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Are the benefits of breastfeeding oversold?

As a mother, I am a passionate advocate of breastfeeding and I breastfed my four children. As a clinician, though, I need to be mindful not to counsel patients based on my personal preferences, but rather based on the scientific evidence. While breastfeeding has indisputable advantages, the medical advantages are quite small. Many current efforts to promote breastfeeding, while well meaning, overstate the benefits of breastfeeding and distorts the risks of not breastfeeding, particularly in regard to longterm benefits.

As Joan Wolf explains in an article entitled Is Breast Really Best? Risk and Total Motherhood in the National Breastfeeding Awareness Campaign:

… Medical journals are replete with contradictory conclusions about the impact of breast-feeding: for every study linking it to better health, another finds it to be irrelevant, weakly significant, or inextricably tied to other unmeasured or unmeasurable factors. While many of these investigations describe a correlation between breast-feeding and more desirable outcomes, the notion that breast-feeding itself contributes to better health is far less certain, and this is a crucial distinction that breast-feeding proponents have consistently elided. If current research is a weak justification for public health recommendations, it is all the more so for a risk-based message that generates and then profits from the anxieties of soon-to-be and new mothers…

Wolf describes the problems with many studies of breastfeeding, particularly those that focus on long term outcomes:

In breast-feeding studies, potential confounding makes it difficult to isolate the protective powers of breast milk itself or to rule out the possibility that something associated with breast-feeding is responsible for the benefits attributed to breast milk. As the number of years between breastfeeding and the measured health outcome grows, so too does the list of possibly influential factors, which means that the challenge is magnifiedwhen trying to evaluate long-term benefits of breastfeeding… Breast-feeding, in other words, cannot be distinguished from the decision to breast-feed, which, irrespective of socioeconomic status or education,could represent an orientation toward parenting that is itself likely to have a positive impact on children’s health. In instances such as this, in which the exposure (breast-feeding) and confounder (behavior) are likely to be very highly correlated, confounding is especially difficult to detect. When behavior associated with breast-feeding has the potential to explain much of the statistical advantage attributed to breast milk, the scientific claim that breast-feeding confers health benefits … needs to be reexamined.

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Posted in: Nutrition, Obstetrics & gynecology

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Communicating with the Locked-In

The primary reason that I and others favor science-based medicine, as opposed to the alternatives, is that science works. As Carl Sagan said, “Science delivers the good.” Science has other virtues – it is transparent and self-corrective also.

Recently two unrelated news items have provided an opportunity to compare a scientific vs a pseudoscientific approach to the same problem – that of communicating to patients who are locked-in.

Locked-in describes those who suffer from an injury or neurological disease that mostly paralyzes them, so that they cannot move or communicate. One scenario that leads to a locked-in state is a brainstem stroke, where patients are paralyzed below the eyes – they can only blink and move their eyes, but nothing else. Widespread trauma can lead to a similar situation. ALS, which leads to progressive loss of motor neurons, can also result in total or near total paralysis.

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Posted in: Neuroscience/Mental Health

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The One True Cause of All Disease

Note: This is a slightly modified version of an article that was published in the magazine Skeptical Inquirer, Volume 34, No. 1, January/Februrary 2010. It is reprinted here with the kind permission of the Committee for Skeptical Inquiry.

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Chiropractors, homeopaths, naturopaths, acupuncturists, and other alternative medicine practitioners constantly criticize mainstream medicine for “only treating the symptoms,” while alternative medicine allegedly treats “the underlying causes” of disease.

Nope. Not true. Exactly backwards. Think about it. When you go to a doctor with a fever, does he just treat the symptom? No, he tries to figure out what’s causing the fever and if it’s pneumonia, he identifies which microbe is responsible and gives you the right drugs to treat that particular infection. If you have abdominal pain, does the doctor just give you narcotics to treat the symptom of pain? No, he tries to figure out what’s causing the pain and if he determines you have acute appendicitis he operates to remove your appendix.

I guess what they’re trying to say is that something must have been wrong in the first place to allow the disease to develop. But they don’t have any better insight into what that something might be than scientific medicine does. All they have is wild, imaginative guesses. And they all disagree with one another. The chiropractor says if your spine is in proper alignment you can’t get sick. Acupuncturists talk about the proper flow of qi through the meridians. Energy medicine practitioners talk about disturbances in energy fields. Nutrition faddists claim that people who eat right won’t get sick. None of them can produce any evidence to support those claims. No alternative medicine has been scientifically shown to prevent disease or to cure it. If it had, it would have been incorporated into conventional medicine and would no longer be “alternative.”

Are these practitioners treating the underlying cause, or are they simply applying their one chosen tool to treat everything? Chiropractors treat every patient with chiropractic adjustments. What if a doctor used one treatment for everything? You have pneumonia? Here’s some penicillin. You have a broken leg? Here’s some penicillin. You have diabetes? Here’s some penicillin. Acupuncturists only know to stick needles in people. Homeopaths only know to give out ridiculously high dilutions that amount to nothing but water. Therapeutic touch practitioners only know to smooth out the wrinkles in imaginary energy fields. They are not trying to determine any underlying cause: they are just using one treatment indiscriminately. (more…)

Posted in: General

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Acupuncture, the P-Value Fallacy, and Honesty

Credibility alert: the following post contains assertions and speculations by yours truly that are subject to, er, different interpretations by those who actually know what the hell they’re talking about when it comes to statistics. With hat in hand, I thank reader BKsea for calling attention to some of them. I have changed some of the wording—competently, I hope—so as not to poison the minds of less wary readers, but my original faux pas are immortalized in BKsea’s comment.

Lies, Damned Lies, and…

A few days ago my colleague, Dr. Harriet Hall, posted an article about acupuncture treatment for chronic prostatitis/chronic pelvic pain syndrome. She discussed a study that had been performed in Malaysia and reported in the American Journal of Medicine. According to the investigators,

After 10 weeks of treatment, acupuncture proved almost twice as likely as sham treatment to improve CP/CPPS symptoms. Participants receiving acupuncture were 2.4-fold more likely to experience long-term benefit than were participants receiving sham acupuncture.

The primary endpoint was to be “a 6-point decrease in NIH-CSPI total score from baseline to week 10.” At week 10, 32 of 44 subjects (73%) in the acupuncture group had experienced such a decrease, compared to 21 of 45 subjects (47%) in the sham acupuncture group. Although the authors didn’t report these statistics per se, a simple “two-proportion Z-test” (Minitab) yields the following:

Sample X   N   Sample p

1            32  44   0.727273

2           21  45   0.466667

Difference = p (1) – p (2)

Estimate for difference: 0.260606

95% CI for difference: (0.0642303, 0.456982)

Test for difference = 0 (vs not = 0): Z = 2.60 P-Value = 0.009

Fisher’s exact test: P-Value = 0.017

Wow! A P-value of 0.009! That’s some serious statistical significance. Even Fisher’s more conservative “exact test” is substantially less than the 0.05 that we’ve come to associate with “rejecting the null hypothesis,” which in this case is that there was no difference in the proportion of subjects who had experienced a 6-point decrease in NIH-CSPI scores at 10 weeks. Surely there is a big difference between getting “real” acupuncture and getting sham acupuncture if you’ve got chronic prostatitis/chronic pelvic pain syndrome, and this study proves it!

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Posted in: Acupuncture, Clinical Trials, Science and Medicine

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Another wrinkle to the USPSTF mammogram guidelines kerfuffle: What about African-American women?

A while back I wrote about rethinking how we screen for breast cancer using mammography. Basically, the USPSTF, an independent panel of physicians and health experts that makes nonbinding recommendations for the government on various health issues, reevaluated the evidence for routine screening mammography and concluded that for women at normal risk for breast cancer, mammography before age 50 should not be recommended routinely and should be ordered on an individualized basis, and that routine formalized breast self-examination (BSE) should also not be routinely recommended. In addition, for women over 50, it was recommended that they undergo mammography every other year, rather than every year. These recommendations were based on a review of the literature, including newer studies.

To say that these new recommendations caused a firestorm in the breast cancer world is an understatement. The USPSTF was accused of misogyny; opponents of health care reform leapt on them as evidence that President Obama really is preparing “death panels”; and HHS secretary Kathleen Sebelius couldn’t run away from the guidelines fast enough. Meanwhile, a society I belong to (the American Society of Breast Surgeons) issued a press release accusing the USPSTF of sending us back to the “pre-mammography” days when, presumably women only found breast cancer after it had grown to huge size (just like Europe and Canada, I guess, given that the recommendations for screening there closely mirrors those recommended by the USPSTF). Meanwhile, in the most blatant example of protecting its turf I’ve seen in a very long time, the American College of Radiology went full mental jacket with a press release that was as biased as it was insulting. Meanwhile some physicians even likened the recommendations to going back to being like Africa, Southeast Asia and China as far as breast screening goes in that he actually speculated that he’d now become very busy treating advanced, neglected breast cancers. Unfortunately, as Val pointed out, the communication of the USPSTF guidelines to the public was almost a perfect case study in how not to do it. Even though the science was in general sound and the USPSTF recommendations were in essence close to identical to what other industrialized nations do, they were communicated in just such a way as to produce maximum misunderstanding and misuse for political purposes.

Despite all the hysterical and in some cases disingenuous attacks on the new guidelines, there is one criticism that actually resonates with me because I work at a cancer center in a very urban environment with a large population of African-American women. Last week I heard on NPR this story:
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Posted in: Cancer, Clinical Trials, Public Health

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Cell phones and cancer again, or: Oh, no! My cell phone’s going to give me cancer! (revisited)

ResearchBlogging.orgIt’s been about a year and a half since I’ve written about this topic; so I thought I’d better update the disclaimer that I wrote at the beginning:

Before I start into the meat of this post, I feel the need to emphasize, as strongly as I can, four things:

  1. I do not receive any funding from the telecommunications industry in general, or wireless phone companies in particular. None at all. In other words, I’m not in the pocket of “big mobile” any more than I am in the pocket of big pharma.
  2. I don’t own any stock in telecommunications companies, other than as parts of mutual funds in which my retirement funds are invested that purchase shares in many, many different companies, some of which may or may not be telecommunications companies.
  3. None of my friends or family work for cell phone companies.
  4. I don’t have a dog in this hunt. I really don’t.

There. That’s better. Hopefully that will, as it did last time, serve as a shield against the “shill” argument, which is among the frequent accusations I hear whenever I venture into this particular topic area. So, as I did back in 2008, I just thought I’d clear that up right away in order (hopefully) to preempt any similar comments after this post. Unfortunately, as I have known for a long time, I’m sure someone will probably show his or her lack of reading comprehension and post one of those very criticisms of me. It’s almost inevitable, either here or elsewhere. Posting such disclaimers never seems to work against the “pharma shill” gambit when I write about vaccines or dubious cancer cures. Even so, even after nearly ten years involved in skepticism and promoting science-based medicine, hope still springs eternal.

There are two reasons that I think the issue of mobile phones and cancer needs an update on our blog: First, it has been a year and a half since I last wrote about it. At that time I castigated Dr. Ronald B. Herberman, who at that time was director of the University of Pittsburgh Cancer Institute for what I viewed as fear mongering over cell phones and cancer based on at best flimsy evidence. Second, there have been two fairly high profile studies looking at whether there is a link between mobile phone use and cancer. One of these our fearless leader Steve Novella has already discussed, but there was another one that he didn’t see because it didn’t get quite as much publicity, possibly because the corresponding author is based in Korea. I will take this opportunity to discuss them both.
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Posted in: Cancer, Clinical Trials, Public Health

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The End of Chiropractic

An article written by 3 chiropractors and a PhD in physical education and published on December 2, 2009 in the journal Chiropractic and Osteopathy may have sounded the death knell for chiropractic.

The chiropractic subluxation is the essential basis of chiropractic theory. A true subluxation is a partial dislocation: chiropractors originally believed bones were actually out of place. When x-rays proved this was not true, they were forced to re-define the chiropractic subluxation as “a complex of functional and/or structural and/or pathological articular changes that compromise neural integrity and may influence organ system function and general health.” Yet most chiropractors are still telling patients their spine is out of alignment and they are going to fix it. Early chiropractors believed that 100% of disease was caused by subluxation. Today most chiropractors still claim that subluxations cause interference with the nervous system, leading to suboptimal health and causing disease.

What’s the evidence? In the 114 years since chiropractic began, the existence of chiropractic subluxations has never been objectively demonstrated. They have never been shown to cause interference with the nervous system. They have never been shown to cause disease. Critics of chiropractic have been pointing this out for decades, but now chiropractors themselves have come to the same conclusion. (more…)

Posted in: Chiropractic

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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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The Mammogram Post-Mortem

The Mammogram Post Mortem
Steve Novella whimsically opined on a recent phone call that irrationality must convey a survival advantage for humans. I’m afraid he has a point.
It’s much easier to scare people than to reassure them, and we have a difficult time with objectivity in the face of a good story. In fact, our brains seem to be hard wired for bias – and we’re great at drawing subtle inferences from interactions, and making our observations fit preconceived notions. A few of us try to fight that urge, and we call ourselves scientists.
Given this context of human frailty, it’s rather unsurprising that the recent USPSTF mammogram guidelines resulted in a national media meltdown of epic proportions. Just for fun, and because David Gorski nudged me towards this topic, I’m going to review some of the key reasons why the drama was both predictable and preventable.  (And for an excellent, and more detailed review of the science behind the kerfuffle, David’s recent SBM article is required reading. http://www.sciencebasedmedicine.org/?p=1926 )
Preamble
In an effort to increase early detection of breast cancer, American women have been encouraged to get annual screening mammograms starting at age 40. Even though mammograms aren’t as sensitive and specific as we’d like, they’re the best screening test we have – and so with all the caveats and vagaries associated with what I’d call a “messy test,” we somehow collectively agreed that it was worth it to do them.
Now, given the life-threatening nature of breast cancer, it’s only natural that advocacy groups and professional societies want to do everything in their power to save women from it. So of course they threw all their weight behind improving compliance with screening mammograms, and spent millions on educating women about the importance of the test. Because, after all, there is no good alternative.
However, the downside of an imprecise test is the false positive results that require (in some cases) invasive studies to refute them.  And so this leaves us with 2 value judgments:  how many women is it acceptable to harm (albeit it mildly to moderately) in order to save one life? Roughly, the answer is a maximum of 250 over 10 years (I came up with that number from the data here: http://www.sciencebasedmedicine.org/?p=565 if as many as half of women receive a “false alarm” mammogram over a period of 10 years of testing, and half of those undergo an unnecessary biopsy). And second: how many tests are we willing to do (this is more-or-less an economic question) to save 1 life? The answer is roughly 1900.
So when the USPSTF took a fresh look at the risks and benefits of mammography and recommended against screening average risk women between 40-50 (and reducing mammogram frequency to every other year for those over 50), what they were saying is that they would rather injure fewer women and do fewer costly tests for the trade off of saving fewer lives. In fact, their answer was that they were willing to perform 1300 mammograms to save 1 life, not 1900 (as has been our standard of care).
This value judgment is actually not, in and of itself, earth shattering or irresponsible. But it’s the societal context into which this judgment was released that made all the difference.
1. Timing Is Everything: Or, why not to bring a party hat to a funeral
First of all, it’s almost amusing how bad the timing of the USPSTF guidelines really were. The country was in the midst of trying to pass our country’s first serious healthcare reform bill in decades (at least, the house reform bill was being voted upon the week that the USPSTF guidelines were released) and opponents of the bill had already expressed vehement concern about arbitrary government rationing of healthcare services.
What worse time could there have been to announce that a government agency is (against the commonly held views of the rest of the medical establishment) recommending reduction in frequency  of a life-saving screening test for women? The fact that the guidelines leader said she hadn’t thought about the greater context when she scheduled the press release is quite astonishing. On the one hand, I suppose it shows how disconnected from potential political bias the workgroup really is. On the other hand, it is violates Public Relations 101 so completely as to call into question the judgment of those making… er… judgments.
2. You Can’t Replace Something With Nothing: Or How To Take Scissors From A Baby
Let’s just say for a moment that we all agree that mammograms aren’t the greatest screening test for breast cancer. They’re rather expensive, and wasteful perhaps one might even argue that in a healthcare system with limited resources, one healthy woman’s screening test is another woman’s insulin.  But – it’s all we have. And they do save lives… occasionally.
Anyone who’s seen a child pick up something harmful realizes that the only way to take it from them without tears is to replace it with something harmless. You can’t just take away mammograms from women who have come to expect it, without offering them something more sensible. If there is nothing, then I’m afraid that discontinuing them will result in considerable outrage which you may or may not wish to engage. Given the size and power of the breast lobby – I’d say it’s pretty much political suicide.
3. Know Your Opposition: Or Don’t Bring A Knife To A Gun Fight
And that brings me to point #3. The breast cancer movement is one of the most powerful and successful disease fighting machines in the history of medicine. And bravo to all the women and men who made it such a visible disease. The amount of funding, research, and PR that this cancer gets is astounding – it dwarfs many other worthy diseases (like pancreatic cancer or lymphoma), and is a force to be reckoned with.
Which is why, before you undermine a cherished tenet of such a group, you take a long hard look at what you’re going to say… Because it will be shouted from the hilltops, scrutinized from every conceivable angle, and used to rally all of Hollywood, the medical establishment, and everyone in Washington to its cause. Yeah, you better be darn sure you’re “right” (whatever that means in this context) before attempting to promote a service cut back to this group.
4. Know Who You Are: Or Unilateral Decision Making Is Not A Great Idea – Especially For Government
And finally, it’s important not only to know who you’re dealing with, but to know your mission in society so you can be maximally effective. The US government exists to honor the will of the people and serve its citizens. The best way to do that is to listen to them carefully, engage in consensus-building, and try to be a good steward of resources. When government behaves in ways counter to our expectations, it provokes some legitimate negativity.
So, for example, when a small group of civil servants hole themselves up in a room to create guidelines that will potentially take preventive health services away from women – resulting in a larger number of deaths each year… and they don’t invite input from key stakeholders, and announce their views in the midst of a firestorm about “rationing”
In summary
The new USPSTF guidelines for mammogram screenings debacle serves as a perfect public relations case study in what not to do in advancing healthcare reform. It was the perfect storm of high profile subject, bad timing, poor argument preparation, and lack of back up planning. Though we could have had a rational discussion about the cost/benefit analysis of this particular screening test, what we got instead was the appearance of a unilateral rationing decision by an out-of-touch government organization, devaluing women to the point of death. Throw that chum in the water of human frailty and you’ll get the same result every time: a media feeding frenzy that makes you regret the moment that guideline development became a twinkle in your task force eye.

Steve Novella whimsically opined on a recent phone call that irrationality must convey a survival advantage for humans. I’m afraid he has a point.

It’s much easier to scare people than to reassure them, and we have a difficult time with objectivity in the face of a good story. In fact, our brains seem to be hard wired for bias – and we’re great at drawing subtle inferences from interactions, and making our observations fit preconceived notions. A few of us try to fight that urge, and we call ourselves scientists.

Given this context of human frailty, it’s rather unsurprising that the recent USPSTF mammogram guidelines resulted in a national media meltdown of epic proportions. Just for fun, and because David Gorski nudged me towards this topic, I’m going to review some of the key reasons why the drama was both predictable and preventable.  (And for an excellent, and more detailed review of the science behind the kerfuffle, David’s recent SBM article is required reading.)

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Posted in: Cancer, Public Health, Science and the Media

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Midwives and the assault on scientific evidence

The new mantra of midwives and their advocates is “evidence based practice.” Lamaze, the childbirth education organization has changed the name of their blog to “Science and Sensibility” emphasizing the importance of science and promising:

Lamaze education and practices are based on the best, most current medical evidence available, and can help reduce the overuse of unnecessary interventions while improving overall outcomes for mothers and babies.

But midwives and childbirth educators like Lamaze have a problem. The scientific evidence often conflicts with their ideology. They could address this problem in several ways. Midwives could modify their specific ideological beliefs on the basis of scientific evidence. Childbirth educators could question whether ideology has had an inappropriate impact on the promulgation and validation of their recommendations. Both those approaches would involve a threat to cherished beliefs. They, therefore, have taken a different approach. They’ve tried to justify ignoring scientific evidence.

As midwives Jane Munro and Helen Spiby have documented in The Nature and Use of Evidence in Midwifery, the first chapter of their book Evidenced Based Midwifery, midwives were initially enthusiastic about basing clinical practice on scientific evidence. That’s because they had long told each other that midwifery was “science based” while obstetrics was not:

At the beginning of the evidence based practice movement, much of the midwifery profession responded enthusiastically to the potential for change… Evidence based practice was seen to be offering a powerful tool to question and examine obstetric-led models of care that had dominated the previous decades. The results of such examination could have meant ‘starting stopping’ the unhelpful interventions that had embedded themselves in common practice …

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Posted in: Obstetrics & gynecology

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