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credulous reporting around cancer Alison Campbell Dec 02

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This is a really difficult post to write. The word ‘cancer’ evokes any number of fears & unpleasant images, and I can’t imagine something worse than discovering that a child has cancer. (Nor can I be certain of my own reaction, if I should find myself in that position.) But that doesn’t excuse credulous reporting on the issue, most recently exemplified in this story (in the ‘Life & Style’ section) in the NZ Herald.

The story is about the use of plant-based compounds, called salvestrols, for children who’ve been diagnosed with a range of cancers. Now, a search for ‘salvestrols’ brings up a rather large number of websites making all sorts of claims for their efficacy, but a search for ‘scholarly articles’ narrows things down a bit. The first such paper to come up appears to be the one used to support the claims made by the Herald piece, & was published in the Journal of Orthomolecular Medicine in 2007. (It’s worth noting that this particular field of study is not widely supported by science-based medicine and that the journal itself isn’t indexed by Medline. I was intrigued to see that the editor of JOM has compared it to Medical Hypotheses, because really, that’s not a good advertisement.)

Those claims include the hypothesis that salvestrols are used by our bodies to destroy cancer cells (referencing an earlier study by the same authors) and that modern practices around food-growing & preparation reduce the amount of salvestrols in our diet (with little evidence for this cited in support). Unfortunately the Herald’s reporter simply presented these ideas as if they are widely-accepted facts:

they trigger a process in the body allowing it to kill diseased cells. But they have been depleted from food through modern farming and production techniques which have drastically altered diets.

The paper itself discusses case studies ie there are no controlled trials; while the case studies may suggest routes for future research they should be viewed as tentative, at best. Further, it makes the following claim:

First, it is not harmful. The toxins produced through the metabolism of Salvestrols by CYP1B1 are confined to the cancer cells and are exhausted through the destruction of the cell.

And yet GSK stopped a trial of a salvestrol (reservatrol) in cancer patients because not only was there no evidence of efficacy, there was evidence of harm (kidney damage). Hardly suprising as compounds such as reservatrol appear to have an effect on quite a range of metabolic pathways in our bodies.

Now, that information was fairly easy to find, so it was really, really disappointing to see the Herald’s reporter referencing the JOM – and the British Naturopathic Journal – as being the best source of information on this subject.

It’s also important to note that the people identified in the Herald story as successfully using salvestrols as a cancer treatment have also had surgery & in some cases chemotherapy as well. It’s entirely possible that the medical treatments alone have resulted in patients being in remission – and without properly-designed clinical trials there’s no way to identify any impact of the plant compounds. Nor is it enough to say that it’s “common sense” that they work; as a colleague’s said to me, blood-letting was also seen as a common-sense treatment for pretty much everything that ailed you.

This isn’t the first time that we’ve seen such poor reporting around such a serious issue; sadly, I suspect it won’t be the last.
 

weapons-grade foolishness from the ‘food babe’ Alison Campbell Nov 18

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Today, we move on to just plain, flaming, weapons-grade foolishness. Foolishness that is, unfortunately, spread to a rather wide audience.

Vani Hari is the self-described ‘Food Babe’, on a mission to ‘make America’s food safer’. According to Ms Hari, if you can’t pronounce a food item’s ingredients, you shouldn’t be eating it1. I guess she’s never seen information like this, then (graphic by the wonderful James Kennedy).

Ingredients of an All-Natural Banana

But I digress. Recently Ms Hari wrote a piece giving her advice around flying. (It’s since been removed from her site, but the internet has ways of ensuring that things don’t just disappear, so you can read the post in its entirety here – for as long as it remains there, or there’s a screen cap here.) The nature of some of her comments do not inspire me with confidence.

A few facts about what airplanes do to your body -

When your body is at seriously high altitude, your body under goes [sic] some serious pressure. Think about it – Airplaines thrive in places we don’t. You are traveling in a pressurized cabin, and when your body is pressurized, it gets really compressed!

I am still trying to get my head around the idea of inanimate objects like aeroplanes ‘thriving’. That aside, our bodies are not placed under greater pressure when at altitude. Yes, plane cabins are pressurised, but that pressure’s still less than what we’re exposed to at sea level.

Compression leads to all sorts of issues. First off your body’s digestive organs start to shrink, taxing your ability to digest large quantities of food. Secondly, this compression reduces the ability for your body to normally circulate blood through your blood vessels. Sitting down for long hours while this is happening, exacerbates these issues, leading to what they call “Economy Class Syndrome.” Economy Class Syndrome results the action [sic] of sitting in a cramped space for a long period of time, thus resulting in blood flow loss to the legs.

Yes, aeroplane passengers are subject to increased risks relating to poor circulation, but they’ve got nothing to do with ‘compression’ due to supposedly high cabin pressure & everything to do with simply sitting still in cramped conditions for prolonged periods of time. In fact, air travellers are advised to use compression stockings to help mitigate those risks. (Ms Hari does give some sensible advice on combatting this.)

The air you are breathing on an airplane is recycled from directly outside of your window. That means you are breathing everything that the airplanes gives off and is flying through. The air that is pumped in isn’t pure oxygen either, it’s mixed with nitrogen, sometimes almost at 50%. To pump a greater amount of oxygen in costs money in terms of fuel and the airlines know this! The nitrogen may affect the times and dosages of medications, make you feel bloated and cause your ankles and joints to swell.

This is such a basic science fail. Passengers don’t breathe in ‘everything the airplane gives off’ (details of where cabin air comes from are here). And Earth to Vani: the air you breathe has never been ‘pure oxygen’, whether you’re at ground level or 11,000m up in the air – probably just as well, really, given the reactivity of the pure stuff. This is so easily checked (image from geocraft.com):

Now, this may seem laughable. Someone is ill-informed & shares that lack of knowledge rather widely. But that’s not doing any actual harm, is it?

Except, I think it is. Why? Because the Food Babe is encouraging and pandering to chemophobia and scientific illiteracy (and, sad to say, has a wide audience for this nonsense: several hundred thousand followers on FB, for example). And when you’re also spreading anti-vaccine misinformation to that number of followers then yes, you have real potential to do harm.

 

1 Sad to say, one of our local NZ companies has bought into the ‘no long words’ meme. It’s worth remembering that some ‘nasties’ have very short names, while the names of many important proteins are multisyllabic.

but surely if it does no harm… Alison Campbell Nov 14

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With Acupuncture Week coming up, I thought it might be timely to revisit one of my earlier posts on the subject. Since I originally wrote this piece, there’s been at least one high-profile example of needles being found where they definitely shouldn’t have been: a 7cm needle found in the lung of a former president of South Korea.

There’s a lot been written in the blogosphere around what’s known as ‘complementary & alternative medicine.’ (I would argue that there’s no such thing – if it works ie improves/cures the patient’s health, then it’s medicine). In any debate around the use of CAM someone is likely to say that at least it does no harm. For things like homeopathy you could argue that since the client is swallowing only water or sugar pills, with no active principle present, then they’re highly unlikely to come to harm (witness the 10-21 homeopathic ‘overdose’). The counterargument here is that if the patient relies solely on homeopathy for anything beyond self-limiting conditions then there is in fact considerable potential for harm.

With other ‘treatments’ the potential for harm is more apparent. And in some cases the harm can be real. In a 2010 issue of the New Zealand Medical Journal, Brian Kennedy & Lutz Beckert reported on the case of a woman whose acupunturist  left her with a case of pneumothorax. This is not a trivial problem: pneumothoraxis where air builds up within the chest cavity, in the space round a lung, as the result of chest trauma or due to a spontaneous breach in the lung itself – or in this case, because an acupncture needle pierced the lung. This puts pressure on the lung, & as a result the lung collapses. (Pneumothorax has also had medical applications– in Sonja Davies‘ autobiography, Bread & Roses, she describes it as a treatment for tuberculosis. Apparently collapsing the affected lung makes it more difficult for the tuberculosis bacilli to survive & grow, so the lung has a chance to recover.)

In the case described by Kennedy & Beckert, the patient “became acutely short of breath, following introduction of an acupuncture needle into the right side of her chest posteriorly. She developed ‘tightness’ … and associated chest pain” & very sensibly left the clinic, went home, & called an ambulance when her symptoms (typical of pneumothorax) got worse. An X-ray showed that her lung had collapsed, & doctors used a needle to remove 450ml of air from the pleural space around the lung. The next morning the pneumothorax had recurred, which meant surgery to inset a ‘drain’ into her chest wall. After the lung reinflated the drain was removed (& presumably the opening was sealed) & she went home a day later.

Madsen, Gotzsche & Hrobjartsson (2009) performed a meta-analysis of clinical trials looking at acupuncture as a treatment for pain. They looked at data from a total of 3025 patients who received either ‘real’ acupuncture, ‘sham’ (placebo) acupuncture, & no treatment. Their conclusions: there was “a small analgesic effect of acupuncture …, which seems to lack clinical relevance and cannot be clearly distinguished from bias. Whether needling at acupuncture points, or at any site, reduces pain independently of the psychological impact of the treatment ritual is unclear.” (As Orac comments, on a related study, “the larger and better designed the study, the less likely it is to find a treatment effect greater than placebo due to the treatment.”)

Given the following that acupuncture appears to have, people will no doubt continue to seek it out for various ills, regardless of the fact that it performs no better than placebo. In which case, they need to be aware that adverse events like the one described by Kennedy & Beckert, although very rare, can still occur. (These authors list ”transmission of diseases, needle fragments left in the body, nerve damage, pneumothorax, pneumoperitoneum [air in the abdominal cavity], organ puncture, cardiac tamponade [accumulation of fluid around the heart] and osteomyelitis [a bone infection]” as major adverse events, albeit extremely rare ones.) They conclude that as these events are generally associated with poorly-trained practitioners, if people do seek out acupuncture treatment they should choose their practitioner carefully – and if treatment involves acupuncture of the chest wall, then the client should be warned about the risks of pneumothorax by the practitioner concerned.

But as Darcy says over on SciBlogs, why go down this route at all?

Brian Kennedy, & Lutz Beckert (2010). A case of acupuncture-induced pneumothorax The New Zealand Medical Journal, 123 (1320) http://www.nzma.org.nz/journal/123-1320/4258

M.V.Madsen, P.C.Gotzsche & A.Hrobjartsson (2009) Acupuncture treatment for pain: systematic review of randomised clinical trials with acupuncture, placebo acupuncture, and no acupuncture groups. BMJ 338: a3115

a tale of rare blood groups, or, ‘the man with the golden blood’ Alison Campbell Nov 03

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One of the topics we cover in first-year biology is human blood groups – it’s discussed during genetics classes & also touched on when looking at how immune systems function. I give the genetics classes and, being a regular blood donor myself, thought I knew a bit about at least the common blood groups and their inheritance. But there’s always more to learn, something I was reminded of when I read a fascinating story about people with truly rare blood types: “The man with the golden blood”.

There’s ‘Thomas’, for example: a man who lacks the Rhesus markers completely & so is classified as Rhnull  - in 2010 he was one of an exclusive global club of 43 individuals (of whom only 6 regularly donate their blood). And James, who is ‘Lutheran b negative’, and one of only 550 active donors for this blood type.

This makes known donors precious, in that if someone else with the same group needs a blood transfusion, there are very very few people around the globe who might be able to help them. And helping comes at a cost to the donors, for – as the story tells us – it’s actually easier in many cases to move people across borders than it is to move blood, but because many countries don’t pay donors, then that movement may well be at the donor’s expense. It’s also difficult for people like ‘Thomas’, with his vanishingly rare blood group: his blood can be used by anyone who’s Rhesus negative, but he can receive blood only from another Rhnull person, which means he has to be reasonably careful not to put himself in harm’s way (although he does still go skiing!).

Quite an eye-opener – and a tale I’ll be including in next year’s class.

‘alternative’ medicine – numbers using it =/= evidence it works Alison Campbell Oct 26

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Recently some friends & I were discussing the use of what might be called ‘Supplementary, Complementary, & Alternative Medicine’ – a group of ‘therapies’ that includes (but is not limited to) things like homeopathy, reiki, acupuncture, ear candling, and cranio-sacral therapy, and for which there is little or no evidence of efficacy.

One of the reasons given by those supporting their use is a form of the ‘argument from popularity’ logical fallacy: ‘but look at how many people use them. They can’t all be wrong!’ That viewpoint is exemplified here, in the claim that a large number of doctors are now recommending alternative therapies to their patients, or providing these therapies themselves. The list offered at one such practice includes

psychologists, naturopaths, nutritionists, cranio osteopaths, massage therapists, hypnotherapists, yoga practitioners, an acupuncturist and a breast thermography technician.

Now, massage, yoga (exercise), and psychology are hardly ‘alternative’, although including them in the list then allows one to inflate the number of people supposedly seeking out alternative health modalities. Most of the rest have been addressed far better than I could by Orac (see here, for example, and here) and the authors of the Science-Based Medicine site.

But let’s not get distracted. As my friend Renee said: the claim is that lots of people use these modalities, therefore they must be good; a claim supposedly supported by “the impressive statistics showing people are now willing en mass [sic] to spend their dollars on integrated health care”. What we should be asking to see are the statistics showing the efficacy of such care, before we start spending any more of our scarce health dollars on it.

‘paleo’ diet? or paleofantasy? Alison Campbell Oct 17

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The ‘paleo’ diet story on Campbell Live tonight spurred me to finish my review of one of the most entertaining popular books on genetics that I have read for some time. Entertaining, and informative, in equal measure. I wonder what author Marlene Zuk would have made of the TV story.

book cover Marlene Zuk (2013) Paleofantasy: what evolution really tells us about sex,diet, and how we live.  Norton (New York)

ISBN 978-0-393-34792-0 (paperback)

For in that story we heard gems like this: “It’s a commitment to eating food that is unadulterated, eating food in its most natural state.” Paleo proponents (says the TV story) believe our most natural diet is that of our Palaeolithic cavemen ancestors. Somehow I doubt our ‘cavemen’ ancestors were eating avocados, beetroot, bacon or kale. (There’s also an air of chemophobia, with one proponent of paleo eating stating that their diet contains “[n]othing nasty and nothing you can’t pronounce” – which reminded me of the series of posters by Australian teacher James Kennedy, showing the list of chemical compounds found in natural food items: blueberries, anyone?).

Proponents of the so-called paleo diet seem to think that humans haven’t evolved in the last 10,000 years (since the advent of agriculture), and that this means that our bodies aren’t ‘designed’ to cope with the products of the agricultural revolution. (This, while eating foods that bear little resemblance to their Palaeolithic counterparts. Look at teosinte, the ancestor of maize, for example: small, stone-hard kernels arranged in a few lines on a stalk. Nothing like the fat, soft, juicy kernels on a modern cob of corn.)

As Zuk notes, the paleofantasy happily assumes that at some point in the past (around 10,000 to 40,000 years ago, depending on who you’re listening to), humans were perfectly adapted to their environment, including their diet. But, she asks, why hark back to that particular point in time?

would our cave-dwelling forebears have felt nostalga for the days before they were bipedal, when life was good and the trees were a comfort zone?

Plus, of course, there’s the question of just which ’cavemen’ we’re aspiring to be like. We’ve no guarantee that the life-styles of modern hunter-gatherer populations are a good approximation of life 40,000 years ago. Should we be Inuit, or Kung?

And there’s no reason for us to have stopped adapting to evolutionary pressures once agriculture became the mainstay of human populations – in fact, there’s a great deal of evidence to the contrary, some of which I’ve written about previously -the evolution of lactase tolerance, for example. Similarly, with the spread of arable farming, those with the ability to digest grains would be at an advantage, to the extent that there is a higher number of copies of the gene coding for salivary amylase in populations with a long history of eating starchy grains, compared to populations where the diet has traditionally been low in starches. And Zuk provides many examples of just how rapid evolutionary change can be, in humans and in other animals (changes in cane toad morphology, in the short span of time since their arrival in Australia, are a particularly elegant case in point). The final chapter, which gives considerable detail in answering the question, are we still evolving, would be very useful to biology teachers during human evolution classes.

In other words,

[t]he notion that humans got to a point in evolutionary history when their bodies were somehow in sync with the environment, and that some time later we went astray from those roots – whether because of the advent of agriculture, the invention of the bow and arrow, or the availability of the hamburger – reflects a misunderstanding of evolution.

As the extended title of her book points out, Zuk feels that the paleofantasy extends well beyond the current diet fad. It influences beliefs about health and illness, about family life, about sex. (This last is the focus of all sorts of wistful imaginings: the book provides an entertaining sample of these.) Do bonobos, for example, really provide a good model for how human sexual activity might have been before modern mores took over? I can’t see it myself: humans and their chimpanzee cousins have follwowed separate evolutionary trajectories for 5-6 million years, and there’s no good reason why either species should closely resemble the last common ancestor. And that goes for aspects of intimate morphology as much as for behaviour: I did not know that chimpanzees have penis spines –  ”hardened growths that may serve to sweep away the sperm of previous mates.”

Zuk concludes that the paleofantasy is just that, a fairy tale – and one that limits our understanding of our own biology and evolutionary history:

But to assume that we evolved until we reached a particular point and now are unlikely to change for the rest of history, or to view ourselves as relics hampered by a self-inflicted mismatch between our environment and our genes, is to miss out on some of the most exciting new developments in evolutionary biology.

 

Anyone interested in hearing Professor Zuk speak should check out the details of her upcoming lecture tour. I’ll be grabbing a ticket to the Hamilton event!

 

there’s the alarming news about ebola, & then there’s this Alison Campbell Aug 03

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Over on Sciblogs, Siouxsie Wiles has been writing about the spread of an Ebola virus outbreak in west Africa (here  here, for example). It’s alarming stuff: a virus with a high mortality rate, in combination with the potential for infected people to travel more widely than in the past before succumbing.

Sadly, it didn’t take long for the pedlars of pseudoscientific nonsense to get on the bandwagon. First it was homeopathy (apparently homeopathic concentrations of rattlesnake venom and other ‘remedies’ will do the trick – I wonder how they found that out?) In his blog post on this, Orac has commented

You know what they call an Ebola victim foolish enough to use these five homeopathic remedies in the hope of curing their disease? Almost certainly dead, that’s what!

Indeed.

And then there’s this. I should really give that page to my first-year bio students & see what they make of it: they’d certainly pick up on the author’s statement that our cells have walls! What’s more:

It’s impossible for a virus to live in the presence of pure, unadulterated cinnamon oil, so getting that oil into our bloodstreams to create an environment hostile to the virus is important.

Viruses are only active within living cells, and I’m fairly confident in saying that our own cells can’t live in “pure, unadulterated cinnamon oil” either. (I do want to know, though, why the author feels that one must anoint one’s feet with the stuff!)

However, the page does have references, and we’re urged to read them, so let’s look at those sources to see if they back up the claims being made for cinnamon oil. There are “13 studies on cinnamon oil and viruses” from PubMed, for example, as well as a couple of in vitro studies.

Well yes, yes, there are – but I doubt the page’s author actually read them, despite asking their readers to check the links. For several references of that PubMed list are for various studies that used LEC (Long-Evans Cinnamon) rats, while others are discussing avian flu in a range of waterfowl that includes cinnamon teal – nothing to do with using an essential oil against viruses! Of the remainder, one is a study of herbal medicines that include cinnamon bark (not oil); one looks at the efficacy of a range of traditional medicines (again, including cinnamon bark) on baculovirus in silkworms; two others look at using flavonoids (hint: not oils) from cinnamon as a potential drug in fighting HIV.

I will confess to being underwhelmed. And concerned that anyone might take this stuff seriously.

gmo myths & mythinformation Alison Campbell Jul 28

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The GMOLOL group on Facebook regularly posts on the subject of Genetically Modified Organisms (GMOs) and more recently – like many other pages – about the outrageous claims by the self-styled “Health Ranger” about Monsanto, likening the company & pretty much anyone with anything positive to say about GMOs to the Nazi regime of WWII. (NB he’s actually gone back & added a ‘preface’ to the original post at that link, due at least in part to the internet fuss that followed his original posting.) Fairly soon after another webpage posted names & details of scientists working on or speaking in favour of GMOs, which was unsurprisingly viewed as quite threatening by at least some of those named. There’s an interesting bit of forensic work on the 2 pages & the sequence in which they appeared here. And Orac has a thoughtful commentary here.

It was also not a surprise to see the Ranger using myth to make his case: claiming here, for example, that GMOs have led to widespread farmer suicides in India. No sense in letting the truth get in the way of a good story, I suppose. Especially when it turns out to be rather more complex.

Of course, he is ignoring the fact that we have been selecting for genetically modified organisms for at least as long as we’ve had agriculture and domesticated animals. Sweetcorn or watermelons, anyone? Let alone that horizontal gene transfer is an excellent mover of genes that can link widely separated taxonomic groups; this example of fungi using bacterial genes to form nodules on plant roots is a case in point.

I’m guessing he wouldn’t like the idea of GM insulin or using GM mosquitoes to control the spread of dengue fever, either.

The internet can be a fun place to play & to find information, but alas! it’s also made it so much easier to spread mythinformation to a much wider audience than ever before.

helicobacter pylori and the complexity of the human microbiome Alison Campbell Jul 24

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In their first-year microbiology lectures. our students hear about Helicobacter pylori, the bacterium associated with the development of gastric ulcers (a discovery that eventually saw Barry Marshall and Robin Warren receive the 2005 Nobel Prize for Physology or Medicine). The trouble is, I suspect that this is all that they hear about a story that is considerably more complex.

The story of H.pylori is just one part of Jessica Snyder Sach’s highly readable and thoroughly-referenced book, Good Germs, Bad Germs, which introduces the reader to the complexities of the human microbiome: the intricate microbial ecosystems found on and within the human body.

Good Germs, Bad Germs: health and survival in a bacterial world. Jessica Snyder Sachs (2008) pub. Hill & Wang. ISBN (e-book): 0809016427

The book begins with the harrowing tale of a young man’s death from a rampant MRSA infection, and of a child living with multiple life-threatening allergies.- two tales linked by the unforseen effects of our overuse of anitbiotics and our fixation on hygiene. (Actually, the former was not entirely unseen: in his 1945 Nobel Prize lecture, Alexander Fleming commented on the possibility that overuse of penicillin could see the development of resistant bacteria. Unfortunately, at the time this warning went unheeded – if indeed it was really heard – for example, penicillin was available as an over-the-counter drug in the US for almost a decade after its introduction in the 1950s, which would undoubtedly have contributed to the development of resistant strains of microbes.)

Then, after an introduction to the “war on germs” and scientists’ search for the ‘magic bullets’ that would (it was hoped) allow us to vanquish them forever, it’s on to “life on man”. Wherein I learned heaps, including the thought-provoking suggestion that there may be some adaptive significance to the fact that babies usually exit the vagina with their heads face backwards, towards the mother’s anus. For babies guts are colonised by bacteria very soon after birth – & they may receive an inoculum of faecal matter on the way out, to join the lactobacilli  from the vagina itself and bifiobacteria from breast milk.

Incidentally, while all this may sound uncomfortably germy, there’s good evidence that the gut microflora are essential for survival. Lab animals reared in absolutely germ-free conditions, & whose guts never develop a microbial flora, fail to thrive. What’s more, Snyder Sachs  comments that the combined acction of several species of intestinal bacteria “liberate as much as 30 percent of the calories a person absorbs from food, especially from high carbohydrate meals.”

Reading on – and it was really hard to put this book down! – you’ll hear about the hygiene hypothesis, which suggests that many of the inflammatory diseases that plague us today are an unforeseen result of lives that are too clean. Along with this is the ‘dirt vaccine’: the idea that vaccination with a mycoplasma may help to redirect the overzealous immune response underlying many allergies. Then it’s on to a deeper look at the development of antibiotic resistance and the rise of the superbugs, which has been exacerbated by the widespread use of antibiotics in farm animals. (Encouragingly, Snyder Sachs notes that banning this use, as in the Netherlands, can lead to a reduction in ‘superbug’ prevalence.) And finally, we look at our options for the future, and whether we can find a way to live in balance with our burgeoning microbial ecosystems.

And H.pylori? It turns out that this particular bacterium has been with us for at least 60,000 years, something that’s been used to track human migration patterns that began when Homo sapiens first left Africa. H.pylori colonises the stomach in the first few months of life, before gastric acid secretion really ramps up, and can actually affect that acid secretion, lowering the pH enough that Helicobacter can survive but most other species are killed. There is a plus to this: the lowered pH reduces the effects of acid reflux & the development of oesophageal cancer. But then, there’s those gastric ulcers – which apparently didn’t really become an issue until the 1830s, when this was mainly a disease of the upper classes, possibly linked to a decline in colonisation related to improved sanitation and the use of early antibiotic products. And gastric ulcers

remain virtually unknown in undeveloped regions of the world such as Africa, where most people become colonised in infancy. It may be that delaying or disrupting H.pylori colonisation with water sanitation or antibiotics has somehow altered the immunological ‘truce’ that this microbe forged with our immune systems over thousands, possibly millions, of years.

I like the full, more complex story; it’s so much more satisfying than the ‘helicobacter – bad’ version, and it’s a much better reflection of the dynamic relationship between humans and the microbes that call us home.

dissecting the predictable (in this case, ffnz on broadbent et al) Alison Campbell May 23

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A paper just out by Broadbent et al (2014) describes research which used data from a 38-year-long longitudinal study of Dunedin children to examine claims that exposure to fluoride in childhood has a negative effect on children’s IQ. The paper found these claims wanting, and thus – quite predictably – it’s now subject to attack by antifluoride activists, both on twitter and via press release.

And so on twitter (among many other scurrilous tweets) we get this: “@JayMan471 @OpenParachute A longitudinal study? This is hilarious. [The] twit has little concept of science.”

Which is hilarious, all right, but only in that it clearly shows that the tweeter has no idea how a longitudinal study works.

And on scoop, a Fluoride Free New Zealand release entitled “Dunedin IQ-fluoride study Sloppy Science”, in which the writer schools peer-review referees in how to do their job.

“Not only were there too few unfluoridated children in this study to give reliable results…”

However, careful statistical analysis overcomes this hurdle – the paper identifies the statistical tools used in their analysis. The FFNZ spokesperson continues:

[It] is likely that they were a large proportion of the 139 children who took fluoride tablets. If so, there is no ‘unfluoridated’ group. Why was this not disclosed?

Probably because a careful reading of the paper shows that this question has been considered by the authors; fluoride tablets had no effect on children’s IQ (nor did other sources of F- in their environment). From the paper:

Residence in a CWF area, use of fluoride dentifrice and intake of 0.5-milligram fluoride tablets were assessed in early life (prior to age 5 years); we assessed IQ repeatedly between ages 7 to 13 years and at age 38 years (Broadbent et al, 2014).

Back to the FFNZ release:

But worse, the study fails to allow for a whole range of confounding factors. The most important period for IQ damage is in the womb, yet the mothers’ fluoride intake and other factors like iodine deficiency were not controlled for.

Well, no:

Preschool fluoride exposure was used in these analyses because this is when brain development is rapid and vulnerable, and thereafter the IQ is known to be relatively stable. Studies of twins indicate that environmental effects on IQ are greatest in the early years, and genetic effects are least during that period (Broadbent et al, 2014).

The charge of not measuring mothers’ fluoride intake, possible iodine deficiency, & so on can also be levelled at the ‘Harvard’ study. A major EU review found many of the various fluoride-IQ studies also evaluated in the Harvard paper to have methodologies with little or no control for various confounding factors such as iodine, lead, & socioeconomic status.

Other confounders in those studies are highlighted by Broadbent et al (2014), who note that these include other environmental sources of fluoride (many of the villages sampled were exposed to F- from industrial exhausts), differences in the size of village populations, proximity to schools and “the lack of relevance of the studies included in the meta-analysis to the use of CWF or fluoride toothpastes” (ibid.).

However, FFNZ’s spokesperson continues:

Similarly, there was poor information on total fluoride intake by these infants. Had the study actually been prospective as claimed, rather than retrospective, this essential information could have been available.

The researchers state – quite explicitly – that fluoride intake was not measured directly.

FFNZ again:

The Dunedin research report begins with the conclusion it set out to “prove” – that fluoridation is harmless. The first two named ‘researchers’ are two of NZ’s leading political promoters of fluoridation. They are dentists, not developmental neurotoxicologists.

The paper by Broadbent and his colleagues (a published, peer-reviewed paper, not just a ‘report’) begins with a statement that is accepted by health authorities the world over: that CWF is cost-effective in reducing dental caries, safe, and environmentally friendly. They did not ‘set out to prove’ this, but to examine the purported link between fluoride exposure and IQ.

In contrast, a Harvard University meta-analysis of studies was conducted by some of the world’s leading expert researchers into developmental neurotoxicology, who have no known bias on fluoridation policy. There were 27 studies reviewed. The total number now available is 43. The Dunedin authors wrongly dismiss this as a single study.

The authors of Broadbent et al correctly point out that the metanalysis by Grandjean & Choi was just that, a single review of a large number of papers. It’s interesting to note at this point that FFNZ is intent on a not-so-subtle attempt to downgrade the paper by Broadbent et al, with the laboured contrast between ‘Harvard University’ and ‘Dunedin’ (rather than Otago University), and the insinuation that because two of the authors of this 2014 paper are “dentists, not developmental neurotoxicologists” they are somehow incapable of performing statistical analyses of data. In fact, every author of the paper holds a PhD ie a research degree – the same qualification as that held by Grandjean and Choi. In addition, FFNZ is really being quite inconsistent here, given that recent TV ads paid for by this advocacy group feature a dentist giving his opinion on the safety of fluoride. I doubt that the individual concerned is a developmental neurotoxicologist either.

FFNZ is also glossing over the fact that the paper has multiple authors from a range of disciplines, not all of whom are faculty members of Otago University (itself an internationally-respected institution), and conveniently ignoring the additional fact that the paper has gone through a rigorous peer review process for an international journal. But let’s go on.

The Harvard review rightly caused concern to decision-makers as it showed a consistent lowering of IQ associated with fluoride intake. It is clearly the reason this Dunedin study has been published – as a political posturing, just as the tobacco companies funded and published ‘research’ showing cigarette smoking did not cause lung cancer.

And what are we missing here? That the “Harvard review” found that IQ was lowered by exposure to fluoride levels much higher than that found in fluoridated water. The authors themselves conceded that their findings did not provide evidence of risk at the levels of fluoride used in community water fluoridation. Regardless of this, FFNZ continues:

The Dunedin IQ-fluoride study is missing just about all the confounding factors that the authors have criticised in the studies reviewed by the Harvard team. This is outright sloppy science. Broadbent criticizes the studies reviewed by Harvard for not controlling for these factors (when in fact some of them did) and then fails to control for them when the data is readily available to him.

Really? How does that fit with statements such as this, for example?

Cohort families represent the full range of socioeconomic status (SES) in the general population of New Zealand’s South Island (Broadbent et al., 2014).

This (says the FFNZ spokesperson) is a single ‘study’ by politically driven dentists against a robust analysis of 27 studies by world-leading experts in this field, from one of the world’s foremost universities. You’d have to have a pretty low IQ to not know whose opinion carries the more credible weight.

No, FFNZ, I’m afraid that your statement above is an example of the logical fallacy known as ‘appeal to authority’. It’s also worth pointing out that 12 months ago the Deans of the Harvard Medical School, School of Dental Medicine and School of Public Health distanced themselves from this study, saying that they

continue to support community water fluoridation as an effective and safe public health measure for people of all ages. Numerous reputable studies over the years have consistently demonstrated that community water fluoridation is safe, effective, and practical. Fluoridation has made an enormous impact on improving the oral health of the American people.

I’ll look forward to seeing a peer-reviewed letter from Fluoride Free NZ to the American Journal of Public Health, critiquing the paper so that their specific criticisms can be replied to by the original authors in the usual way.

 

J.M.Broadbent, W.M.Thomson, S.Ramrakha, T.E.Moffitt, J.Zeng, L.A.Foster Page & R.Poulton (2014) Community Water Fluoridation and Intelligence: Prospective Study in New Zealand. American Journal of Public Health Published online ahead of print May 15, 2014: e1–e5. doi:10.2105/AJPH.2013.301857

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