Everything you know may be wrong. Well, not really, but reading the research of John Ioannidis does make you wonder. His work, concentrated on research about research, is a popular topic here at SBM. And that’s because he’s focused on improving the way evidence is brought to bear on decision-making. His most famous papers get to the core of questioning how we know what we know (or what we assume) to be evidence. (more…)
Archive for Epidemiology
A good case of smallpox may rid the system of more scrofulous, tubercular, syphilitic and other poisons than could otherwise be eliminated in a lifetime. Therefore, smallpox is certainly to be preferred to vaccination. The one means elimination of chronic disease, the other the making of it.
Naturopaths do not believe in artificial immunization . . .
—Harry Riley Spitler, Basic Naturopathy: a textbook (American Naturopathic Association, Inc., 1948). Quoted here.
Here’s what a good case of smallpox will do for you:
If you’re lucky enough to beat the reaper (20-60%; 80% or higher in infants) or blindness (up to 30%), those blisters will leave you scarred for life. Oh, and the next time a good smallpox epidemic comes around, your children born since the last one will catch it and contribute their fair share to the death rate. But not you because you’ll be immune, so you’ll have the “preferred” experience of watching your children die well before you do.
The anti-vaccine movement is a frequent topic on the Science-Based Medicine blog. There are a number of reasons for this, not the least of which being that the anti-vaccine movement is one of the most dangerous forms of pseudoscience, a form of quackery that, unlike most forms of quackery, endangers those who do not partake of it by breaking down herd immunity and paving the way for the resurgence of previously vanquished diseases. However, anti-vaccine beliefs share many other aspects with other forms of quackery, including the reliance on testimonials rather than data. Even so, although the intelligentsia (and I do use the term loosely) of the anti-vaccine movement realizes and exploits the power of anecdotes and testimonials and how human beings tend to value such stories over dry scientific data, leaders of the anti-vaccine movement realize that science is overwhelmingly against them and that testimonials alone are not adequate to counter that science in the realm of public policy and relations.
That’s why, over the years, various anti-vaccine “scientists” (and I use that term very loosely as well) have produced poor quality, sometimes even fraudulent studies, which are then touted as evidence that vaccines cause autism or at least as evidence that there is actually still a scientific controversy when in fact from a scientific standpoint the vaccine-autism hypothesis is pining for the fjords. Examples abound, including the work of Mark and David Geier, whose studies led the to use chemical castration to treat autistic children; Andrew Wakefield, whose small case series almost certainly included fraudulent data; a truly incompetent “phone survey” commissioned by Generation Rescue designed to compare “vaxed versus unvaxed” children; and an even more incompetent “study” in which Generation Rescue used a cherry picked group of nations to try to argue that nations that require more vaccines have higher rates of infant mortality. These efforts continue. For example, last year Generation Rescue requested $809,721 from the Airborne settlement to set up a “vaxed versus unvaxed” study, despite the known difficulties with such a study and the low likelihood of finding anything without huge numbers of children.
Last week, they were at it again.
Could a vitamin with proven benefits in one group cause harm to another? That’s the growing concern with folic acid, the vitamin that dramatically reduces the risk of neural tube birth defects such a spina bifida. Studies designed to explore the possible benefits of folic acid for heart disease, stroke and cancer are giving out some worrying signs: At best, folic acid is ineffective, and at worst it may be increasing the risks of some cancers. So what does this say about routine supplementation for the typical healthy individual, and its overall risk and benefit?
Folate (vitamin B9) is an essential nutrient found green, leafy vegetables, broccoli, peas, corn, oranges, grains, cereals, and meats. Folate has important roles in the synthesis of DNA, and consequently cell division. Significant folate deficiency can lead to macrocytic anemia. Folic acid, a synthetic form of folate, is used in multivitamins supplements because it is better absorbed.
Folic acid’s benefits in pregnancy are well documented. Supplementation before conception, and in the first few weeks of pregnancy, significantly and substantially lower the risk of several different birth defects, including neural tube defects (NTDs). The neural tube is the embryonic precursor to the brain and spinal column. NTDs include very serious defects like spinal bifida and anencephaly, birth without part of the brain.
There are sources of information I inclined to accept with minimal questioning. I do not have time to examine everything in excruciating detail, and like most people, use intellectual short cuts to get through the day. If it comes from Clinical Infectious Diseases or the NEJM, I am inclined to accept the conclusions without a great deal of analysis, especially for non-infectious disease articles. Infectious disease publications I have to read more closely; its part of passing as an expert.
Outside of medicine, I am predisposed to accepting at face value many of the articles in Skeptic and Skeptical Inquirer. They are trusted sources. Some topics, like haunted house or Big Foot investigations, I barely skim. After all these years, I doubt there will be any new insights into the subject. Other topics, depending on my interest, I may read more carefully.
I often read longer articles many times. First a quick skim to see if it offers anything of interest. If it does, then I may read it carefully.
This months Skeptical Inquirer had an article called Seven Deadly Medical Hypotheses by Reynold Spector. Just seeing the title and knowing the magazine, I was primed to accept the content at face value. I enjoy a well reasoned, thoughtful rant. I relish a clever diatribe, even if I do not agree with the topic. So I gave it a quick skim. I was discomfited. My first gut check was ick. But I was uncertain why. So I read it slowly and carefully, and still ick. But why? (more…)
Following my recent critique here of the book Disconnect by Devra Davis, about the purported dangers of cell phones to health, David Gorski asked me to comment on a recently published “review article” on the same subject. The article is entitled “Risk of Brain Tumors from Wireless Phone Use” by Dubey et al  published in the J. Comput Assist Tomography. At the outset, the same question occurred to both of us: what is a “review article” about cell phones and brain tumors doing in a highly technical journal dedicated to CT scans and CT imaging? While we are both still guessing about the answer to this question, we agreed that the article itself is a hodge-podge of irrational analysis.
As you might surmise, Dubey and his Indian co-authors come to the conclusion that “that the current standard of exposure to microwave during mobile phone use is not safe for long-term exposure and needs to be revised.” But within the conclusion there is also the following: “There is no credible evidence from the Environmental Health and Safety Office (I presume in India) about the cause of cancer or brain tumors with the use of cell phones. It is illogical to believe that evidence of unusual brain tumors is only because of hundred’s of millions of people using cell phones worldwide.” What?! These are opposite and contradictory statements. The main body of the article includes a lot more instances of such inconsistency.
I must admit that I have a bit of a love-hate relationship with breast implants. On the one hand, as a breast cancer surgeon, I see them as a major benefit to my patients who are unfortunate enough to require mastectomy in order to control their disease. The armamentarium of techniques for reconstructing breasts after mastectomy generally falls into one of two categories, either various form of muscle flaps or breast implants. However, some women are, for various reasons, not eligible for various muscle flap reconstructions. That leaves either breast implants–or nothing. Certainly, some women are perfectly fine with no reconstruction after mastectomy, but many, if not most, women are not. For these women, it would be difficult to overstate how much of a boon to body image and self-esteem reconstruction can be, particularly given how much better at it plastic surgeons have become over the last couple of decades.
On the other hand, breast implants make my life as a breast cancer surgeon more difficult for a variety of reasons. First, they tend to make mammography more difficult by obscuring part of the breast, thus decreasing the sensitivity of mammography. Good mammography facilities can get around this to some extent by using various displacement techniques, but it takes some effort, and it doesn’t completely correct the problems that implants cause for mammographic screening. Moreover, when a woman who has had implants placed for cosmetic reasons comes to see me for a breast mass or an abnormal mammogram, the presence of the implants can complicate treatment decisions. If the abnormality or mass is close to the implant, we worry about rupturing it in the process, particularly if the implant is not below the pectoralis major muscle. Even when the implant is subpectoral, the muscle overlying it frequently ends up being so stretched out that the muscle in essence forms part of the capsule around the implant and ends up being a lot thinner than you might expect. Let me tell you, my anal sphincter tone is always much tighter when operating near an implant, particularly a silicone implant. True, I’m perfectly capable of removing an implant if it’s accidentally ruptured, but such an outcome is not desirable, particularly with silicone implants, where cleaning up the leaking silicone can be difficult.
It doesn’t help that silicone breast implants have been the subject of controversy since the late 1980s and early 1990s, when thousands of women with silicone implants reported a variety of ailments, including autoimmune disease and a variety of other systemic illnesses. These reports led to a rash of lawsuits and, ultimately, the banning of silicone breast implants for general use in 1992. After that, silicone breast implants were only permitted in women requiring breast reconstruction or women enrolled in clinical trials studying breast implants. This ban was partially lifted in 2006, as evidence accumulated that the claims of autoimmune diseases and increased cancer risk due to silicone breast implants were not supported by clinical and scientific evidence and two products made by Allergan Corp. (formerly Inamed Corp.) and Mentor Corp. Not surprisingly, given that the furor over silicone breast implants as a cause of autoimmune and other systemic diseases is based on about as much solid scientific evidence as the antivaccine furor over vaccines as a cause of the “autism epidemic,” there was widespread criticism of this decision. Even now, it is not difficult to find articles about breast implants with titles like Breast Implants: America’s Silent Epidemic and websites like the Humantics Foundation and Toxic Breast Implants . I do note, however, that the number of such sites and articles does appear to be declining and, at least to my impression, seems to have decreased markedly over the last 10 years or so.
Having reviewed the literature and found evidence for a link between silicone breast implants and the systemic diseases attributed to them to be incredibly weak at best, I had little problem with the FDA’s decision. Actually, the only thing I had a problem with at the time, my opinions of how breast implants interfere with breast cancer detection and treatment notwithstanding, is that the FDA was probably being more cautious than the evidence warranted after 14 years.
Was I wrong?
A recent Cochrane review of the use of cholesterol-lowering statin drugs in primary prevention has sparked some controversy. The controversy is not so much over what the data says, but in what conclusions to draw from the data.
Statin drugs have been surrounded by controversy for a number of reasons. On the one hand they demonstrably lower cholesterol, and the evidence has shown that they also reduce the incidence of heart attacks and strokes. The data on whether or not they reduce mortality has been less clear, although this latest data actually supports that claim. However, statins have also been blockbuster drugs for pharmaceutical companies and this has spawned concerns (some might say paranoia) that drug companies are pushing billions of dollars worth of marginally effective drugs onto the public.
So are statins a savior or a scam? Life does not always provide nice clean answers to such simple dichotomies. The evidence clearly shows that statins work and are safe. However, pharmaceutical companies do like to present their data in the best light possible, and they need to be watched closely for this. The recent review does call them on some practices that might tend to exaggerate the utility of statins. Finally, the real question comes down to – where should we draw the line in terms of cost-benefit of a preventive measure like statins.
Let’s look as this recent review of the data to see what it actually shows.
It seems that for every established science there is an ideological group who is motivated to deny it. Denialism is a thriving pseudoscience and affects any issue with the slightest political or social implications. Sometimes, even easily verifiable facts can be denied, as people seem willing to make up their own facts as needed.
Denialists have an easy job – to spread doubt and confusion. It is far easier to muddy the waters with subtle distortions and logical fallacies than it is to set the record straight. Even when every bit of misinformation is countered, the general public is often left with the sense that the topic is controversial or uncertain. If denial is in line with a group’s ideology, then even the suggestion of doubt may be enough to reject solid science.
We see this when it comes to the effectiveness of vaccines, the evolution of life on earth, and anthropogenic global warming. A recent Pew poll shows that the campaign of global warming denial has been fairly successful – while the science becomes more solid around the consensus that the earth is warming and humans are contributing to this, the public is becoming less convinced.
Disconnect: The Truth About Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family by Devra Davis, PhD is touted as a book about the issue of cell phones and health. It is instead a tract that conspiracy theorists will love that sheds no objective light on the often confusing scientific data in this area. The tag line on the jacket sets the tone: The TRUTH about cell phone RADIATION. What the INDUSTRY has done to hide it, and how to PROTECT your FAMILY. In the area of EMF and health, there are a certain number of studies that appear to find biological “effects”. This is perfect fodder for alarmists like Davis, who ignore the fact that virtually none of these “effects” have been reproduced in follow up studies. If you were expecting an objective review of the often confusing scientific data in this area, you should avoid this book.
Disconnect focuses almost exclusively on studies that support its alarmist conclusions while either ignoring or falsifying information about studies showing no harm. The quality of scientific studies varies greatly. Disconnect is highly selective and totally biased in discussing only studies that support its point of view, it rejects contrary studies accepted by the majority of mainstream scientists as the product of some vast conspiracy, and it completely misstates the findings of key studies that find no harm from cell phones. She interviewed only a relatively small group of dissident scientists who are outside of the mainstream. The book is completely lacking in objectivity.
Major Factual Misstatements
There are so many things wrong in Disconnect that it is difficult to know where to begin. We will start by reviewing a few of the most blatant examples of how it misrepresents key findings of some of the most important cell phone studies.