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Posts Tagged meta-analysis

The rise and inevitable fall of Vitamin D

Is Vitamin D a panacea? The evidence says otherwise.

Is vitamin D a panacea? The evidence says otherwise.

It’s been difficult to avoid the buzz about vitamin D over the past few years. While it has a  long history of use in the medical treatment of osteoporosis, a large number of observational studies have linked low vitamin D levels to a range of illnesses. The hypothesis that there is widespread deficiency in the population has led to interest in measuring vitamin D blood levels. Demand for testing has jumped as many physicians have incorporated testing into routine care. This is not just due to alternative medicine purveyors that promote vitamin D as a panacea. Much of this demand and interest has been driven by health professionals like physicians and pharmacists who have looked at what is often weak, preliminary and sometimes inconclusive data, and concluded that the benefits of vitamin D outweigh the risks. After all, it’s a vitamin, right? How much harm can vitamin D cause? (more…)

Posted in: Herbs & Supplements, Nutrition

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Influenza Eye Roll

Look!  A metaphor!

Look! A metaphor!

I don’t know the best metaphor. What comes around goes around. The more things change, the more they say the same. Sisyphus. Whack-A-Mole.

So what to do when the same old same old rears its head yet again? There are 2,545 posts on this blog, and I suppose I could just point to prior posts. But a blog entry that consists of links to prior posts would make the managing editor irritable. And we don’t want him irritable. Although those links are at the end of the post.

And WordPress is not a good format for reference material. I have trouble finding my own articles even when I know they exist and search for them using what I think are relevant terms.

It being the start of the flu season the same ole same ole nonsense is back about flu vaccines and influenza treatment. Influenza seasons vary, the nonsense does not. On the assumption that most of the readers of the post have no prior knowledge of what I have written on the topic, I thought I would tackle influenza yet again. (more…)

Posted in: Clinical Trials, Critical Thinking, Science and Medicine

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“Electromagnetic hypersensitivity” and “wifi allergies”: Bogus diagnoses with tragic real world consequences

Is there such a thing as an "allergy to wifi"? Lots of people claim there is; science, not so much.

Is there such a thing as an “allergy to wifi”? Lots of people claim there is; science, not so much.

I debated about writing about this topic, given that I just wrote about it last week on my not-so-super-secret other blog. However, as I thought about it during the weekend, I realized that the tragic story that so saddened and disturbed me to prod me to discuss so-called “electromagnetic hypersensitivity” or “electro-hypersensitivity” (EHS) was so horrific that a more detailed, SBM-level discussion was indicated, particularly in light of a similar case electromagnetic hypersensitivity that didn’t end so tragically discussed by Harriet Hall in September. I’m referring, of course, to the case of Jenny Fry, a British teen who hanged herself in June and whose mother has been claiming that her “allergy to wifi” was what drove her to suicide. So, while there will be some overlap with my previous discussion, I will try to step back and take a broader view of the evidence regarding the fake diagnosis of EHS, interspersed with examples (hopefully) illustrating my point. Think of this as the post I wished I had written the first time around but, due to time constraints, couldn’t.

Bogus science and lawsuits over EHS

By way of background, it’s worth briefly revisiting the case that Harriet discussed. Indeed, if you Google “lawsuit” and “electromagnetic hypersensitivity” and “wifi” the first two pages of results consist mostly of articles discussing it. That’s probably because this is just the latest lawsuit that made the news. It happened in Massachusetts, where the parents of a 12-year-old boy (designated “G” in court records) who was attending Fay School in Massachusetts alleged that the school violated his rights under the Americans with Disabilities Act by failing to make accommodations to protect G from electromagnetic radiation from the school’s wifi routers. From the complaint’s summary statement:
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Posted in: Basic Science, Neuroscience/Mental Health, Public Health

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Low Energy Sweeteners and Weight Control

artificial-sweetenersA new systematic review published in the International Journal of Obesity looks at the totality of evidence investigating whether consuming low energy sweeteners (LES), such as aspartame, sucralose, or stevia, is a net benefit or detriment for weight control. In addition to providing some clarity on the answer, the review also provides some insight into how different kinds of evidence address such questions.

LES vs sugar or water

The question may at first seem obvious – if you consume a beverage sweetened with an LES instead of sugar you will be avoiding up to several hundred calories. Those calories add up quickly. Twelve ounces of cola with sugar has 138 calories, for example. These are foods that people generally consume on a daily basis, and so avoiding these unnecessary calories should reduce total energy intake and help reduce or maintain weight.

The human body, however, is a complex system, as is human psychology, and so we have to consider the law of unintended consequences. It is possible, for example, that when people drink a diet beverage they feel they have earned the right to consume more calories elsewhere. This phenomenon is called compensation, and there is evidence for this effect.

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Posted in: Nutrition

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Screening for disease in people without symptoms: The reality

One of the most contentious questions that come up in science-based medicine that we discuss on this blog is the issue of screening asymptomatic individuals for disease. The most common conditions screened for that we, at least, have discussed on this blog are cancers (e.g., mammography for breast cancer, prostate-specific antigen screening for prostate cancer, ultrasound screening for thyroid cancer), but screening goes beyond just cancer. In cancer, screening is a particularly-contentious issue. For example, by simply questioning whether mammography saves as many lives lost to breast cancer as advocates claim, one can find oneself coming under fire from some very powerful advocates of screening who view any questioning of mammography as an attempt to deny “life-saving” screening to women. That’s why I was very interested when I saw a blog post on The Gupta Guide that pointed me to a new systematic review by John Ioannidis and colleagues examining the value of screening as a general phenomenon, entitled “Does screening for disease save lives in asymptomatic adults? Systematic review of meta-analyses and randomized trials.”

Before I get into the study, let’s first review some of the key concepts behind screening asymptomatic individuals for disease. (If you’re familiar with these concepts, you can skip to the next section.) The act of screening for disease is based on a concept that makes intuitive sense to most people, including physicians, but might not be correct for many diseases. That concept is that early intervention is more likely to successfully prevent complications and death than later intervention. This concept is particularly strong in cancer, for obvious reasons. Compare, for example, a stage I breast cancer (less than 2 cm in diameter, no involvement of the lymph nodes under the arm, known as axillary lymph nodes) with a stage III cancer (e.g., a tumor measuring greater than 5 cm and/or having lots of axillary lymph nodes involved). Five year survival is much higher for treated stage I than for treated stage III, and, depending on the molecular characteristics, the stage I cancer might not even require chemotherapy and can be treated with breast conserving surgery (“lumpectomy” or partial mastectomy) far more frequently than the stage III cancer. So it seems intuitively true that it would be better to catch a breast cancer when it’s stage I rather than when it’s stage III.
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Posted in: Cancer, Clinical Trials, Epidemiology, Public Health

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Systematic Review claims acupuncture as effective as antidepressants: Part 1: Checking the past literature

acupuncture

A recent systematic review in PLOS One raised the question whether acupuncture and other alternative therapies are as effective as antidepressants and psychotherapy for depression. The authors concluded

 differences were not seen with psychotherapy compared to antidepressants, alternative therapies [and notably acupuncture] or active intervention controls

or put it differently,

antidepressants alone and psychotherapy alone are not significantly different from alternative therapies or active controls.

There are clear messages here. To consumers: Why take antidepressants with their long delay and uncertainty in showing any benefits–but immediate side effects and potential risks–when a few sessions of acupuncture work just as well? To promoters of acupuncture and alternative therapies: you can now cite an authoritative review in the peer-reviewed PLOS One as scientific evidence that your treatments is as effective as scary antidepressants and time-consuming psychotherapy when you make appeals to consumers and to third-party payers.

The systematic review had five co-authors, of whom three have been involved in previous meta-analyses of the efficacy of antidepressants. However, fourth author Irving Kirsch will undoubtedly be the author most recognizable to consumers and policymakers, largely because his relentless media campaign claiming antidepressants are essentially worthless, no better than placebo. For instance, in an interview with CBS 60 Minutes Irving Kirsch: The difference between the effect of a placebo and the effect of an antidepressant is minimal for most people.

Irving Kirsch: The difference between the effect of a placebo and the effect of an antidepressant is minimal for most people.
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Posted in: Acupuncture, Neuroscience/Mental Health, Science and the Media

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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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Fun with homeopaths and meta-analyses of homeopathy trials

ResearchBlogging.orgHomeopathy amuses me.

Well, actually it both amuses me and appalls me. The amusement comes from just how utterly ridiculous the concepts behind homeopathy are. Think about it. It is nothing but pure magical thinking. Indeed, at the very core of homeopathy is a concept that can only be considered to be magic. In homeopathy, the main principles are that “like heals like” and that dilution increases potency. Thus, in homeopathy, to cure an illness, you pick something that causes symptoms similar to those of that illness and then dilute it from 20C to 30C, where each “C” represents a 1:100 dilution. Given that such levels of dilution exceed Avagaddro’s number by many orders of magnitude, even if any sort of active medicine was used, there is no active ingredient left after a series of homeopathic dilutions. Indeed, this was known as far back as the mid-1800’s. Of course, this doesn’t stop homeopaths, who argue that water somehow retains the “essence” of whatever homeopathic remedy it has been in contact with, and that’s how homeopathy “works.” Add to that the mystical need to “succuss” (vigorously shake) the homeopathic remedy at each dilution (I’ve been told by homeopaths, with all seriousness, that if each dilution isn’t properly succussed then the homeopathic remedy will not attain its potency), and it’s magic all the way down, just as creationism has been described as “turtles all the way down.” Even more amusing are the contortions of science and logic that are used by otherwise intelligent people to make arguments for homeopathy. For example, just read some of Lionel Milgrom‘s inappropriate invocations of quantum theory at the macroscopic level for some of the most amazing woo you’ve ever seen, or Rustum Roy‘s claims for the “memory of water.” Indeed, if you want to find out just how scientifically bankrupt everything about homepathy is, my co-blogger Dr. Kimball Atwood started his tenure on Science-Based Medicine with a five part series on homeopathy.

At the same time, homeopathy appalls me. There are many reasons for this, not the least of which is how anyone claiming to have a rational or scientific viewpoint can fall so far as to twist science brutally to justify magic. Worse, homepaths and physicians sucked into belief into the sorcery that his homeopathy are driven by their belief to carry out unethical clinical trials in Third World countries, even on children. Meanwhile, time, resources, and precious cash are wasted chasing after pixie dust by our own government through the National Center for Complementary and Alternative Medicine (NCCAM). So while I laugh at the antics of homeopaths going on and on about the “memory of water” or quantum gyroscopic models” in order to justify homeopathy as anything more than an elaborate placebo, I’m crying a little inside as I watch.

The Lancet, meta-analysis, and homeopathy

If there’s one thing that homepaths hate–I mean really, really, really hate–it’s a meta-analysis of high quality homeopathy trials published by Professor Matthias Egger in the Department of Social and Preventative Medicine at the University of Berne in Switzerland, entitled Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy.
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Posted in: Clinical Trials, Homeopathy

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