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Archive for 2010

Freeways, autism, and correlation versus causation

I have a love-hate relationship with epidemiology.

On the one hand, I love how epidemiology can look for correlations in huge sample sizes, sample sizes far larger than any that we could ever have access to in clinical trials, randomized or other. I love the ability of epidemiology to generate hypotheses that can be tested in the laboratory and then later in clinical trials. Also, let’s not forget that epidemiology is sometimes the only tool available to us that can answer some questions. Such questions generally involve hypotheses that can’t be tested in a randomized clinical trial because of either ethical concerns or others. A good example of this is the question of whether vaccines cause autism. For obvious ethical reasons, it’s not permissible to perform a randomized clinical trial in which one group of children is vaccinated and one is not, and then outcomes with respect to neurodevelopmental outcomes, such as autism and autism spectrum disorders, are tracked in the two groups. The ethical concern with such a study, of course, is the potential harm that would be likely to come to the unvaccinated control group, children who would be left unprotected against common and postentially deadly communicable diaseases.

On the other hand, epidemiology is one of the messiest of sciences, and epidemiological studies are among the most difficult in all of science to perform truly rigorously. The number of factors that can confound are truly amazing, and as a result, it’s very, very easy for an epidemiological study to detect apparent correlations that are either spurious or appear much stronger than the “true” correlation. There can be confounding factors beneath confounding factors wrapped in more confounding factors, the relationships among which are not always apparent. Not infrequently, a condition can appear to be correlated with, for instance, an environmental factor, but in reality that environmental factor and the condition both correlate with a third, unknown confounder. Worse, epidemiologists know that correlation does not necessarily equal causation, but the general public, for the most part, does not, which is why, when anti-vaccine activists, for instance, point out to a rising autism prevalence and then point out that autism prevalence started rising around the same time the vaccine schedule was expanded, to the average layperson the argument sounds compelling. As a result, the design of an epidemiological study is paramount in order to account for or minimize such factors. That’s why I always said I can’t be an epidemiologist. Even though I was very good at math in college, the statistics still made my brain hurt, and I don’t have the patience for the messiness of trying to account for all the possible confounding factors.

However, for all their strengths and flaws, epidemiological studies are an integral part of science-based medicine. They are used to identify predisposing factors to diseases and conditions, environmental contributors to disease, and adverse reactions to drugs, among many other useful pieces of data. That’s why, from time to time, I like to examine epidemiological studies, particularly if they’re epidemiological studies that are getting a lot of press.

The use and abuse of autism epidemiology studies

For instance, studies like this one described in a story in the Los Angeles Times on Friday entitled Proximity to freeways increases autism risk, study finds: More research is needed, but the report suggests air pollution could be a factor:
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Posted in: Epidemiology, Neuroscience/Mental Health, Public Health, Vaccines

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For Good Reason…

This one crept up on me by surprise. You see, I recorded an interview with D.J. Grothe, President of the James Randi Educational Foundation and host of the podcast For Good Reason back in November. I wasn’t sure when it would appear. Well, it turns out that it popped up on my iTunes podcast feeds sometime over the last few days. (It’s been really busy at work, and I haven’t really been paying attention to podcasts–at least, not until yesterday.)

So, here it is. I haven’t listened to it all yet, but hopefully I explained myself well enough and did credit to my fellow SBM bloggers. DJ is a good interviewer, which means he presses his subjects a bit and sometimes gets them out of their comfort zone.

Posted in: Science and Medicine

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Ososillyococcinum and other Flu bits.

Osillococcinum

I keep half an eye on the medicine displays in stores when I shop, and this year is the first time I have seen Oscillococcinum being sold.  Airborne as been a standard for years, but Airborne has been joined by Oscillococcinum on the shelves.  Dumb and dumber.    It may be a bad case of confirmation bias, but it seems I am seeing more  iocane powder, I mean oscillococcinum, at the stores.

On a recent podcast I was listening to one of the hosts suggested a homeopathic remedy for flu symptoms, and then specifically suggested osillococcinum.  This is a technology podcast, the 404, and the hosts are certainly bright, educated people.  Why would he suggest osillococcinum?  Probably because he unaware of how oh so silly the product is.

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Posted in: Homeopathy, Pharmaceuticals, Vaccines

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California Forbids Chinese Bloodletting

In November 2010, the California Department of Consumer Affairs (DCA) finally decided to act responsibly and forbid the prevalent practice of Chinese bloodletting by licensed acupuncturists.

The practice became a concern for the DCA when allegations of unsanitary bloodletting at a California (CA) acupuncture school surfaced.

The incident allegedly occurred during a “doctoral” course for licensed practitioners. The instructor was reportedly demonstrating advanced needling and bloodletting techniques. During the process, he took an arrow-like lancing instrument that is called a “three-edged needle” (三棱针), sharpened it with sandpaper, cleaned it with alcohol, and then asked a student-volunteer to roll a towel around his neck (similar to what is depicted in Image 1). The instructor then cleaned the student’s temporal region with alcohol, and punctured a superficial blood vessel with the arrow-like instrument. The student then held his head over the garbage can, gushing blood for a while.

Images 1 & 2. Chinese bloodletting. Image 1 shows a technique used to bleed the head or the face, where a towel is rolled around the neck to control the arterial pressure. Image 2 shows the practice of “wet cupping.”

The ancient practice of bloodletting, with or without cupping, is still widely used in Chinese medicine to remove “stagnant blood, expel heat, treat high fever, loss of consciousness, convulsion, and pain.”1 The amount of blood let depends on the condition, and the location of the incision. A contemporary book recommends letting a tiny amount from a point adjacent to the thumbnail for a condition described as “wind-heat invasion” of the lung. The symptoms associated with this unscientific nomenclature include chills and fever, sore throat, stuffy or runny nose, and a yellow discharge,2 which could correspond to many respiratory conditions, including the common cold, influenza, pneumonia, etc.
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Posted in: Acupuncture, Public Health, Science and Medicine

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CAM and the Law Part 4: Regulation of Supplements and Homeopathic Remedies

Another major set of legal standards that apply to alternative medicine are the laws and regulations that govern the manufacturing and availability of homeopathic and herbal remedies and dietary supplements. Although there is less ambiguity in these standards than in some of the areas I’ve covered previously, there are certainly loopholes aplenty available to avoid the need for any truly scientific standards of evaluating safety and efficacy. This is perhaps the area in which the triumph of politics over science is most vivid.

Regulation of Homeopathic Remedies

The Food and Drug Administration was constituted as the agency responsible for regulating medicines and most foods by the Food, Drug, and Cosmetic Act (FDCA) of 1938. The FDCA has been updated and amended in various ways since then, but it is still the primary law governing the regulation of prescription and non-prescription substances used to treat illness. The law identifies substances acceptable for sale as medicines as those listed in its official compendia, the United States Pharmacopeia-National Formulary (USP-NF) and the Homeopathic Pharmacopeia of the United States (HPUS). The HPUS was a list of homeopathic remedies first published by the American Institute of Homeopathy, a professional body for homeopaths, in 1897 and now published and maintained by the Homeopathic Pharmacopoeia Convention of the United States (HPCUS), an independent organization of homeopathic “experts.” The inclusion of homeopathic remedies as accepted drugs in the original legislation was primarily due to the efforts of Senator Royal Copeland, a physician trained in homeopathy and one of the principle authors of the FDCA.1
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Posted in: Homeopathy, Legal, Science and Medicine

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Acupuncture and the Hazard of Nonsense

A recent study published in the Archives of Opthalmology compare patching of one eye vs acupuncture in the treatment of amblyopia in older children, and finds positive results from acupuncture. The study, and its press, are a good example of the hazards of studying highly implausible modalities.

First let’s dissect the study itself – from the abstract:

In a single-center randomized controlled trial, 88 eligible children with an amblyopic eye who had a best spectacle-corrected visual acuity (BSCVA) of 0.3 to 0.8 logMAR at baseline were randomly assigned to receive 2 hours of patching of the sound eye daily or 5 sessions of acupuncture weekly. All participants in our study received constant optical correction, plus 1 hour of near-vision activities daily, and were followed up at weeks 5, 10, 15, and 25. The main outcome measure was BSCVA in the amblyopic eye at 15 weeks.

For background, amblyopia occurs when the brain tends to ignore visual information from one eye. This results from a variety of causes, but commonly from the two eyes having different refractive errors (anisometropic) – one eye may be more near-sighted or far-sighted than the other. The brain cannot combine information from both eyes, so it ignores one. This can be corrected in younger children, up to age 7, by correcting the vision for the refractive problems. If visual correction alone is not enough, then patching one eye (the strong eye) to force the brain to use the weak eye can be effective. This is usually done for only 2 hours a day, otherwise amblyopia of the patched eye can occur.

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Posted in: Acupuncture

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Integrative Medicine is the Butt of a Sokal-Type Hoax

In 1996, Alan Sokal got a bogus paper published in the journal Social Text. It was a parody full of meaningless statements in the jargon of postmodern philosophy and cultural studies. The editors couldn’t tell the difference between Sokal’s nonsense and the usual articles they publish.

Now a British professor of medical education, Dr. John McLachlan, has perpetrated a similar hoax on supporters of so-called “integrative” medicine. He reports his prank in an article in the British Medical Journal (BMJ).  

After receiving an invitation to submit papers to an International Conference on Integrative Medicine, he invented a ridiculous story about a new form of reflexology and acupuncture with points represented by a homunculus map on the buttocks. He claimed to have done studies showing that

responses are stronger and of more therapeutic value than those of auricular or conventional reflexology. In some cases, the map can be used for diagnostic purposes.

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Posted in: Humor

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The “decline effect”: Is it a real decline or just science correcting itself?

‘Tis the season, it would seem, for questioning the scientific method.

You might recall that back in October, I was a bit miffed by an article in The Atlantic entitled Lies, Damned Lies, and Medical Science and expressed my annoyance in one of my typical logorrheic posts. Then, a mere couple of weeks later, Steve Simon wrote a rather scathing criticism of the very concept of science-based medicine, which I ended up answering, again in my usual inimitable logorrheic fashion. Unfortunately, these things often come in threes. Well, maybe not always threes. It’s not as though this “rule” is anything like the count for the Holy Hand Grenade of Antioch, where “Four shalt thou not count, nor either count thou two, excepting that thou then proceed to three. Five is right out.” Except that five isn’t always right out when it comes to these sorts of criticisms of science and/or science-based medicine.

But enough of my pathetic attempt to channel Mark Crislip. The third count in articles expressing skepticism of the scientific method and science-based medicine comes, for purposes of my discussion, in the form of an article in The New Yorker by Jonah Lehrer entitled The Truth Wears Off: Is There Something Wrong With the Scientific Method? Unfortunately, the full article is restricted only to subscribers. Fortunately, a reader sent me a PDF of the article; otherwise, I wouldn’t have bothered to discuss it. Also, Lehrer himself has elaborated a bit on questions asked of him since the article’s publication and published fairly sizable excerpts from his article here and here. In any case, I’ll try to quote as much of the article as I think I can get away with without violating fair use, and those of you who don’t have a subscription to The New Yorker might just have to trust my characterization of the rest. It’s not an ideal situation, but it’s what I have to work with.
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Posted in: Clinical Trials, Science and Medicine, Science and the Media

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Of SBM and EBM Redux. Part II: Is it a Good Idea to test Highly Implausible Health Claims?

Review

This is the second post in a series* prompted by an essay by statistician Stephen Simon, who argued that Evidence-Based Medicine (EBM) is not lacking in the ways that we at Science-Based Medicine have argued. David Gorski responded here, and Prof. Simon responded to Dr. Gorski here. Between that response and the comments following Dr. Gorski’s post it became clear to me that a new round of discussion would be worth the effort.

Part I of this series provided ample evidence for EBM’s “scientific blind spot”: the EBM Levels of Evidence scheme and EBM’s most conspicuous exponents consistently fail to consider all of the evidence relevant to efficacy claims, choosing instead to rely almost exclusively on randomized, controlled trials (RCTs). The several quoted Cochrane abstracts, regarding homeopathy and Laetrile, suggest that in the EBM lexicon, “evidence” and “RCTs” are almost synonymous. Yet basic science or preliminary clinical studies provide evidence sufficient to refute some health claims (e.g., homeopathy and Laetrile), particularly those emanating from the social movement known by the euphemism “CAM.”

It’s remarkable to consider just how unremarkable that last sentence ought to be. EBM’s founders understood the proper role of the rigorous clinical trial: to be the final arbiter of any claim that had already demonstrated promise by all other criteria—basic science, animal studies, legitimate case series, small controlled trials, “expert opinion,” whatever (but not inexpert opinion). EBM’s founders knew that such pieces of evidence, promising though they may be, are insufficient because they “routinely lead to false positive conclusions about efficacy.” They must have assumed, even if they felt no need to articulate it, that claims lacking such promise were not part of the discussion. Nevertheless, the obvious point was somehow lost in the subsequent formalization of EBM methods, and seems to have been entirely forgotten just when it ought to have resurfaced: during the conception of the Center for Evidence-Based Medicine’s Introduction to Evidence-Based Complementary Medicine.

Thus, in 2000, the American Heart Journal (AHJ) could publish an unchallenged editorial arguing that Na2EDTA chelation “therapy” could not be ruled out as efficacious for atherosclerotic cardiovascular disease because it hadn’t yet been subjected to any large RCTs—never mind that there had been several small ones, and abundant additional evidence from basic science, case studies, and legal documents, all demonstrating that the treatment is both useless and dangerous. The well-powered RCT had somehow been transformed, for practical purposes, from the final arbiter of efficacy to the only arbiter. If preliminary evidence was no longer to have practical consequences, why bother with it at all? This was surely an example of what Prof. Simon calls “Poorly Implemented Evidence Based Medicine,” but one that was also implemented by the very EBM experts who ought to have recognized the fallacy.

There will be more evidence for these assertions as we proceed, but the main thrust of Part II is to begin to respond to this statement from Prof. Simon: “There is some societal value in testing therapies that are in wide use, even though there is no scientifically valid reason to believe that those therapies work.”

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Posted in: Chiropractic, Clinical Trials, Energy Medicine, Health Fraud, History, Homeopathy, Medical Academia, Medical Ethics, Naturopathy, Politics and Regulation, Science and Medicine

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Good Idea, Bad Execution: Dosing Errors, A Preventable Harm

We spend a lot time at SBM discussing different elements of the art and science of medicine, and how we believe that practice can be improve. Yet our science-based intentions can be thwarted at the last possible moment – in the form of dosing errors. The workup may have been comprehensive, the diagnosis could be correct, the most clinically and cost-effective intervention chosen, and whammo. An overdose or underdose, possible toxicity, and a failure to achieve the desired outcome. It’s a completely avoidable, but often overlooked aspect of the practice of medicine.

In my last post, I noted how cough and cold products for children have largely been withdrawn from the market due to their lack of efficacy, and the risks related to toxicity. Today’s post is going to dive a little more deeply into factors that can contribute to toxicity in the pediatric population. Let’s start with a vignette that may be familiar to parents:

The new father is wakened from a blissful, deep sleep by a crying child. Once Dad realizes when and where he is, and the source of the crying, he silently curses the short duration of action of the acetaminophen liquid he gave his child at bedtime. It has probably worn off already, and the fever is back.  Stumbling into his child’s room in the dark, he can feel the heat radiating off his body.  He fumbles around for the Tylenol, and something to measure it with. He can’t find the dropper bottle, but finds a bottle of syrup. It’s hard to measure the dose in the dark, and the medicine cup he finds is hard to read. “I think the dose is a teaspoon..that’s 5mL”.  He pours the medicine into his child’s throat, tucks him back into bed, and both are back asleep within minutes.

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Posted in: Science and Medicine

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