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Archive for September, 2012

The problem of waning pertussis immunity

There’s been a lot of discussion, both in the scientific literature and online, about recent pertussis outbreaks, which are the worst outbreaks in the US in the last 50 years. How could this possibly be, it is asked, when vaccine uptake for the pertussis vaccine remains high? True, there are pockets of vaccine resistance, where uptake of the vaccine is low, but it’s becoming increasingly clear that, unlike the case of measles outbreaks, low uptake of the pertussis vaccine does not appear to be nearly enough to explain the frequency and magnitude of the outbreaks. Given that it’s been a while since any of us has discussed the recent pertussis outbreak here on SBM, I thought that it would be a good time for me to do so, particularly because there have been some new studies and new developments since April, including a paper hot off the presses last Thursday in the New England Journal of Medicine. As a result, those of you who read me at my not-so-super-secret other blogging location might find some of the material in this post familiar, but given the new NEJM paper, I thought that now would be a good time to synthesize and update what I’ve discussed before in different forums in a more comprehensive way, even at the risk of some repetition of previous material I’ve published elsewhere. Hopefully, it will also provide materials for skeptics and supporters of SBM to counter the antivaccine movement, which has pounced on the recent pertussis outbreaks as evidence that the “vaccine doesn’t work.”

Without a doubt (to me, at least), the biggest difference between science-based doctors and quacks is a very simple one. When a treatment or preventative measure isn’t working as well as it should, we science-based physicians ask why. We try to find out what is not working optimally and why. Then we try to figure out how to make things better. So it is with the acellular pertussis vaccine. This vaccine protects against whooping cough, which is caused by Bordetella pertussis, and is administered to children in the form of a combination vaccine, the DTaP (diptheria/tetanus/acellular pertussis). Five doses are recommended for children, the first at age 2 months, and then at ages 4 months, 6 months, 15-18 months, and 4-6 years. There is also the newer formulation, the Tdap (tetanus, diptheria, and acellular pertussis), which is recommended for people between the ages of 11 and 64. The Tdap is now usually administered first at age 11-12, with additional recommendations for a Tdap booster in adolescents and adults summarized here, here, and here. Unfortunately, although the vaccine works, recent outbreaks have suggested that we need to change our approach to pertussis vaccination. Let’s see why.
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Posted in: Vaccines

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Can we finally just say that acupuncture is nothing more than an elaborate placebo?

I realize that Steve blogged about this study earlier in the week, but since I also commented on this particular study as my not-so-super-secret alter ego, I figured it rated a place on SBM as well. I emphasized different aspects of the study and tried to quantify exactly why, under even the most charitable interpretation of the study possible, the effects are not clinically significant. Besides, if the level of comments and e-mails is any indication, there is sufficient interest in this particular study to rate a second post.

Not suprisingly, this study is about about acupuncture. Well, it’s not exactly a study, it’s a meta-analysis that aggregates a whole lot of acupuncture studies in which this most popular of woos is administered to patients with chronic pain from a variety of causes. It’s also being promoted all over the place with painfully credulous headlines like:
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Posted in: Acupuncture

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Acupuncture: NCCAM Calls California’s Bluff

The [California Department of Consumer Affairs'] use of the term “endorsement” is inaccurate, may confuse the public, and may lead the public to falsely conclude that NIH has made certain efficacy and/or safety conclusions regarding acupuncture. Further, consensus conference reports are not a policy statement of NIH or the Federal Government… NIH asks that you correct these two points of information in your booklet and on your website.

— Jack Killen, MD, Deputy Director, NCCAM, NIH

I have to praise the Deputy Director of the National Center for Complementary and Alternative Medicine (NCCAM), Jack Killen, for asking the State of California to remove a couple of false claims in a “Consumer’s Guide” on acupuncture.

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Posted in: Acupuncture, Traditional Chinese Medicine

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Magnesium: The cure to all disease?

Having spent many evenings and weekends working in a retail pharmacy with a thriving vitamin and supplement aisle, I’m no longer surprised at the purchasing habits of consumers. The setting gave me not only the opportunity to learn about the latest supplement fads, but also to speak with consumers that place great faith in these products. A recent paper suggests 25% of CAM users account for 75% of all expenditures on CAM. And that’s consistent with what I saw in the pharmacy. Some consumers spend hundreds per month on supplements, so the belief that these products are beneficial must be very strong. So I like to ask about reasons for use. Many attribute their current health status to supplements, and usually tell me that their supplements are for preventing disease, optimizing health, or “boosting” the immune system. And while I’m encouraged to see these consumers take an active interest in maximizing their own health, I’m often puzzled by the decision-making that’s occurring. In some cases, beliefs about health, medicine, or the effectiveness of their supplements are misguided, or flat-out wrong. They’re getting expensive urine and positive feelings, but there’s little evidence to suggest the supplementing is having any objective benefits. More surprisingly, some consumers take products for which there is no medical indication at all – it’s intended as “primary prevention” of a medical condition they believe they can avoid through supplement use. Afraid of macular degeneration? Take lutein. Or worried about Alzheimer’s? Grab some ginkgo biloba. No matter your anxiety, there’s a supplement marketed for your. One supplement with enduring popularity is magnesium.  It cures cancer. And depression. Throw away your inhalers, because it cures asthma too. Read enough online, and you’ll conclude that magnesium is quite possibly the prevention and the cure to all disease. (more…)

Posted in: Herbs & Supplements

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An Acupuncture Meta-Analysis

A recent meta-analysis of acupuncture studies for chronic pain by Vickers et al is getting a great deal of press. The authors’ conclusions are:

Acupuncture is effective for the treatment of chronic pain and is therefore a reasonable referral option. Significant differences between true and sham acupuncture indicate that acupuncture is more than a placebo. However, these differences are relatively modest, suggesting that factors in addition to the specific effects of needling are important contributors to the therapeutic effects of acupuncture.

News reports generally reflect this conclusion – acupuncture works, but mostly (although not entirely) through placebo effect, but that’s OK.

I took a close look at the study and find that the authors display considerable pro-acupuncture bias in their analysis and discussion. They clearly want acupuncture to work. That aside, the data are simply not compelling, and the authors, in my opinion, grossly overcall the results, which are compatible with the conclusion that there are no specific effects to acupuncture beyond placebo.

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Posted in: Acupuncture

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Learning from Animals: Evolutionary Medicine with a Twist

In 2005, cardiologist Barbara Natterson-Horowitz was called to the zoo to examine a non-human patient, an emperor tamarin with heart failure.  She was surprised when the veterinarian told her not to look her patient in the eyes because eye contact could cause capture myopathy. In this condition, when an animal is captured, restrained, and feels threatened, there is a catastrophic surge of adrenaline that damages muscle tissues and can kill. It was described decades ago, but medical doctors don’t read the veterinary literature. It wasn’t until the early 2000s that American doctors began to recognize a similar phenomenon in human patients, takotsubo or stress-induced cardiomyopathy.

She began to wonder whether animals got other human diseases. She quickly learned that they did. Jaguars get breast cancer and may carry the same BRCA1 gene that plagues Ashkenazi Jewish women, rhinos get leukemia, penguins get melanoma, gorillas die from ruptured aortas, and koalas are in the midst of an epidemic of sexually transmitted chlamydia.  Wild dragonflies infected with parasites become obese and develop a form of metabolic syndrome. Pretty much every human disorder occurs in animals too.

With the help of writer Kathryn Bowers, she distilled her findings into a book: Zoobiquity: What Animals Can Teach Us About Health and the Science of Healing.  It’s a good read: informative, well argued, spiced with intriguing trivia, and more entertaining than a trip to the zoo. (more…)

Posted in: Book & movie reviews, Evolution, Veterinary medicine

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Is shameless self-promotion of your science a good idea?

As part of my ongoing effort to make sure that I never run out of blogging material, I subscribe to a number of quack e-mail newsletters. In fact, sometimes I think I’ve probably overdone it. Every day, I get several notices and pleas from various wretched hives of scum and quackery, such as NaturalNews.com, Mercola.com, and various antivaccine websites. I think of it as my way of keeping my finger on the pulse of the antiscience and pseudoscience wing of medicine, but I must admit that I don’t really read them all, but they do allow me to know what the quacks are selling and what new arguments they’re coming up with without actually going to each of their websites. I can then judge by the headlines and the blurbs included in the e-mails whether I think it’s worth it to go to the website itself and, of course, whether the topic might represent fodder for a good blog post. I will admit that not all the sites I monitor are as loony as the Health Ranger’s. In fact, I monitor the blogs and websites of the National Center for Complementary and Alternative Medicine (NCCAM), various naturopath organizations, and the like in order to learn of the “respectable” arguments being used to tout various nostrums.
Sometimes—albeit rarely—I even learn about some interesting new science.

One of the most common themes (besides antivaccine hysteria, claims that diet can prevent 95% of all cancers, etc.) tends to be one of a variety of pitches for various “cures” of serious diseases like cancer and heart disease that “they” don’t want you to know about; i.e., the Kevin Trudeau gambit. Who this “they” is can range from doctors to pharmaceutical companies to universities to the government, but the central message is that someone out there doesn’t want you to know The Truth. A variation of this sort of appeal is the claim that there is a promising new therapy, a cure even, usually natural, that is languishing somewhere because it can’t be patented, because pharmaceutical companies would lose money if it were ever validated and brought into clinical use, or because it goes against current medical dogma. It doesn’t even have to be natural. After all, dichloroacetate (DCA) is not exactly “natural.” After it was shown to have promise in animal models, a pesticide salesman named Jim Tassano sold DCA bought from chemical companies to desperate cancer patients from a website that claimed to be selling it only for pets with cancer, a ruse that fooled no one. Yet the “natural treatment” crowd embraced it whole-heartedly because it looked as though sellers of DCA were sticking it to The Man.
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Posted in: Basic Science, Cancer, Clinical Trials

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Guiding Lights

This is, I admit, a content free post. July and August are the sunny days here in the great Pacific Northwest, and rather than spend time in front of the computer, I am outside with the kids. To compound matters, I was on call the labor day weekend (I usually write the first draft the weekend before the posts are due) and was very busy. I am finishing this early on Thursday on an airplane to Vegas. My wife and I are taking our first non-child containing vacation in 19 years while my youngest is on a 4 day school trip. Wander the strip, see a show and enjoy the desert heat as a couple and not a family.

I have not had the time to spend researching a topic, so instead I thought I would ramble on about 2.5 topics that have been on my mind. Writing helps to focus my thoughts. Even though I often have residents on service, I still write daily notes as the act of putting thoughts into words is the best way to clarity thoughts. Next week the kids are back at school and I am sure the rains will start up and I will again have time to go into full research mode. In the meantime feel free to ignore this post.

There is nothing to see here. Move along. (more…)

Posted in: General, Science and Medicine

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The DC as PCP? Revisited

There is a disturbing effort afoot to rebrand chiropractors as primary care physicians, a subject both Harriet Hall and I have discussed in previous posts. Part of this effort includes convincing state legislatures to grant prescription privileges to chiropractors, an effort that succeeded in New Mexico, as reported in a post a couple of years ago. Let’s return to New Mexico and see how that is working out for everyone.

By way of background, in 2008, the New Mexico legislature created a new iteration of chiropractor called “certified advanced practice chiropractic physicians” with the authority to

prescribe, administer and dispense herbal medicine, homeopathic medicines, vitamins, minerals, enzymes, glandular products, naturally derived substances, protomorphogens, live cell products, gerovital, amino acids, dietary supplements, foods for special dietary use, bioidentical hormones, sterile water, sterile saline, sarapin or its generic, caffeine, procaine, oxygen, epinephrine and vapocoolants.

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Posted in: Chiropractic, Legal, Politics and Regulation

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