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Archive for Science and Medicine

An Influenza Recap: The End of the Second Wave

We are nearing the end of the second wave of the 2009 H1N1 pandemic, and are now a few months out from the release of the vaccine directed against it.  Two topics have dominated the conversation: the safety of the 2009 H1N1 influenza vaccine, and the actual severity of the 2009 H1N1 infection.  Considering the amount of attention SBM has paid the pandemic and its surrounding issues, and in light of a couple of studies just released, it seems time for an update.

2009 H1N1 Vaccine Safety

This week the CDC released a report that evaluated the safety record of the 2009 H1N1 vaccine.  The first two months of the vaccine’s use were examined, from October 1st through November 24th using data from two of the larger surveillance systems monitoring the 2009 H1N1 vaccine’s safety: the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD).  This report represents the largest, and to date best, evaluation of the 2009 H1N1 vaccine’s safety profile since its initial testing and release.  The findings are reassuring.

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

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Evidence in Medicine: Experimental Studies

Several weeks ago I wrote the first in a brief series of posts discussing the different types of evidence used in medicine. In that post I discussed the role of correlation in determining cause and effect.

In this post I will discuss the basic features of an experimental study, which can sere as a check-list in evaluating the quality of a clinical trial.

Medical studies can be divided into two main categories – pre-clinical or basic science studies, and clinical studies. Basic science studies involve looking at how parts of the biological system work and how they can be manipulated. They typically involve so-called in vitro studies (literally in glass) – using test tubes, petri dishes, genetic sequencers, etc. Or they can involve animal studies.

Clinical trials involve people. They are further divided into two main categories – observational studies and experimental studies. I will be discussing experimental studies in this post – studies in which an intervention is done to study subjects. Observational studies, on the other hand, look at what is happening or what has happened in the world, but does not involve any intervention.

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Posted in: Science and Medicine

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Endocrine disruptors—the one true cause?

A common theme in alternative medicine is the “One True Cause of All Disease”. Aside from the pitiable naivete, it’s implausible that “acidic diet”, liver flukes, colonic debris, the Lyme spirochete, or any other problem—real or imagined—can cause “all disease” (in addition to the fact that most of these ideas are intrinsically mutually exclusive).

One of the popular new ideas in this category is that of “endocrine disrupting chemicals” (EDCs). These are chemicals in the environment that physiologically or chemically mimic naturally occurring human hormones. That some environmental substances are chemically similar to human hormones is indisputable. That these substances can have a real physiologic effect in vitro seems to hold up. How much of an effect these chemicals may have in real human populations is an open question.

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Posted in: Science and Medicine, Science and the Media

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Lose those holiday pounds

Lose weight without diet or exercise? I guess that leaves cancer.

–David Letterman.

It is the day after Thanksgiving, and I have probably eaten enough calories to support the average family for at least three days. I am hesitant to comment on what my actual weight may be, but others have not been so reticent about discussing my appearance over at RDCT. At least I am not female; then I would get no end of critiques based on my looks.

Now that I am up a few holiday pounds, it would be nice to lose some weight. Of course I do not want to do it the old fashioned way, with diet and exercise. Diet and exercise take time and are fundamentally painful. I want to eat what I want when I want from the comfort of my Lazy Boy. I want an easy way to lose weight. The interwebs, as is often the case, have been kind enough to provide me with numerous emails suggesting all sorts of simple ways to alter my physique for the better, some of which even include weight loss.

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Posted in: Science and Medicine

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A temporary reprieve from legislative madness

While doctor visits for influenza-like illnesses seem to be trending downward again, and ”swine flu” is becoming old news, I’d like to draw attention to an H1N1 story that has received very little coverage by the mainstream media.

Doctors in several states can now protect their most vulnerable patients from the H1N1 virus without worrying about breaking the law. In order to save lives, several states have announced emergency waivers of their own inane public health laws, which ban the use of thimerosal-containing vaccines for pregnant women and young children.

Legislators in California, New York, Illinois, Missouri, Iowa, Delaware, and Washington state have enacted these science-ignoring laws in response to pressures from the anti-vaccine lobby and fear-struck constituents. Except for minor differences, each state’s law is essentially the same, so I will focus on the one from my state of New York.

New York State Public Health Law §2112 became effective on July 1, 2008. It prohibits the administration of vaccines containing more than trace amounts of thimerosal to woman who know they are pregnant, and to children under the age of 3. The term “trace amounts” is defined by this law as 0.625 micrograms of mercury per 0.25 mL dose of influenza vaccine for children under 3, or 0.5 micrograms per 0.5 mL dose of all other vaccines for children under 3 and pregnant women. Because thimerosal (and thus, mercury) exists only in multi-dose vials of the influenza vaccines (both seasonal and novel H1N1), this law really only applies to these vaccines. The mercury concentration of the influenza vaccines is 25 micrograms per 0.5 mL, which therefore makes their use illegal. Unfortunately, the only form of the H1N1 vaccine initially distributed, and that could be used for young children and pregnant women, was the thimerosal-containing form. The thimerosal-free vaccine was the last to ship, and in low supply, and the nasal spray is a live-virus vaccine, not approved for use in pregnancy or children under 2. That meant, without a waiver of the thimerosal ban, these groups could not be vaccinated.
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Posted in: Politics and Regulation, Public Health, Science and Medicine, Vaccines

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Ontario naturopathic prescribing proposal is bad medicine

Two weeks ago, Canadian Skeptics United published on their Skeptic North site a piece by an Ontario pharmacist criticizing a proposal by the province to grant limited prescribing rights to naturopaths. The essay, which was reprinted in the National Post on Tuesday, outlines the intellectual and practical conundrum presented by allowing those with education that diverges from science-based practices to prescribe drugs.

The naturopath lobby came out in force and was relatively unopposed in the 54 comments that followed, primarily because the NP closes comments 24 hours after online posting. Therefore, those with a more rational and considered viewpoint based in facts were locked out from commenting. This is quite disappointing to me personally and professionally because of the wildly emotional appeals, strawman arguments, and smears and attacks on the author himself without, of course, addressing his well-founded criticism of the prescribing proposal before the provincial government.

At the Skeptic North post, the piece even drew a naturopath who equated the criticism of his/her field with the Nazis and Mussolini. However, you can’t write critiques of these practices without attracting attacks ad hominem, especially Godwin’s Law, that are the resort of those whose arguments are logically flawed.
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Posted in: Science and Medicine

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Why Universal Hepatitis B Vaccination Isn’t Quite Universal

I am just a parent with some questions about vaccine safety and was happy to find your website.  I have noticed that the Scandinavian countries do not routinely recommend HepB vaccination unless the mother is a known carrier.  I did not see this addressed anywhere on your website and I hope you or one of your colleagues might consider discussing the reasons that some advanced countries are not routinely giving this particular vaccine. Thank you.”

Vaccination is a complicated and at times confusing topic that generates a large number of quite reasonable questions by parents like the one above.  At the same time, the ever-wandering aim of the anti-vaccinationist movement appears once again to be falling on the vaccine against Hepatitis B, and I’ve heard them pose this very question with the intent of sowing doubt in the current vaccination schedule.  Regardless of the source, this question is clearly on the mind of some parents, and I am happy to answer it.

As usual, this question has quite a bit to parse out.  I think it may be most helpful to examine why we vaccinate against Hepatitis B the way we do in the US, how most countries in the world approach the problem, and finally examine the reason why eight European countries do not universally vaccinate against HBV.  First things first though: what is Hepatitis B?

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Posted in: Public Health, Science and Medicine, Vaccines

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Does C-section increase the rate of neonatal death?

It is a potentially devastating indictment of the rising C-section rate. Most midwifery and “natural” childbirth websites claim that elective C-section triples the rate of neonatal mortality. Mainstream web sites like Feministing.com, and newspapers like The New York Times have repeated the claim. There’s just one problem. It’s not true.

The claim originated with the paper Infant and Neonatal Mortality for Primary Cesarean and Vaginal Births to Women with “No Indicated Risk,” United States, 1998–2001 Birth Cohorts, MacDorman et al, Birth Volume 33 Page 175, September 2006. According to the authors:

Neonatal mortality rates were higher among infants delivered by cesarean section (1.77 per 1,000 live births) than for those delivered vaginally (0.62). The magnitude of this difference was reduced only moderately on statistical adjustment for demographic and medical factors, and when deaths due to congenital malformations and events with Apgar scores less than 4 were excluded. The cesarean/vaginal mortality differential was widespread, and not confined to a few causes of death. Conclusions: Understanding the causes of these differentials is important, given the rapid growth in the number of primary cesareans without a reported medical indication.

The implication, of course, is C-sections done without a medical indication raises the risk of neonatal death by a factor of three. The entire study hinges on a critical detail. Are women with “no indicated risk” really women who have no risk factors? The answer is a resounding no.

Since birth certificates are such an important source for research information, they have been repeatedly studied for accuracy. Birth certificates are highly accurate for administrative data like parents’ names or numerical data like weight or Apgar scores. It is well known, however, that they are highly inaccurate when it comes to listing complications.
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Recombinant Human Antithrombin – Milking Nanny Goats for Big Bucks

Antithrombin deficiency is a hereditary disease causing low levels or defects of antithrombin, a blood protein required for controlling clot formation. Patients are at risk of blood clots, organ damage, and death. They usually have to take oral anticoagulant drugs like warfarin for life.

During high-risk procedures like surgery or childbirth, oral anticoagulants must be discontinued to minimize the chance of bleeding complications. While patients are off oral anticoagulants, they are given preventive treatment with antithrombin derived from pooled human blood. With any human blood product there is a small risk of infection with diseases like hepatitis C. And human antithrombin supplies are not plentiful.

Clever researchers found an ingenious solution. Put a human antithrombin gene in goats, milk them, isolate the human antithrombin protein from the milk, and voila! An udderly safe and plentiful source. A Brit might call it bleatin’ brilliant. (more…)

Posted in: Pharmaceuticals, Science and Medicine

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Medical Marijuana: are we ready?

Cannabis has been used recreationally and medically for centuries. Despite long experience, relatively little is known about the risks and benefits of its use as a medication. A considerable portion of our ignorance can be attributed to government discouragement of cannabis research. Searching the NIH website brings up many studies of both cannabis abuse and cannabis as a therapeutic agent, but most of the general information available is about cannabis as a drug of abuse.

And there is no doubt about the abuse potential and withdrawal potential of marijuana except among hard core denialists. The data is clear: marijuana discontinuation is associated with a withdrawal syndrome in many users, with some experts likening it in symptoms and severity to nicotine withdrawal.

As with any pharmacologically active substance, there are no “side effects”, only effects which we desire and those we do not. Given that cannabis is clearly a powerful pharmacologic agent, that there is a great deal of anecdotal evidence supporting its use, and that there is scientific plausibility to these claims, its potential use as a therapeutic drug should be investigated seriously. (more…)

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