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Archive for November 13th, 2008

Vitamin Cocktail with a Meme Twist (Supplement my gimlet with a dash of dissonance)

A trail of recent reports is trying to tell us something. But are we listening, and are “they” listening? If so, does it mean the same to “them” as it does to us?

The report trail is telling us that multiple vitamins fail as preventatives against cardiovascular disease, cancer, or even for anything other than for dietary vitamin deficiency. And that is what we were saying in the first place – forty and more years ago.

Here is a partial list of these recent reports –  followed by an odd turn

Vitamins E and C were ineffective in preventing `cardiovascular disease in men. Sesso HD, Buring JE, Christen WG et al. JAMA, 2008;300 (Physicians’ Health Study II, mong 14,641 male physicians. [...] The study participants were randomized to receive 400 IU of vitamin E every other day or a placebo and 500 mg of vitamin C daily or a placebo.

B Vitamins (B12, B6, folate) May Not Reduce Cardiovascular Events For Coronary Artery Disease Patients Ebbing M, et al, JAMA 2008, Aug 20 — In a large clinical trial involving patients with coronary artery disease, use of B vitamins B6, B12, folate was not effective for preventing death or cardiovascular events. Patients were randomly assigned to one of four groups receiving a daily oral dose of one of the following treatments: folic acid, 0.8mg, plus vitamin B12 , 0.4mg, plus vitamin B6 , 40mg (n= 772); folic acid plus vitamin B12 (n = 772); vitamin B6 alone (n = 772); or placebo (n = 780).The study was stopped early because of concerns among the participants about preliminary results from another similar Norwegian study suggesting no benefits from the treatment and an increased risk of cancer from the B vitamins. Daily supplementation combination that included folic acid and vitamin B6 and B12 had no significant effect on the overall risk of cancer, including breast cancer, among women at high risk of cardiovascular disease. Zhang M et al, JAMA 2008 Nov. 5.

Certain Vitamin Supplements May Increase Lung Cancer Risk, Especially In Smokers. November 11, 2008, from American Thoracic Society. March of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

Selenium and vitamin E supplements, taken either alone or together, did not prevent prostate cancer; these results came from initial, independent review of study data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT), funded by the National Cancer Institute. (publication  Feb. 1 in the Journal of Clinical Oncology.)

These reports, along with those showing inefficacy of vitamin E in CV prevention and others, all in recent months, dovetail on more reported over the past decade. Now for the dissonance. A popular Web portal posted a brief questionnaire following one of last week’s reports. It asked readers to answer if they took vitamins regularly, infrequently, or not at all.
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Posted in: Cancer, Clinical Trials, Health Fraud, Herbs & Supplements, Nutrition, Politics and Regulation

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Bad Science: Four Things I Learned From Dr. Ben Goldacre

“You cannot reason people out of positions they didn’t reason themselves into.”

– Ben Goldacre, MD

Dr. Ben Goldacre is the author of the popular Guardian column, Bad Science. He has recently published a book by the same name. Bad Science received a very favorable review from the British Medical Journal and although I was tempted to write my own review for Science Based Medicine, I decided to cherry pick some concepts from the book instead. I hope you’ll enjoy the cherries.

Honesty & Placebos

As you can imagine, any good book about bad science must devote at least one chapter to the concept of placebos. We are all quite familiar with placebos, and how squarely the vast majority (and some would argue all) of complementary and alternative medicines fit into that category.  Ben surprised me with a couple of points that I hadn’t considered previously. Firstly, that alerting patients to the fact that you’re planning to prescribe them a placebo does not necessarily negate its effects, and secondly that no matter how skeptical or intelligent you are – all humans are subject to placebo effects.

Ben references a 1965 study from Johns Hopkins [Park et al., Archives of General Psychiatry] in which patients were explicitly told that they were going to receive a sugar pill (with no medicine in it at all) as treatment for their neuroses. The researchers reported substantial improvements in many of the study subjects’ symptoms.

This is the script that the physicians were to use to explain the placebos to the study subjects:

Mr. Doe… we have a week between now and your next appointment, and we would like to do something to give you some relief from your symptoms. Many different kinds of tranquilizers and similar pills have been used for conditions such as yours, and many of them have helped. Many people with your kind of condition have also been helped by what are sometimes called ‘sugar pills,’ and we feel that a so-called sugar pill may help you too. Do you know what a sugar pill is? A sugar pill is a pill with no medicine in it at all. I think this pill will help you as it has helped so many others. Are you willing to try this pill?

Wow. I was under the impression that the efficacy of the placebo was in the person’s belief that it was a legitimate medicine/therapy. Perhaps it only matters that the prescribing physician believes it might help? Perhaps snake oil salesmen are wasting their time on linguistic and pseudoscientific mental gymnastics?

Of course, the “gymnastics” do help. Other research has shown that the more complex the associated placebo ritual, the more potent its effects (such as piercing the skin with fine needles in many different locations). Nonetheless, I was surprised that an honest and accurate description of a placebo does not necessarily negate its effects.
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Posted in: Book & movie reviews, General, Herbs & Supplements, Science and the Media

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