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Less salt: it’s that simple

It has been known for decades that dietary sodium is significantly associated with hypertension and coronary heart disease.  Despite this knowledge, Americans continue to consume more sodium, most of it coming from processed foods.  Various approaches have been used to help individuals modify their behavior, one of the most popular of which is the DASH diet.  Given what we know, you would think that a low-sodium diet would be especially popular with “alternative” practitioners.  After all, what could be more “natural” than lifestyle modification (a mainstay of real medicine since…well…forever).

But as any clinician knows, it’s much easier to get someone to take something than to eliminate something.  Lifestyle modification is difficult, but achievable to a degree as experience has shown with cholesterol, smoking, and other modifiable risk factors.  A recent study in the New England Journal of Medicine evaluated what the possible effect would be of lowering U.S. sodium consumption to 3g/day.  The authors found that, “Modest reductions in dietary salt could substantially reduce cardiovascular events and medical costs and should be a public health target.”

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Posted in: Science and Medicine

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Being Negative Is Not So Bad

A new study published in PLOS Biology looks at the potential magnitude and effect of publication bias in animal trials. Essentially, the authors conclude that there is a significant file-drawer effect – failure to publish negative studies – with animal studies and this impacts the translation of animal research to human clinical trials.

SBM is greatly concerned with the technology of medical science. On one level, the methods of  individual studies need to be closely analyzed for rigor and bias. But we also go to great pains to dispel the myth that individual studies can tell us much about the practice of medicine.

Reliable conclusions come from interpreting the literature as a whole, and not just individual studies. Further, the whole of the literature is greater than the sum of individual studies – there are patterns and effects in the literature itself that need to be considered.

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Posted in: Science and Medicine

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SBM Live Event – April 17th

A panels of bloggers from SBM will be taking part in the Northeast Conference on Science and Skepticism – NECSS 2010, April 17th beginning 10:00AM in New York.

There will be a 70 minute panel discussion moderated by John Snyder and featuring David Gorski, Kimball Atwood, Val Jones, and myself – Steven Novella. The topic of discussion will be the infiltration of pseudoscience into academic medicine.

This will be part of a full day of science featuring other excellent speakers, including James Randi, D. J. Grothe, Steve Mirsky, George Hrab, and Julia Galef. There will also be a live recording of the wildly popular science podcast, The Skeptics’ Guide to the Universe.

Go to www.NECSScon.org to register.

Posted in: Announcements

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Genetic Testing for Patients on Coumadin

Anticoagulation is advised for patients who have had a blood clot or who are at increased risk of blood clots because of atrial fibrillation, artificial heart valves, or other conditions. Over 30 million prescriptions are written every year in the US for the anticoagulant warfarin, best known under the brand name Coumadin. Originally developed as a rat poison, warfarin has proved very effective in preventing blood clots and saving lives; but too much anticoagulation leads to the opposite problem: bleeding. A high level of Coumadin might prevent a stroke from a blood clot only to cause a stroke from an intracranial bleed. The effect varies from person to person and from day to day depending on things like the amount of vitamin K in the diet and interactions with other medications. It requires careful monitoring with blood tests, and it is tricky because there is a delay between changing the dose and seeing the results.

In his book The Language of Life, Francis Collins predicts that Coumadin will be the first drug for which the so-called Dx-Rx paradigm — a genetic test (Dx) followed by a prescription (Rx) — will enter mainstream medical practice. FDA economists have estimated that by formally integrating genetic testing into routine warfarin therapy, the US alone would avoid 85,000 serious bleeding events and 17,000 strokes annually.
A recent news release from the American College of Cardiology described a paper at their annual meeting reporting a study of

896 people who, shortly after beginning warfarin therapy, gave a blood sample or cheek swab that was analyzed for expression of two genes — CYP2C9 and VKORC1 — that revealed sensitivity to warfarin. People with high sensitivity were put on a reduced dose of warfarin and had frequent blood tests. People with low sensitivity were given a higher dose of warfarin.

During the first six months that they took warfarin, those who underwent genetic testing were 31 percent less likely to be hospitalized for any reason and 29 percent less likely to be hospitalized for bleeding or thromboembolism than were a group that did not have genetic testing.

Epstein said that the cost of the genetic testing — $250 to $400 — would be justified by reduced hospitalization costs.

At this point, I don’t believe this study. I’ll explain why I’m skeptical. (more…)

Posted in: Clinical Trials, Pharmaceuticals

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“Vaccines didn’t save us” (a.k.a. “vaccines don’t work”): Intellectual dishonesty at its most naked

If there’s one thing about the anti-vaccine movement I’ve learned over the last several years, it’s that it’s almost completely immune to evidence, science, and reason. No matter how much evidence is arrayed against it, its spokespeople always finds a way to spin, distort, or misrepresent the evidence to combat it and not have to give up the concept that vaccines cause autism. Not that this is any news to readers of this blog, but it bears repeating often. It also bears repeating and emphasizing examples of just the sort of disingenuous and even outright deceptive techniques used by promoters of anti-vaccine pseudoscience to sow fear and doubt about vaccines among parents. These arguments may seem persuasive to those who have little knowledge about science or epidemiology. Sometimes they even seemed somewhat persuasive to me; that is, at least until I actually took the time to look into them.

One example of such a myth is the claim that “vaccines didn’t save us,” also sometimes going under the claim that “vaccines don’t work.” The anti-vaccine website Vaccine Liberation has a large set of graphs purporting to show that the death rates of several vaccine-preventable diseases, including whooping cough, diptheria, measles, and polio were falling before the vaccines for each disease were introduced. The the article quotes Andrew Weil:
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Posted in: Science and Medicine, Vaccines

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The case of John Lykoudis and peptic ulcer disease revisited: Crank or visionary?

One of the themes of SBM has been, since the very beginning, how the paradigm of evidence-based medicine discounts plausibility (or, perhaps more appropriately, implausibility) when evaluating whether or not a given therapy works. One of our favorite examples is homeopathy, a therapy that is so implausible on a strictly scientific basis that, for it to work, huge swaths of well-established science supported by equally huge amounts of experimental and observational evidence would have to be found to be all in serious error. While such an occurrence is not per se impossible, it is incredibly unlikely. Moreover, for scientists actually to start to doubt our understanding of chemistry, biochemistry, pharmacology, and physics to the point of thinking that our understanding of them is in such serious error that homeopathy is a valid description of reality, it would take a lot more than a bunch of low-quality or equivocal studies that show no effect due to homeopathy detectably greater than placebo.

On Friday, Kim Atwood undertook an excellent discussion of this very issue. What really caught my attention, though, was how he educated me about a bit of medical history of which I had been completely unaware. Specifically, Kim discussed the strange case of John Lykoudis, a physician in Greece who may have discovered the etiology of peptic ulcer disease (PUD) due to H. pylori more than a quarter century before Barry Marshall and Robin Warren discovered the bacterial etiology of PUD in 1984. One reason that this story intrigued me is the same reason that it intrigued Kimball. Lykoudis’ story very much resembles that of many quacks, in particular Nicholas Gonzalez, in that he claimed results far better than what medicine could produce at the time, fought relentlessly to try to prove his ideas to the medical authorities in Greece at the time, and ultimately failed to do so. Despite his failure, however, he had a very large and loyal following of patients who fervently believed in his methods. The twist on a familiar story, however, is that Lykoudis may very well have been right and have discovered a real, effective treatment long before his time.
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Posted in: Basic Science, Clinical Trials, Science and Medicine

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Brief Note: Followup on Spinal Decompression Machines

In September 2008 I wrote a post on Misleading Ads for Back Pain Treatment. with particular attention to the bogus claims for the DRX 9000.

The Canadian Broadcasting Company (CBC) show “Marketplace” has just done a scathing exposé of so-called nonsurgical spinal decompression treatment with machines like the DRX 9000 and of some of the unscrupulous practitioners who offer it.  Between the hidden camera footage and the weasel words of the chiropractor they interview, it’s quite entertaining.

Posted in: Chiropractic, Health Fraud

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H. Pylori, Plausibility, and Greek Tragedy: the Quirky Case of Dr. John Lykoudis

Mark Crislip is on vacation, but through an arduous series of shakings and succussions (beating his head against the wall?) we have channeled part of his essence: This post mostly concerns itself with infectious diseases, thanks to several recent posts on SBM that discussed the plausibility of health claims† and that touched on the recent discovery that most peptic ulcer disease (PUD) is caused by a bacterium, Helicobacter pylori. Several comments and statements quoted in those posts reveal recurrent questions regarding both plausibility itself and the history of the H. pylori hypothesis. In this post I’ll attempt to answer some of those questions, but I’ll also insert some new confusion.

Plausibility ≠ Knowing the Mechanism

Let’s first dispense with a simple misunderstanding: We, by which I mean We Supreme Arbiters of Plausibility (We SAPs) here at SBM, do not require knowing the mechanism of some putative effect in order to deem it plausible. This seems so obvious that it ought not be necessary to repeat it over and over again, and yet the topic can’t be broached without some nebbishy South Park do-gooder chanting a litany of “just because you don’t know how it works doesn’t mean it can’t work,” as if that were a compelling or even relevant rebuttal. Let’s get this straight once and for all: IT ISN’T.

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Posted in: Basic Science, History, Science and Medicine

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Vaccinations and autism: are we number 1?

It has been alleged by Great Minds such as Jenny McCarthy that the US recommends far more vaccinations than other countries.  Her precise statement was, “How come many other countries give their kids one-third as many shots as we do?” She put this into the context of wondering if our current vaccine schedule should be less rigid.  The entire piece was filled with what could charitably called less-than-truthful assertions, but examining simply this one assertion might be useful.  Dr. John Snyder has an excellent analysis of the most important assertion, that of the possible benefits of an “alternative vaccination schedule”  which I would encourage you to read.

First, we need to parse out this “more shots than everyone else” statement.  Some countries–Haiti, for example–give far fewer vaccines due not to fewer recommendations but to adverse economic conditions. Because of this, they have very high rates of vaccine-preventable diseases.  They want to vaccinate more, but can’t.  Then there are countries who can afford to vaccinate. Let’s look at what three industrialized nations recommend before six years of age.

Vaccinations, by disease and country, 0-6 years of age

Vaccine France Germany USA Iceland
Hepatitis B Yes Yes Yes No
Rotavirus No No Yes No
Diphtheria, tetanus, and pertusis Yes Yes Yes Yes
Hib Yes Yes Yes Yes
Pneumococcus Yes Yes Yes No
Polio Yes Yes Yes Yes
Influenza Not reported Not reported Yes No
Meales, mumps, rubella Yes Yes Yes Yes
Varicella No Yes Yes No
Hepatitis A No No Yes No
BCG (disseminated TB) Yes No No No
Meningococcus No Yes For some Yes

The chart, as I’ve presented it, is somewhat imprecise.  Some vaccinations are given in a single shot, others in multiple shots, but these generally represent the childhood vaccinations in each country, and the links provided will take you to the more detailed information.

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Posted in: Science and Medicine, Science and the Media, Vaccines

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Placebo Effects Revisited

In the Wall Street Journal last week was a particularly bad article by Melinda Beck about acupuncture. While there was token skepticism (by Edzard Ernst, of course, who is the media’s go-to expert for CAM), the article credulously reported the marketing hype of acupuncture proponents.

Toward the end of the article Beck admits that “some critics” claim that acupuncture provides nothing more than a placebo effect, but this was followed by the usual canard:

“I don’t see any disconnect between how acupuncture works and how a placebo works,” says radiologist Vitaly Napadow at the Martinos center. “The body knows how to heal itself. That’s what a placebo does, too.”

That is a bold claim, and very common among CAM proponents, especially acupuncturists. As the data increasingly shows that acupuncture (and other implausible treatments) provides no benefit beyond placebo, we hear the special pleading that placebos work also.

But is that true? It turns out there is a literature on the placebo effect itself, and the evidence suggests that placebos generally do not work.

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Posted in: Acupuncture, Homeopathy, Science and Medicine

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