Category Archives: science

A week of good news in New Zealand

It’s been a week for good news in New Zealand. Well, most people see the news as good.

The first good news was the Prime Minister’s announcement a few days ago that she is expecting a child. Great news for her and her partner, as she had expected that assisted fertility treatments would have been required. Also, the news seems to have been enthusiastically welcomed by most New Zealanders – even her political opponents – on the whole. It is hard to tell if the few negative voices are die-hard anti-labour people still annoyed at the September election result. Or died in the wool misogynists who do not understand the role women play today in our society.

Today we had news of New Zealand’s first successful launch of satellites into space. The launch was carried out by Rocket Lab at their launch site in the Māhia Peninsula.

Quite exciting to follow a launch like this and hear the updates in Kiwi accents!

The Video above is a little over 30 minutes long – but, if you want to watch the actual launch, fast forward to about 18 minutes.

The rocket carried three satellite into orbit. Professor Richard Easther from Auckland University  said the launch represented a “red-letter day for New Zealand:”

“To put this into perspective, we are now one of just a dozen countries to have successfully built and deployed a rocket that can put satellites into orbit.”

The other nations are either world powers such as the USA and Russia, or smaller countries “which are armed to the teeth” such as Israel and North Korea.

According to Easther  – “New Zealand really stands alone with a technically advanced, commercially focused launch vehicle.”

He added it was “just the first chapter in what promises to be a fascinating story for the country and our technology and science sectors.”

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Confirmation bias – we all suffer from it but how can we reduce its effect?

Confirmation bias – we all suffer from it. It’s just part of being human. Sure, we are capable of rational thought but it is often overridden by our emotional messages. And even in the best situations, our attempt at rational thought is inevitably contaminated by our emotions.

This video from Above the Noise • PBS explains what is going on in a popular way. Even resorts to brain scans.

Word of warning, though. It inevitably suffers from its own confirmation bias. Right up front, it produces a graph comparing Facebook clicks on “fake news” articles compared with clicks on “mainstream news” articles!! As if that is a proper analysis.

We all know mainstream media regularly publishes fake news. What they are probably comparing is Facebook clicks for mainstream media articles compared with alternative media articles. That is just not an intelligent differentiation when talking about “fake news.”

So take the video with a grain of salt.  Look at it critically and intelligently.

In fact, probably the best way of avoiding, or at least reducing confirmation bias is to approach all information, from whatever source, critically and intelligently. To think for oneself. Avoid group thinking and official interpretations.

Anti-fluoridationists misrepresent New Zealand dental data – an annual event

Caught again! – NZ anti-fluoride campaigners tell their annual porky about the MoH statistics for the dental health of school children.

This exercise in confirmation bias by New Zealand anti-fluoridation campaigners has become an annual tradition involving confirmation bias and cherry-picking. Every year the Ministry of Health (MoH) releases a spreadsheet containing the most recent data on school children’s dental health. And every year the Fluoride Free NZ (FFNZ) activists select some figures from the spreadsheet to argue their case that fluoridation is not effective. A simple exercise in bias confirmation by cherry picking.

I wrote about last year’s exercise in my article Anti-fluoridationists misrepresent new dental data for New Zealand children. That involved the MoH data for 2015. My comments on their misrepresentation of the newly released 2016 data will be much the same.

FFNZ claims the 2016 statistics:

“show absolutely NO difference in dental decay rates between five year olds in fluoridated areas compared to non-fluoridated areas.”

Notice the specifics – 5-year-olds. And no mention of ethnicity. They have simply used the total figures (which mislead because of effects of ethnic differences) and cherry-picked the specific data where the figure for fluoridated areas and non-fluoridated areas are very close.

What does the new data really say?

Let’s look at a summary of the data – for 5-year-olds and year 8 children – and for the different ethnic groups listed – Māori, Pacific Island and “other”(mainly Pakeha and Asian).  You can download the spreadsheets contain the data from the MoH web page – Age 5 and Year 8 oral health data from the Community Oral Health ServiceWe will look at the % of these children that a free from caries as well as the mean decayed, missing and filled teeth (dmft and DMFT) for each group.

5-year-olds

Notice the FFNZ cherry picking? Yes, the “Total” figures show very little difference but if they had dared look at different ethnic groups their argument would not have looked so great. Fluoridation appears to be associated with an improvement of dental health from about 6% (for “Other”) to 23% (for Māori)

Year 8 children

You can see why  FFNZ chose the 5-year-olds instead of year 8 children. Even the misleading data for the “Total” group suggests an almost 20% improvement of dental health in fluoridated areas.  Fluoridation appears to be associated with an improvement of dental health from about 18% (for “Other”) to 30% (for Māori)

Importance of ethnic classifications.

The figures above show big differences between ethnic groups, with the dental health of Pacific Island children being the worst.

This is an important factor because most Pacific Island children live in fluoridated areas – about 85%. The figure below shows the distribution of the two different age groups.

This means that the overall, or “Total” data is distorted. Pacific Island children predominance in fluoridated areas increase the value of dmft/DMFT and lowers the value of caries-free % in the fluoridated areas.

So the FFNZ activists are not only cherry picking to confirm a bias – they have selected the figures which are most distorted by ethnic differences.

Far from the latest data showing “absolutely NO difference” it actually shows differences of the order of 18 -30%.

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Fluoridation means money in the pocket

Local researchers recently presented data showing that the ordinary person, and not the taxation financed health system, is the main financial beneficiary of community water fluoridation.

Their research confirmed that community water fluoridation in New Zealand is highly cost-effective for all but the smallest communities. This study updates previous evaluations by including data for adults – previous studies were limited to children. It also corrected for under-estimation of averted dental restoration costs in a previous study.

The authors also make the point that an update is necessary because:

“Sound public health practice requires periodic re-evaluation of interventions’ benefits and costs.”

The results are reported in the paper:

Moore, D., Poynton, M., Broadbent, J. M., & Thomson, W. M. (2017). The costs and benefits of water fluoridation in NZ. BMC Oral Health, 17(1), 134.

Community size

As with previous studies, the results confirmed that fluoridation is not cost effective for very small communities because of the capital cost of fluoridation plants and the use of sodium fluoride instead of fluorosilicic acid as the fluoridating chemical in small plants. However:

“For ‘minor’ through to ‘large’ plants, there is a net cost saving. For a ‘large’ plant supplying 50,000 people, the cost offsets are over 20 times the cost of fluoridation. The break-even point appears to be reached by ‘minor’ plants supplying a population over 500.”

National net savings from universal fluoridation

The authours estimated the national costs and saving from averted ental costs over a 20 year period. If all New Zealand reticulated water supplies serving populations greater than 500 were fluoridated costs over 20 years would amount to$177 million while the cost offset due to averted dental treatment costs would be $1578 million.

The national 20-year net saving due to such universal community water fluoridation in NZ would amount to $1401 million.

That is a nine times pay-off!

Individuals save more than the state

I hadn’t thought of this before but the data enables separate estimates of savings to the state from universal CWF through reduced costs to the health budget, and to the individual citizen through their reduced costs for private dental treatment.

In fact, the major benefit is to the individual rather than the health budget.  National savings over 20 years for reduction of private dental care expenditure would be $1428 million – 10 times the savings to the national health budget.

Perhaps this helps people understand that they, personally, have something to gain fiancially from community water fluoridation

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Anti-fluoridation campaigners often use statistical significance to confirm bias

I was pleased to read this Nature article – Five ways to fix statistics – recently as it mirrors my concern at the way statistical analysis is sometimes used to justify or confirm a bias and not reveal a real causal relationship. Frankly these days I just get turned off by media reports of studies showing statistically significant relationships as evidence for or against the latest health or other fads.

As the Nature article says, statistical significance tests often amount “to uncertainty laundering:”

“Any study, no matter how poorly designed and conducted, can lead to statistical significance and thus a declaration of truth or falsity. NHST [null hypothesis significance testing] was supposed to protect researchers from over-interpreting noisy data. Now it has the opposite effect.”

No matter how good a relationship appears, or how significant the statistical analysis shows it to be, it is simply a relationship and may have no mechanistic or causal backing.  An example often used to illustrate this is the close relationship between the prevalence of autism and sales of organic produce.

Clearly statically significant but we don’t find those activists claiming autism is related to one thing or another ever citing this one. I am picking these activists may well have a bias towards organic produce.

Here are several examples I have discussed before which illustrates how “statistical significance” is sometimes used to confirm bias in fluoridation studies. I think these are very relevant as anti-fluoridation campaigners often cite statistical significance as if it is the final proof for their claims.

Ignoring relevant confounders

This is an easy trap for the biased researcher (and let’s face it, most of us are biased – it’s only human). Just ignore other confounders or risk-modifying factors that may be more important. Or ignore the fact that the risk-modifying factor one is interested in (in this case fluoride) may just be acting as a proxy for (and therefore is related to) something else which is more relevant.

This why all credible risk-modifying factors should be considered in correlation studies. They should be included in the statistical analyses.

It’s amazing how many researchers either ignore the possible risk-modifying factors besides their pet one – or pay lip-service to the problem by limiting their consideration to only a small range of such factors.

Examples of studies promoted by anti-fluoride campaigners where this is a problem include:

Peckham et al., (2015) hypothyroidism paper:

Peckham, S., Lowery, D., & Spencer, S. (2015). Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water. J Epidemiol Community Health, 1–6.

This has been widely condemned for a number of reasons – one of which is that iodine deficiency, a known factor in hypothyroidism, was not included in the statistical analysis.

(See Paper claiming water fluoridation linked to hypothyroidism slammed by experts and Anti-fluoride hypothyroidism paper slammed yet again).

The  Takahashi et al., (2001) cancer paper:

Takahashi, K., Akiniwa, K., & Narita, K. (2001). Regression Analysis of Cancer Rates and Water Fluoride in the USA based Incidence on IACR / IARC ( WHO ) Data ( 1978-1992 ). Journal of Epidemiology, 11(4), 170–179.

These authors reported an association between fluoridation and a range of cancers. Problem is, they did not consider any other risk-modifying factors. When some geographical parameters were included in the statistical analyses there were no statistically significant relationships of cancer with fluoridation.

(see Fluoridation and cancer).

The Malin & Till (2015) ADHD paper:

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.

This reported an association of ADHD prevalence with the extent of fluoridation in the US. Anti-fluoride campaigners have cited this paper a lot because it is the only study indicating any effect of fluoridation on cognitive ability. All other studies they rely on were from areas of endemic fluorosis where the natural levels of fluoride are higher than that used in community water fluoridation.

Malin & Till (2015) considered only household income as a possible risk-modifying factor. No consideration was given to residential elevation which other researchers had around the same time reported as associated with ADHD prevalence.

I repeated their statistical analysis but included residential elevation and a range of other risk-modifying factors. This showed there was no statically signficant association of ADHD with fluoridation when other risk-modifying factors, particularly elevation, were included. My critique of Malin and Till (20215) is now published:

Perrott, K. W. (2017). Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till ( 2015 ). Br Dent J.

(See ADHD linked to elevation not fluoridationADHD link to fluoridation claim undermined again and Fluoridation not associated with ADHD – a myth put to rest).

Ignoring the lack of explanatory power

I think this is where the over-reliance on statistical significance, the p-value, can be really misleading. Researchers desperately wishing to confirm their bias will proudly claim  a statistically significant relationship, a p-value less than 0.05, etc., as if that is the final “proof.” These researchers will often hide the real meaning of their relationship by not making the actual data available or limiting their report of their statistical analysis to p-vlaues and, maybe, a mathematical relationship.

However, if the reported relationship actually explains only a small part of the observed variation in the data it may be meaningless. Concentration on such a relationship means that other more signficant risk-modifying factors which would explain more of the variation are ignored. Anyway, where a factor explains only a small part of the variation it is likely a more complete statistical analysis would show that its contribution was not actually statistically signficant.

Some examples:

The prenatal fluoride exposure and IQ study of Bashash et al (2017):

Bashash, M., Thomas, D., Hu, H., Martinez-mier, E. A., Sanchez, B. N., Basu, N., … Hernández-avila, M. (2016). Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6 – 12 Years of Age in Mexico.Environmental Health Perspectives, 1, 1–12.

These authors reported a statistically significant association of Child IQ with the prenatal fluoride exposure of their mothers. However, their figures showed a very wide scatter in the data indicating very little explanation of the variation in child IQ by the association with prenatal fluoride. (see below left). This must be why the Fluoride Action Network removed the data points from the figure when reproducing it for their promotion of the paper (see below right).

Bashash et al., (29017) did not give the complete statistical analysis of their data. However, I was able to digitally extract the data from their figure and my analysis showed that prenatal fluoride expose was only able to explain a little over 3% of the variation in child IQ. So, despite the statistical significance of their observed relationship prenatal fluoride exposure is unlikely to be a real factor in child IQ. In fact, concentration on this minor (even if statistically significant) factor will only inhibit the discovery of the real causes of IQ variation in these children.

Yes, anti-fluoride campaigners will protest that this study did consider some other possible risk-modifying factors. However the very low-level of explanation of the variation in the data indicates they did not consider enough.

(see Premature births a factor in cognitive deficits observed in areas of endemic fluorosis? Fluoride, pregnancy and the IQ of offspring and Maternal urinary fluoride/IQ study – an update).

The Xiang et al., (2003) water fluoride and IQ study:

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.

Anti-fluoride campaigners rely a lot on this and other papers from this group.  Even though this research involved areas of endemic fluorosis it, in a sense, provides some of their best evidence because they reported a dose-dependent relationship of IQ to water F. Xiang et al., (2003) claimed a statistically signficant association of child IQ to fluoride water levels.  Other anti-fluoride campaigners, and some other researchers, have cited Xiang et al., (2003) to support such an association.

I don’t question these researchers found a significant association – but there is a problem. Nowhere do they give a statistical analysis or the data to support their claim! Very frustrating for critical readers (and we should all be critical readers).

They did, however, give some evidence from a statical analysis of the relationship of IQ with urinary fluoride. They did not give a complete statistical analysis but they included the data in a figure  (see below) – so I did my own statistical analysis of data digitally extracted from the figure.

The figure shows a high scatter of data points so this is another case of a statistically significant relationship explaining only a small part of the variability. My analysis indicates the relationship explains only about 3% of the variability in IQ value. Another case where researchers have concentrated on their own pet relationship and in the process not properly searched for more reasonable risk-modifying factors capable of explaining a larger proportion of the variation.

I have made a more detailed critique of Xiang et al.  (2015) and Hirzy et al., (2016) which relies on this data (see Does drinking water fluoride influence IQ? A critique of Hirzy et al. (2016)). A paper based on this has been submitted to a journal for publication and is currently undergoing peer review..

(see Anti-fluoride authors indulge in data manipulation and statistical porkiesDebunking a “classic” fluoride-IQ paper by leading anti-fluoride propagandists,  Connett fiddles the data on fluorideConnett & Hirzy do a shonky risk assesment for fluoride and Connett misrepresents the fluoride and IQ data yet again).

Conclusion

This  briefly outlines the statistical problems of a number of papers anti-fluoride campaigners rely on. Two common problems are:

  • Insufficient consideration of confounders or other risk-modifying factors – indicating a bias towards a “preferred” cause, and
  • Reliance on a relationship that, although statistically significant, explains only a very small fraction of the observed variation – again indicating bias towards a “preferred” cause

I don’t for a minute suggest that only those researchers publishing “anti-fluoride” research are guilty of these errors. They are probably quite common. Authors will generally responsibly warn that “correlation does not prove causation” and suggest more work needs to be done including  consideration of a wider number of confounders or risk-modifying factors. However, bias is only human so researcher advocacy for their own findings is understandable. The published research may even be of general value if readers interpret it critically and intelligently.

However, in the political world such critical consideration is very rare. Activists will use published research in the way a drunk uses a lamppost – more for support than for illumination. This makes it important that the rest of us be more objective and critically assess the claims they are making. Part of this critical assessment must include an objective consideration of the published research that is being cited.

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The problem with scepticism

Some readers may be aware I am being purposely provocative with this logo as it identifies the problem of extending the sceptical approach into the political sphere – emotions of identity and values. Image credit: RT America YouTube.


Being a sceptic has its problems. On the one hand, a sceptical approach to information has never been more necessary. On the other hand labelling oneself a Sceptic (or Skeptic) can have negative results – encouraging arrogance and inability to accept criticism.

I have been thinking about this a lot lately and have again and again found myself encouraging a sceptical approach to everything we read – from whatever source. But I also found myself largely agreeing with a recent article in Patheos critical of sceptics by Matthew Facciani – Why Identifying As A Skeptic Can Be Problematic Then I attended (partially) the NZ Skeptics conference in Wellington last weekend – a great conference with some excellent presentations.

But something that struck me during the conference is that the scepticism was really limited to what Wikipedia defines as scientific  or empirical scepticism which questions “beliefs on the basis of scientific understanding:”

“Scientific skepticism may discard beliefs pertaining to purported phenomena not subject to reliable observation and thus not systematic or testable empirically. Most scientists, being scientific skeptics, test the reliability of certain kinds of claims by subjecting them to a systematic investigation using some type of the scientific methodAs a result, a number of claims are considered as “pseudoscience“, if they are found to improperly apply or ignore the fundamental aspects of the scientific method.”

I think this is far too limiting. Societies are faced with many issues – only some of them come under the scientific or empirical classification.

Scepticism needs to be applied more widely

I sometimes think our modern society has quite a good handle on scientific and empirical issues. Sure, we could improve the understanding of what science is and there are far too many people around who are imbued with anti-science or pseudoscience ideas.  But look at the political sphere – aren’t dogmatic and irrational ideas there more common than pseudoscientific ones? Don’t we suffer more from political “woo” than we do from “woo” in the scientific or health areas?

The general definition of scepticism given by Wikipedia in the same article is:

Skepticism (American English) or scepticism (British Englishsee spelling differences) is generally any questioning attitude or doubt towards one or more items of putative knowledge or belief.”

So here is my point – why do “Sceptics,” in practice, limit themselves in this way? Perhaps many “Sceptics” would deny they do – but time and again I come across people who adhere, or attempt to adhere, to a rational and evidence-based approach in matters of health and science (things like creationism, flat earth fanatics, acupuncturists, anti-fluoridationists and homoeopaths) yet will accept, even pontificate on, biased and tribal political arguments without any respect for evidence. Or will seek “evidence” for their political beliefs in a very partisan way. Quite different to their more objective approach on scientific and empirical issues.

My personal feeling is that this problem is inevitable. We are not a rational species, more a rationalising one. Humans definitely have the ability to pursue logical and rational thought but emotions still linger under the surface. Probably a good thing as this makes us human and not robots.

So “scientific or empirical sceptics” are able to follow the evidence and logic to a rational conclusion. Partly because they have not started with any emotional or values-based committment to the final conclusions. Although a non-Sceptic speaker at the Wellington conference did make the valid point that even sceptics will react emotionally when their rational conclusions are challenged by non-sceptics. That is because they inevitably do, in the end, feel an identity with those conclusions. They do so not because they fell an ideological committment to the conclusions – the commitment is to the method used to reach the conclusions.

We are all influenced by emotions and values

Even the most rational thinkers are influenced by emotions and valvalues. These may exert a bigger role when the sceptic has to deal with a subject outside their area of knowledge and they are therefore less secure in their understanding.  Or, perhaps more strongly, in areas like politics and religion where values and identity attachments are much stronger.

Perhaps this is why a Skeptics conference will deal only with the scientific or empirical subjects and not treat the political ones in the same manner. These may be avoided in fear they will lead to conflict. Or worse, they are avoided because of a prevailing political consensus. A consensus which may have no evidential or rational basis.

I really don’t like the way groups assume a consensus in this way. It is this assumption which has probably annoyed me most about the partisan-driven political hysteria in the US at the moment and the way this has been uncritically accepted here by people who, on the basis of their sceptical or rational approach on scientific issues, should know better.

Being sceptical of sceptics

In his Patheos article Matthew Facciani gives a general definition – “a skeptic is someone who tries to be objective and questions the validity of many things.”

I am certainly with him there as I really cannot understand why anyone should limit their sceptical approach to only an approved field. Matthew then goes on to say:

“I used to think of myself as a skeptic. It seems like a identifying with skepticism is a good trait to have. However, I’ve grown to really dislike the word over time and now feel rather skeptical of those who identify as skeptics!

I’ve run into far too many skeptics who turn off their skepticism when it’s convenient for them. You’ll see them apply great skepticism to some areas (like religion), but then become much less critical of ideas that are consistent with their own ideologies (like maintaining the status quo).”

I wonder if many New Zealand Sceptics (or Skeptics) have had the same experience? I certainly have and it is one reason why I would never join the NZ Skeptics Society. (To be accurate, that general reason is probably why I never join any societies – I really can’t adhere to a “Party line”).

Identity problems

Matthew explains this problem partly by identity theory:

“people are going to be motivated to ignore information that conflicts with their identity. So this becomes a problem when a conservative rejects evidence for climate change for example. Their deeply held beliefs are threatened with evidence that climate change is caused by human activity, so they are extra motivated to ignore it.

 So if you are a skeptic, a person who thinks as themselves as particularly objective and rational, wouldn’t it be threatening to be told you are being irrational? As someone who used to identify as a skeptic, I would say this was the case for me. The stronger the identity is held, the more vulnerable a person is to being biased. So if someone strongly thinks of themselves as an amazing skeptic, it may be very identity-threatening to be exposed to information that proves them wrong. Especially if that information threatens another identity they have!’
All very human of course. But it is a worry when someone who may have a well-founded objectivity and rationality about a scientific subject automatically transfers the resulting confidence to another area like politics where it simply works to support their biases and values and not facts.

The bias blind spot

Another issues he raises is the bias blind spot:
Worryingly, researchers report:
“that higher cognitive ability does not prevent people from experience this bias blind spot. In fact, those with high intelligence can even be better at rationalizing away their biases!”
As I keep saying, we are not a rational species – more a rationalising one. Perhaps higher cognitive ability just makes it easier to rationalise.
Matthew’s view is:

“much of these bias blind spots occur from the certainty and dogmatism that occurs from having too much confidence in holding certain positions.” A “strong skeptic identity” may also make you less receptive to feedback that challenges your worldview.”

Intellectual humility

So perhaps this explains the annoying confidence, even arrogance, that many people see in Sceptics (or Skeptics). Matthew’s solution, and it is worth considering, is intellectual humility:
“I would urge all of us to work on our “intellectual humility.” Intellectual humility is the psychological construct that can generally be defined as “understanding the limits of one’s knowledge.” Those with higher intellectual humility are more likely to be open to opposing viewpoints.  Additionally, research by Samuelson and colleagues (2015) found that “an intellectually arrogant person uses education in a prideful way to confer social status, while an intellectually humble person pursues education out of curiosity and love of learning.” Seems like too many skeptics may be intellectually arrogant instead of intellectually humble.
As I noted above, it’s often self-protective to believe we are correct and objective people. It’s certainly an unpleasant feeling to be proven wrong. However, working on our intellectual humility will make us more open to feedback. Yes, it may sting in the short term, but if we value truth, that’s a small price to pay.”

I think Matthew resorts to a bit of intellectual arrogance himself in this article as it has its own polemics. However, I fully agree with him about the desirability of intellectual humility.

Worth thinking about.

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Anti-fluoride “expert” finds the real reason oral health has improved – and it’s not fluoride

Anti-fluoride campaigners always promote people like Geoff Pain as “renowned” or “world experts.” They aren’t. Pain has no credible scientific publications on fluoride.

No, in fact, he claims lead is responsible for tooth decay and the improvement in oral health is a result of removing airborne lead contamination. And the “proof” is even in the title of his report – “Global Decline in Tooth Decay correlates with reduced Airborne Lead (Pb) but water Fluoridation prevents further progress

Mind you, the word “correlate” appears only twice in the document – once in the title and once in the abstract. Nowhere else. Scientists usually restrict the use of words like this to results of proper statistical analyses – but he presents no evidence of a correlation anywhere in the document.

OK, we shouldn’t expect any better. This document is just another one of a series of documents, dressed up as scientific publications, supported by cobbled together citations which are often are irrelevant or don’t support the claims made. Produced by Geoff Pain, well-known Australian anti-fluoride activist, whose concept of scientific publication is to upload his unreviewed documents on to Researchgate. I have written about his citation trawling and false “publication” before in my article  An anti-fluoride trick: Impressing the naive with citations

But, perhaps he is on to something. Irrespective of fluoride (he has a hangup about that element) perhaps lead is somehow implicated in oral health problems. So let’s see what the document actually claims.

It has three aims:

1: Rejection of all evidence of the beneficial effects of fluoridation

He describes the evidence for fluoridation as “false” and “absurd.”

Of course, he doesn’t consider for a minute any of the many studies providing evidence of beneficial effects – he just relies on the naive use of selected World Health Organisation (WHO) data which the Fluoride Action Network is well-known for. I have written about this before (see, for example, Fluoridation: Connett’s naive use of WHO data debunked).

This simply argues that the fact that oral health has improved over time in both fluoridated and unfluoridated countries is “proof” that fluoridation has no effect.

Here is the graph he uses:

This figure is meaningless because of the huge influence of inter-country differences on these data, irrespective of fluoridation. That doesn’t require a scientific training to see. These differences introduce so much noise into the data that no conclusion is possible about the influence of fluoridation. Robyn Whyman pointed this out in his report for the National Fluoridation Information Service – Does delayed tooth eruption negate the effect of water fluoridation?:

“Studies that appropriately compare the effectiveness of water fluoridation do not compare poorly controlled inter-country population samples. They generally compare age, sex, and where possible ethnicity matched groups from similar areas. Inter-country comparisons of health status, including oral health status, are notoriously difficult to interpret for cause and effect, because there are so many environmental, social and contextual differences that need to be considered.”

The figure does not differentiate between fluoridated and unfluoridated areas within countries – a comparison that is more valid. When we look at the same WHO data for fluoridated and unfluoridated areas we can see the beneficial effect. For example, in the data from the Republic of Ireland:

2: Evidence for an effect of lead exposure on oral health

I can accept that – but certainly would not go as far as Pain’s claim that “lead exposure reduction as the major factor in tooth decay decline.” In fact, the articles he cites suggest that the association of  lead exposure with tooth decay is probably weak in most cases.

For example, he cites Gemmel et al., (2002) but ignores what that paper actually says:

“In summary, our findings are consistent with those of several other recent studies (e.g., Campbell et al. 2000; Moss et al. 1999) in suggesting a weak association between children’s lead exposure and caries in primary teeth. The association was region specific, however, suggesting that its magnitude depends on the local distributions of other, more important caries risk factors such as fluoride exposure, diet, and other aspects of environment. The most likely direct role for lead exposure in the development of dental caries, therefore, is as a modifier of host susceptibility. We cannot reject the hypothesis, however, that an elevated lead level is a surrogate or proxy index of some other factor that is itself directly cariogenic.”

Similarly, he cites Martin et al., (2007) but ignores what that paper actually concluded:

“We conclude that this study provides only weak evidence, if any, for an association of low-level lead exposure with dental caries.”

Mind you, he also cites Wiener et al., (2015) who reported:

“This study indicated a strong association of blood lead levels with increasing numbers of carious teeth in children aged 24–72 months.”

But still not evidence that lead is the major factor involved.

Pain ignores suggestions that results may suggest modification of the role of fluoride

I wonder if those who indulge in citation trawling ever actually read the papers they cite. Far from Pain’s citations being evidence of a lack of effect from fluoridation, in almost all cases they suggest the observed effects could be due to modification of the more important effect of fluoride on oral health.

For example, Martin et al., (2007) point out:

” Mechanisms which have been offered to explain the potential association include lead effects on salivary gland development and function (Watson et al., 1997; Bowen, 2001), effects on enamel formation (Lawson et al., 1971; Kato et al., 1977; Appleton, 1991; Watson et al., 1997), and an interference with fluoride uptake in saliva (Gerlach et al., 2002). “

Come on Geoff. Spend some time and actually read the articles you have trawled for your citations.

3: Fluoridation means increase lead concentration in tap water

Having rejected any beneficial role for fluoride and presented lead as the major influence on oral health Pain now puts it all together to “prove” that fluoridation actually enhances tooth decay by increasing dietary lead intake. Why? Because of:

“deliberate addition of Lead as a major contaminant of phosphate fertilizer industrial waste used in Fluoridation plus the exacerbation of Plumbosolvency by Fluoride”

The first point about lead contamination of fluoridating chemicals relies in a naive interpretation of the certificates of analysis required for these chemicals. Just because a very low concentration of lead is recorded in these certificates does not mean this causes an increase in dietary lead intake.

I showed in the article Chemophobic scaremongering: Much ado about absolutely nothing that the fluoridating chemicals contribute less than 0.05% to the lead in tap water – already present from natural sources!

Pain’s reference to “exacerbation of Plumbosolvency” relies on a limited study which reported an association between blood lead levels in children and the treatment of tap water in the US. Of course, the release of lead from pipe fittings can be a problem irrespective of water treatment – which is why authorities recommend one should let the water run for a while first thing in the morning to get rid of such impurities. However, the studies Pain relies on seem to attribute plumbosolvency to specific chlorinating chemicals rather than fluoride.

One can make a simple check, however. In New Zealand authorities regularly make chemical analyses of their tap water available. These do not show increased lead concentrations after fluoridation.

Conclusion

So, again, Geoff Pain has indulged in citation trawling and confirmation bias to produce this report. The citations he uses do not support his claims.

Dietary intake of lead may be one of many factors influencing dental health – but his citations do not in any way support his assertion that it is the “major factor”. Nor do they support his claim that fluoridation does not have a beneficial effect on oral health.

In fact, it is Geoff Pain, not health authorities, who is making the “false” and “absurd” claims.

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Meat substitutes – prospects and new ethical questions

Nigel Latta tells us about a plant-based meat substitute – chicken-free chicken – produced by  SunFed meats. This is an example and not meant as an endorsement of any specific product.

I am deeply ashamed of it now – but at the time it seemed like an experience I couldn’t afford to miss. It was so exotic – and I was travelling.

Twenty years ago I ate at a restaurant in Johannesburg, the Republic of South Africa,  which specialised in meat dishes – from game animals. It was a real feast. Stews of ostrich, zebra, hippo, giraffe and other animal meats. Not something us New Zealanders normally experience.

But I no longer eat animal meats – and haven’t for several years. My decision is based on ethical considerations. So you can understand my shame.

Some might call me a weirdo – but I do not think my ethical decision is really all that unusual. Vegetarianism, veganism and similar dietary approaches are relatively common these days. And I think there are many more of us who resist labels but wish to avoid animal meats for basically ethical reasons. Even if only reducing animal meat consumption to rare occasions.

However, in common with others who avoid eating animal meat, I am surprised that there are still so few choices for us. Restaurant menus only seem to give token recognition of our existence, if at all, and the dishes on offer are often uninspiring.

On the other hand, there does seem to be a renewed interest in meat substitutes. Not only for health reasons but also because of the growing appreciation of how animal-based agriculture is harming our environment. Even in little old New Zealand which usually insists it is “clean and green” but is also proud of its efficient and intensive animal-based agricultural industry.

I welcome that interest. These days I have no problem finding or producing tasty plant-based meat substitutes for myself but it has taken some research effort. Products on supermarket shelves are few and far between. However, if you believe some recent news reports the arrival of tasty meat substitutes is so imminent the established agricultural industry is starting to worry.  A recent report citing an agribusiness spokesperson, Ian Proudfoot, reckons:

New Zealand meat and dairy producers needed to identify what level of risk the products presented for their industry and plan accordingly.

The threat of vegetarian alternatives to meat products was looming as companies were beginning to create products that would genuinely appeal to consumers, Mr Proudfoot said.

For example, US company Impossible Foods has developed a plant-based food that is said to closely resemble the taste and smell of meat – and has attracted $US150 million in investment.

“This is definitely going to happen in the next five years and it could start to happen in the next two to three years.”

He said in the dairy sector, New Zealand would have multiple alternative milk products – such as almond and hemp milk – competing with it, all of which were designed to meet specific consumers’ desires.

The current alternative meat market was less of a threat because it was aimed at wealthy consumers. However, this would change as the new “alternative protein” companies were bought up by bigger players in the food industry, he said.

What about animal-based meat substitutes?

The company Sunfed Foods is producing plant-based meat substitutes. However, it’s founder Shama Lee says there are another two alternatives:

  1. Cultured meats – these are grown from starter cells taken from animals such as stem cells. This is the method Sergey Brin bankrolled to produce his rich-man’s hamburgers, and
  2. Bioengineered meat – where animal protein is grown from a bioengineered culture of yeast cells.

These alternatives may be a bit further down the line but could be in your supermarkets in 10 or 20ears.

I don’t doubt the possibilities – but I will believe it when I see it. I know for a fact that it is possible to produce very tasty plant-based meat alternatives but our supermarkets are hardly swamped with these products. In most cases, they still need to be home produced in New Zealand. So will cultured meat products get the supermarket shelf space – especially if competing with traditional meats?

Still, such products should solve the ethical dilemma many of us face. We would be able to eat “real” meat without worrying about how the animals had been treated and slaughtered.

Is there a new ethical dilemma?

OK, if I am still around when it happens I may be able to take part in a feast of stews like that in Johannesburg but using cultured meat instead of real animal meat. I could still get to taste the ostrich, hippo, zebra and giraffe stews without any feelings of guilt.

However,  will it stop there? We could go even more exotic.

Just think about it. We could also produce cultured meat using starter cells from humans! Imagine eating human meat knowing that nobody had been harmed in the preparation of the product!

Would this make cannibalism respectable? In fact, who could resist such artificial human meat – it would be so exotic.

And once more people got a taste for cultured human meat – will there be some adventurous people wanting to eat the “real” meat – uncultured human meat?

The mind boggles! One thing for sure – like all human advances there will be new ethical questions. And, no doubt, ideological groups and religions willing to use these ethical issues to promote guilt.

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New fluoride debate falters

Characters debate the “fluoride conspiracy” in Kubrick’s Dr Strangelove

What is it with these anti-fluoride campaigners – and particularly their leaders? They make a song and dance about having “science on their side.” They will heavily promote the latest research and papers if they can argue that they confirm their bias. And they will email politicians or make submissions to local bodies making scientific claims – often with citations and long lists of references.

But we simply can not get them to enter into a good faith scientific discussion of the sort I suggested in Do we need a new fluoride debate?

I thought this was going to happen. Bill Osmunson, the current Direct of the Fluoride Action Network (FAN), had agreed and even produced an initial article for posting. But he has now pulled out and asked me not to post his article. Apparently, my critique of a recent paper by him and his colleagues from FAN (see Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study) was the straw that broke the camels back as far as he was concerned.

Talk about tiptoeing around a discussion partner. How can one have a discussion with someone this sensitive?

Excuses, excuses!

This is the explanation he gives for his withdrawal from the planned exchange:

“I have second thoughts about a discussion with you.  Do not publish my comments.*

After reading your comments in response to Neurath, it became obvious that you have no interest in discovering the truth or protecting the public.  Nor do you have reasonable judgment to evaluate research.

You do have good mechanical skills, but not judgment.

You correctly take weaker arguments and point out they are weak.  But you do not comment or appreciate the main more powerful issues.  Your comments make it sound like there is no value because some points have lower value.  Only a person who carefully rereads McLaren and Neurath, and then your comments understands some of your points are valid and you have missed others which are powerful.

In addition, you use derogatory, unprofessional mocking terms to attack the person instead of the issues.  I’m not interested in being your porky or sparky or pimp.

You are unprofessional and are not worth the time.”

  • The “comments” Bill refers to are a 55-page pdf file he sent me as the first post in our exchange. We were discussing a shorter form more suitable for a blog post when he decided to back out.

Mind you, in a previous email he had acknowledged that his mates (presumably in FAN) were unhappy about him participating in this good-faith scientific exchange. He wrote:

“Several people have told me not to respond to you, because you are unprofessional with your statements and comments.  You attack the messenger instead of the message and you have such severe bias and faith in fluoride that you must have worked for the tobacco companies to learn your strident blind bias.  
OK, I gave you a try once before and found you to be violent with your personal attacks and lack of judgment.”
 Sounds like “excuses, excuses,” to me. Surely I am not such a horrible person? I asked Bill to identify anything in my exchange with Paul Connett (see The Fluoride Debate) where I had behaved in the way he charged. He couldn’t. And I challenge anyone else to identify such behaviour on my part in that exchange.

Bill Osmunson and his mates claim I behaved badly in this exchange with Paul Connett – but they refuse to give a single example

 I can only conclude that the people at FAN are unable to provide good scientific arguments to support their case. They may well produce documents with lists of citations and references with “sciency” sounding claims. But they will not allow their claims to undergo the sort of critique normal in the scientific community.
Still – I am willing to be proven wrong. if Bill feels that he doesn;t have the scientific background for this sort of exchange perhaps Chris Neurath, Harvey Limeback or one of the other authors from FAN of the article I critiqued in Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study) could take his place.
The offer is open.

Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study

Anti-fluoride group, Fluoride Action Network, ironically stamps their own critique of the Calgary fluoridation cessation study as “debunked.”

Anti-fluoride campaigners have launched another attack on a Canadian fluoridation cessation study. They claim it is flawed – but there is a huge flaw in their own critique.

I discussed their original attack in February last year (see Anti-fluoridationist’s flawed attacks on Calgary study). But this new attack is based on a published critique of the original study. I think that is good progress – the anti-fluoride campaigners have made a detailed critique and published it in the journal which published the original paper. The original authors have then responded. This is how things should be done.

Timeline

For those of you with the interest and time who want to go into the details, the original study was published in:

McLaren L, Patterson S, Thawer S, Faris P, McNeil D, Potestio M, Shwart L. (2016) Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices. Community Dent Oral Epidemiol 2016.

The anti-fluoride critique was recently published in:

Neurath, C., Beck, J. S., Limeback, H., Sprules, W. G., Connett, M., Osmunson, B., & Davis, D. R. (2017). Limitations of fluoridation effectiveness studies: Lessons from Alberta, Canada. Community Dentistry and Oral Epidemiology, (October 2016), 1–7.

The response from the original authors was then published in:

McLaren, L., Patterson, S., Thawer, S., Faris, P., McNeil, D., & Potestio, M. (2017). Fluoridation cessation: More science from Alberta. Community Dentistry and Oral Epidemiology, (October), 1–3.

Other data which have been used in the critique and which I will use here can be found in:

McLaren, L., McNeil, D. A., Potestio, M., Patterson, S., Thawer, S., Faris, P., … Shwart, L. (2016). Equity in children’s dental caries before and after cessation of community water fluoridation: differential impact by dental insurance status and geographic material deprivation. International Journal for Equity in Health, 15(1), 24.

And:

McLaren, L., Patterson, S., Thawer, S., Faris, P., McNeil, D., Potestioa, M. L., & Shwart. L. (2017). Exploring the short-term impact of community water fluoridation cessation on children’s dental caries: a natural experiment in Alberta, Canada. Public Health, 146, 56–64.

Most of the authors of the critique are listed as members of the Fluoride Action Network (FAN) team and I can understand that FAN would feel proud that their critique was published. However, I feel their press release was rather underhand to imply the original study is:

“seriously flawed science  . . . Citizens should be concerned that their tax dollars have funded this biased work.”

And that the work was funded by state and public bodies:

“whose policy is to promote fluoridation.”

But let’s look at the critique itself – because it has some pretty big flaws itself.

What did the original study find?

My article, Anti-fluoridationist’s flawed attacks on Calgary study describes the details of this study. But briefly, it showed that child tooth decay increased in the Canadian city of Calgary after cessation of fluoridation. It used a comparison fluoridated city (the nearby and similar sized city of Edmonton) – and just as well because tooth decay also increased in that city during that time. However, there was still an increase in tooth decay in Calgary after cessation of fluoridation even after correction for the increase due to other factors apparent in Edmonton.

What did the critique claim?

A number of the criticisms are debatable and relatively minor.

How suitable was Edmonton as a comparison city? Neurath et al., (2017) claim it wasn’t suitable (but did not suggest a better alternative). McLaren et al., (2017) claim there is “no better comparison community for Calgary than Edmonton.”

Confounding – Neurath claims consideration of confounding factors was inadequate. McLaren et al., (2017) refer to extra data in two other papers and describes their consideration of several likely confounding factors like public health programmes and use of sealants. Whether the correct factors or sufficient factors were considered is always a bone of contention between authors and critics and, in the end, available data and funding decides.

Study design – Neurath et al., (2017) argue for randomised controlled trials. McLaren et al. (2017) point out that in studies of social programmes one must go with what exists. They say:

“While we agree with the value of stronger designs, one must be thoughtful about evaluation of public health measures, which by definition are complex and context-dependent. We used the best available
data and design for our circumstances”

Data ignored?

But Neurath et al (2017)’s major criticism is that some important data was ignored. And they claim that when that data is included the conclusions are not valid.

Of course, the FAN authors are stretching things quite a bit. The original study was based on data for tooth surfaces – the decay, extracted and filled tooth surfaces (defs). This was used as it is more sensitive than the tooth data itself – the decayed missing and filled teeth (deft).

Data for defs were only available for the 2004/05 and 2014/15 surveys. Unfortunately, there were no defs data for the pre-cessation period closer to the time of cessation (2011). That is the sort of problem researchers face when dealing with existing surveys and existing social programmes.

But the bright sparks at FAN latched on to the fact there was a survey with deft data in Calgary closer to the cessation time – 2009/2010. The fact that there was no equivalent survey for Edmonton didn’t hold them back – they proceeded to imply the 2009/2010 data had been purposely held back, despite McLaren making clear she could not use that data for Calgary in the absence of similar data for Edmonton. That would have negated the requirement for a comparison city and the existing data surely shows that requirement was very wise.

So Neurath et al., (2017) chose to ignore the obvious requirement for a comparison city and proceeded to argue their case on the Calgary data alone. They argued the study was “fatally flawed” and that “key data [was] omitted.” The argument implied the study was somehow fraudulent and that the authors had hidden the 2009/2010 survey data – despite the fact this data is used in another of their papers!

Neurath et al., (2017) pretend that a comparison city is not really necessary – relying only on the tooth data (deft) for Calgary they argue that as 50% of the increased in tooth decay had occurred between the 2004/05 and 2009/10 surveys then the increases seen after cessation of fluoridation was due to the same trend (see their Figure 1 below). They argued this proved that cessation of fluoridation had no effect. Ignoring completely the Edmonton data.

So, an obvious flaw in their critique – but wait, there is more! They actually go so far as to falsify data.

Falsifying a “correction factor”

Not satisfied with the plots in Figure 1B they found a way to make the data look even worse for McLaren et al. (2015). They came up with a “correction” factor to convert the deft data for 2009/2010 survey into defs data. Here is their Figure 2 using the “converted” deft data

Looks bad, doesn’t it?

However, the trick is in the way the conversion factor is calculated. They “used the ratio of defs to deft in the 2013/2014 survey to make the conversion.” The table below for subset (dmft>0) data they used shows this produces a conversion factor of 2.41 – big enough to dramatically push the 2009/10 data point right up so that it is sitting on the Edmonton “trend line” in their Figure 2 above.

But they could have equally used the ratio of defs/deft in the 2004/2005 survey to make the conversion. That produces a much lower conversion factor of 1.63 – which is not at all consistent with their claim “when we applied this conversion [2.41] to the 2004/2005 Calgary survey, where both deft and defs are known, the calculated defs was very close to the known defs.”

In fact, it may have been more appropriate to take the average conversion factors from the two available surveys. In the figure below I have done this (green data point) and compared this with the use of the conversion factors from the 2004/05 survey (purple data point) and that from the 2004/15 survey used by Neurath et al (yellow data point).

I guess this shows the danger of making these sort of adjustments – especially when there is a bias to confirm. And also that readers should beware of vague assertions of the sort:

“when we applied this conversion [2.41] to the 2004/2005 Calgary survey, where both deft and defs are known, the calculated defs was very close to the known defs.”

Conclusion

The McLaren et al., (2017) study has its limitations, limitations admitted and described by the authors. But, it is the FAN critique of Neurath et al., (2017) rather than the original study, that is fatally flawed. Flawed because of confirmation bias and a porky.

1: They ignored the necessary use of a comparison city and assumed the increase in tooth decay in Calgary was linear over the time between the two surveys McLaren at al used.

2: The use of any correction factor would be questionable but Neurath et al., (20127) clearly used a biased value to suit their argument. Further, they purposely misrepresented their correction factor by implying a similar value would have been obtained from the 2004/2005 survey data. Completely wrong.

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