Red meat consumption has been linked to diabetes, cardiovascular disease, and several types of cancer (breast, colorectal, stomach, bladder, prostate, and lymphoma). There are plausible mechanisms: meat is a source of carcinogens, iron that may increase oxidative damage, and saturated fat. But correlation and plausibility are not enough to establish causation. Is red meat really dangerous? If so, how great is the risk? A couple of recent studies have tried to shed light on these questions, but they have raised more questions than they have answered.
A Systematic Review and Meta-Analysis
A new study in Circulation, “Red and Processed Meat Consumption and Risk of Incident Coronary Heart Disease, Stroke, and Diabetes Mellitus. A Systematic Review and Meta-Analysis,” by Micha, Wallace and Mozaffarian, is a systematic review of the literature. It analyzed 17 prospective cohort studies and 3 case-control studies, with a total of 1.2 million subjects. As far as I can judge, it appears to be a well-done systematic review with excellent methodology and multiple precautions. They even looked for things like publication bias (which they did not find).
They found that the consumption of processed meats, but not red meats, is associated with a higher incidence of coronary heart disease and diabetes. (Processed meats include bacon, sausage, ham, hot dogs, salami, luncheon meat and other cured meats.) The increased risk per 50 gram serving of processed meats per day was 42% for heart disease and 19% for diabetes. Unprocessed red meats were not associated with CHD and were associated with a nonsignificant trend towards higher risk of diabetes. They found no association with stroke, but this was based only on 3 studies.
In the world of the anti-vaccine underground, there is one time of the year that looms large. Over the last few years, this time has generally come right around the end of May, usually coinciding with the Memorial Day weekend and the unofficial beginning of the summer vacation season here in the U.S. I’m referring, of course, to Autism One, which blights one of my favorite cities in the world, Chicago, every year about this time. True, of late Autism One has been metastasizing, most recently to blight the city of Toronto and the very grounds of the University of Toronto itself. As you may recall, last fall, when Autism One descended upon Toronto, I described it as “a conference of believers in two things: (1) that vaccines cause autism and (2) that ‘biomedical’ and CAM/IM therapies can treat and even reverse autism,” and it’s true, but Autism One is more than that. It’s a combination of a networking meeting for the anti-vaccine set, a revival meeting for the cult of anti-vaccinationism and autism “biomedical” therapy, and a trade show for “biomed” treatments for autism, all dressed up to appear to be a legitimate scientific conference.
Of all the fake scientific conferences out there, Autism One in Chicago, which begins today, far eclipses all the others, including even Barbara Loe Fisher’s National Vaccine Information Center (NVIC) conference. Closely aligned with the anti-vaccine propaganda group Generation Rescue and its outlet in the blogosphere Age of Autism (both of which, not surprisingly, have been promoting the conference incessantly), Autism One is the granddaddy of fake academic autism conferences, where anyone who’s anyone in the anti-vaccine “autism biomed” underground goes to see and be seen. It even has a keynote address by anti-vaccine celebrity spokesmodel Jenny McCarthy herself this year, just like the previous two years. This year, however, Autism One has expanded from three or four days to a full week, and it has taken on a note of political activism that was generally lacking in previous conferences. In previous years, Autism One pretty much stayed localized to a hotel near O’Hare, far from the center of the city. This time around it’s still at a hotel near O’Hare, but its organizers plan an anti-vaccine protest rally right smack dab in the middle of Grant Park on Wednesday afternoon. All of this leads me to conclud that this year Autism One’s organizers appear to be cementing the relationship between the autism “biomed” movement, the anti-vaccine movement, and the “health freedom” movement.
I’ve blogged a lot about anti-vaccine hero Andrew Wakefield over the years. The story has become long and convoluted, and to tell it takes a lot of verbiage, even by my standards (or those of Kimball Atwood). However, I’ve found a good resource that tells the tale of Andrew Wakefield and his misdeeds in a highly accessible form:
The question at the very end of the story is about as appropriate as it gets. Unfortunately, the answer to the question is: Yes.
The Institute of Medicine report is a frequent ‘rebuttal’ to science based/real medicine. The argument is usually phrased something to the effect that since medicine can be dangerous, SCAM’s are legitimate. Of course, one does not follow the other. It is the equivalent of saying since you are old, bald and pudgy, I am young, have a full head of hair, and are thin. If every doctor and hospital were to vanish tomorrow like an episode of the Outer Limits, SCAM’s would be just a ineffective.
Despite the flawed logic of the comparison, I have always had an affinity for the estimates that 44,000 to 98,000 were (note the deliberate use of the past tense) killed each year in hospitals. There may be methodological flaws in the estimate but the ballpark figure is probably correct.
For SBM readers in the Toronto area, I’ll be speaking on Friday, May 28, at the Centre for Inquiry on how science advocates can help support better health decisions:
Despite the dramatic improvements in the extent and quality of our lives, largely owing to modern medicine, our current health care system has fostered a backlash, manifested in part by the emergence of non-science-based “alternative” health care practices. This trend has driven a need for dialogue on how best we should balance evidence-based decisions against demands for consumer choice – regardless of the science. In this presentation, Scott Gavura will discuss how health care decision-making differs from other goods and services, and how this impacts on the choices we make, both as individuals, and in aggregate. Through an interactive discussion, he will facilitate a dialogue on the opportunities for science advocates to effect positive change in health at the patient- and population-level.
Science advocates have the evidence to support their positions. How do we translate this evidence to support effective decision making? On May 28, join the conversation.
Get the event details, and you can RSVP on Facebook. The talk is great value-for-money: $5, $4 for students, and free for CFI members.
Naturopathy is an unusual chimera. It is basically a collection of old fashioned medical superstitions presented under a veneer of highly speculative, quasi-scientific assertions. But given its popularity, it is important, from time to time, to evaluate specific claims made by this particular non-science-based belief system.
A reader informed me that he was advised to seek the advice of a naturopath for treatment of his seasonal allergies. Since naturopaths claim to be “doctors plus”, I was curious what they would recommend. Would it be standard allergy treatment with antihistimines and other proven medications along with some sort of vitalistic mumbo-jumbo? It turns out I was half-right.
About a week and a half ago, the ever-ascerbic Mark Crislip applied his dry and devastating wit to a particularly silly bit of anti-vaccine propaganda from an anti-vaccine website, Medical Voices Vaccine Information Center (MVVIC). Written by a naturopath named David Mihalovic, the anti-vaccine propaganda in question was entitled 9 Questions That Stump Every Pro-Vaccine Advocate and Their Claims. Mihalovic’s article is an incredibly — shall we say? — target-rich environment full of logical fallacies (including straw men built to Burning Man dimensions at which Mihalovic aimed his flamethrower of burning ignorance and let loose with napalm-grade flaming nonsense), misinformation, and cherry picking. Dr. Crislip entitled his rejoinder, appropriately enough, Nine Questions, Nine Answers, and his methodical, oh-so-sarcastically complete deconstruction of Mihalovic’s deceptive and disingenuous “nine questions” showed that these questions stump no one who actually knows what he is talking about when it comes to vaccines. More than that, these “nine questions” also reveal an ignorance of vaccines so deep that a bathysphere probably couldn’t withstand the pressure at that depth. Truly, after reading Dr. Crislip’s post, I had to bow to the master. I may be capable of some fairly awesome insolence at times, but I’m hard-pressed to keep up with Dr. Crislip when he’s firing on all cylinders.
Being the ever-benevolent editor that I am and, as such, very proud of Mark’s effort, I decided that common courtesy would suggest that it would be a good idea to send a friendly note to the people behind Medical Voices, you know, just to let them know that their article had been greatly appreciated for its entertainment value. Well, maybe the e-mail wasn’t so friendly. I do recall using the words “nonsense,” “pseudoscience,” “misinformation,” and “despicable” somewhere in the mix. Antivaccine pseudoscience tends to bring that out in me, and it wasn’t a blog post, at least not on SBM. Be that as it may, over a week went by with no response, and I thought that we were being ignored. Oh, well, I thought, no big deal and nothing unexpected. Then, Monday morning, I found this e-mail in my in box from someone named Nick Haas:
Hello Dr. Gorski,
Would you like to debate on vaccines live and publicly over the Internet? You just need a computer and a headset. We could have two medical doctors on each side. We’ll figure out a moderator together.
A “live” debate. What is it with “live debates”? It seems that cranks always want to challenge those who criticize their misinformation and pseudoscience to “live debates.”
This is a science and medicine story we have been following for a while – out of personal and scientific interest, and the need to correct confused or misleading new reporting on the topic. Are cell phones linked to an increased risk of brain cancer or other tumors? New data is reassuring.
David Gorski and I have both written on this topic. To give a quick summary, there is no convincing data to link cell phone use and brain cancer. Epidemiological studies have not found an increase in the incidence of brain cancer following the widespread adoption of cell phones in the mid 1990s – as one would expect if there were a causal relationship. Further, large scale studies have not found any consistent correlation between cell phone use and brain cancer.
It is clear from the literature that there is no measurable increased risk from short term cell phone use – less than 10 years. There is no evidence to conclude that there is a risk from long term use (> 10 years) but we do not yet have sufficient long-term data to rule out a small risk. Further, the data is somewhat ambiguous when it comes to children – still no convincing evidence of a link, but we cannot confidently rule out a link.
We know that drinking alcohol during pregnancy can cause birth defects; the government-mandated warnings on alcoholic beverage labels constantly remind us of that fact. But toxicologists remind us that the poison is in the dose: what is the dose of alcohol that causes birth defects? Heavy drinking can cause fetal alcohol syndrome, but there is no evidence that light to moderate drinking can cause it. Alcohol has been implicated in a number of other adverse effects on pregnancy and on the fetus. We simply don’t know if there is a threshold dose below which alcohol intake is safe, so the default position of most medical authorities has been to advise total abstinence during pregnancy. This is not a truly evidence-based recommendation, but rather an invocation of the precautionary principle. Those advising complete abstinence have been accused of paternalism and bias by wine-lovers and other critics, for instance here and here.
The literature on alcohol and pregnancy is extensive and confusing. It addresses many different endpoints, looking at effects on children and on the pregnancy itself. The studies are inconsistent in how they define “moderate” or “light” drinking, and they rely on self-reports that may not be accurate.
It would be impossible to read and accurately summarize such a large body of literature (over 21,000 hits on PubMed!), but here are a few examples that illustrate the scope, diversity, and conflicting results of these studies: (more…)
The road from an idea to a useful drug is a long one, and in cancer it is often particularly long. One reason is that to be able to tell whether a given treatment is effective against cancer often takes several years at a minimum, in order to determine if patients receiving the new treatment are surviving their disease longer than those who are not. Surrogate endpoints are usually not enough. Tumor shrinkage in response to a drug often does not correlate with prolongation of survival, although the converse (i.e., lack of tumor shrinkage in response to a new drug) does strongly correlate with failure of a treatment to prolong survival. In other words, effects observed on surrogate endpoints are not enough to judge whether a cancer therapy is working or not.
Three years ago, predating the existence of this blog by nearly a year, I became aware of a story that involved many of the issues in bringing a compound from the laboratory to the clinic. The case was unusual in that is is very rare to see the scientific process by which new drugs progress through the stages of cancer research, from concept to testing in cell culture to testing in animals to testing in humans challenged so strongly by patients themselves. The reason that this normally doesn’t occur is that new cancer treatments are almost always the product of either university-conducted research, pharmaceutical company-conducted research, or partnerships between the two. This case was markedly different in that it involved a chemical that was not only easy to synthesize, but cheap and long out of patent. Even more intriguing, it targeted a metabolic abnormality found in many cancer cells, an abnormality first described nearly 80 years before by Otto Warburg in 1928. This latter aspect of the drug gave it every appearance of a “rediscovery” of old wisdom that big pharma had ignored for 80 years, and that only added to its mystique.
The chemical was dichloroacetate (DCA), and three years ago it created a world-wide sensation. Last week, it created a sensation again, as breathless news reports once again overhyped its promise. Since I’ve been following the story since early 2007, I appear to be in as good a position as anyone to tell the story thus far and put the new findings into context. To begin that process, let’s head back to January 2007.