizing worldviews and can lead to greater science acceptance.”

In their work they found that if people had been exposed to background material containing the message “97% of climate scientists have concluded that human-caused climate change is happening” they actually increased their estimate of scientific support for human-caused climate change by about 13% (and 20% in some cases). In later work they found a causal link between highlighting expert consensus and increased science acceptance.

This suggests to me that many people may take up an essentially anti-science stance because they are just unaware of the facts of consensus, or are under the illusion that scientific dissent is greater than the objective facts show.

I see that as a positive message. We often concentrate on the anti-science position of ideologically motivated people and forget that the majority are probably misinformed – both about the science and the degree of expert consensus. It is this majority, rather than the ideologically motivated science distrusters, who science communicators need to target.

Are we biologically wired to accept consensus?

The authors suggest there are good biological reasons for the positive effect of consensus information and the negative effect of dissent information on the acceptance of science.

“One feature that clearly distinguishes “consensus” from other types of information is its normative nature. That is, consensus is a powerful descriptive social fact: it tells us about the number of people who agree on important issues (i.e., the norm within a community). Humans evolved living in social groups and much psychological researchhas shown that people are particularly receptive to social information. Indeed, consensus decision-making is widespread in human and non-human animals. Because decision-strategies that require widespread agreement lie at the very basis of the evolution of human cooperation, people may be biologically wired to pay attention to consensus-data.”

That is also sensible:

” Imagine reading a road sign that informs you that 97% of engineers have concluded that the bridge in front of you is unsafe to cross. You would likely base your decision to cross or avoid that bridge on the expert consensus, irrespective of your personal convictions. Few people would get out of their car and spend the rest of the afternoon personally assessing the structural condition of the bridge (even if you were an expert).”

And practical:

” it makes perfect sense for people to use expert consensus as a decision-heuristic to guide their beliefs and behavior. Society has evolved to a point where we routinely defer to others for advice—from our family doctors to car mechanics; we rely on experts to keep our lives safe and productive. Most of us are constrained by limited time and resources and reliance on consensus efficiently reduces the cost of individual learning.”

The message, then, is:

“A recent study showed that people are more likely to cling onto their personal ideologies in the absence of “facts.” This suggests that in order to increase acceptance of science, we need more “facts.” We agree but suggest that this is particularly true for an underleveraged but psychologically powerful type of fact — expert consensus.”

The “merchants of doubt”

The ideologically and commercially motivated opponents of science recognise this – hence their attempts to sow doubt on the scientific consensus.

They will promote the message that there is no consensus. Or that the very fact of a consensus is somehow a “proof” the science is wrong because scientific understanding will change in the future (the Galileo gambit – see The Galileo fallacy and denigration of scientific consensus).

They will promote the message that the experts are frauds (eg Climategate) “shills” – in the pay of political or economic forces – Big Pharma, the fertiliser industry in the case of fluoridation, etc. Ironic, really, because these very anti-science propagandists are often themselves supported and/or financed by energy companies (in the case of climate change deniers) and “natural”/alternative health big business in the case of anti-fluoridation and anti-vaccination activists

So, perhaps another task for science communicators. propaganda claiming scientific fraud, unethical scientific funding, etc., needs to be countered. But also the public needs to be made aware of the commercial and ideological motivations of those who attempt to misrepresent the science and the expert consensus.


* The conversation has some excellent articles. But Christopher Pyne in his article Government funding for The Conversation website to be axed, reveals that government funding for it is to be stopped.

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Poor peer review – and its consequences

peer-review-diagram

See below for citations used

The diagram above displays links between the journal, editors and reviewers in the case of the paper Malin & Till (2015). I discussed these links before in Poor peer-review – a case study  but thought a diagram merited a separate post. “A picture is worth a thousand words,” they say.Unfortunately, I suspect, such incestuous arrangements around

Unfortunately, I suspect, such incestuous arrangements around the publication of a scientific paper is probably not too unusual. I guess it is human nature for authors to choose a journal which might be sympathetic (or biased) towards their ideas. In this case, the journal and its editors clearly have an orientation towards chemical toxicity hypotheses. The journal even allows authors to suggest possible referees. So again it is only human nature for the authors to suggest referees they consider sympathetic. Or perhaps it is only human nature for Grandjean or Bellinger to suggest referees they know are sympathetic to their own chemical toxicity hypotheses.

Human nature – but certainly not in the best interests of science – or the best outcome for the paper. The authors could have suggested at least some referees with experience in the field of attention deficit hyperactivity disorder (ADHD). And the editors could have done the same. This way they could have produced a better outcome – proper revision of the paper to consider other factors besides chemical toxicity. Or even the withdrawal of the paper itself once everyone realised that their fluoride toxicity hypothesis didn’t stand up to proper testing.

Just imagine if referees like the seven authors of Huber et al (2015) had been considered. I discussed their paper in ADHD link to fluoridation claim undermined again. It considered the same ADHD data as Malin & Till (2015) but found other, non-chemical factors, were implicated. In particular they found a correlation with altitude.  If a referee of the Malin & Till (2015) paper had suggested they consider factors like altitude the Malin & Till (2015) may never have seen the light of day. It would have, at least, been heavily modified.

And we would not have anti-fluoride activists and “natural”/alternative health web pages and magazines promoting the myth that community water fluoridation causes ADHD.

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Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368.

Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2015). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101.

Grandjean, P., & Landrigan, P. J. (2014). Neurobehavioural effects of developmental toxicity. Lancet Neurol, 13(March), 330–338.

Huber, R. S., Kim, T.-S., Kim, N., Kuykendall, M. D., Sherwood, S. N., Renshaw, P. F., & Kondo, D. G. (2015). Association Between Altitude and Regional Variation of ADHD in Youth. Journal of Attention Disorders.

Malin, A. J., & Till, C. (2015). Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association. Environmental Health, 14.