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12 June 2010

Chiropractic Correspondence

I received this email a little while ago.

Hi Gem,

After a heated discussion with my Mom, I cannot convince her that chiropractic doctors are not real doctors and that most of it is a pseudoscience. Do you have any general information or resources you could send me so I can show her? Only if you have time, of course!


Since I've been putting much of what would normally be blogging time into fielding email questions, I might as well make my responses serve double-duty. Here was my response:


If it helps, I understand your situation. As you know, I've been in a similar situation with many close friends and relatives.

I actually used to have chiropractic treatments regularly, and several members of my family still swear by them. My chiropractor was a very nice gentleman, and although I am now convinced that the treatments that I received were bogus (and there is evidence to suggest that he actually put me at greater risk of suffering a stroke), I have no reason to believe that he was consciously committing fraud.

Simon Singh, a British journalist for The Guardian, was sued last year by the British Chiropractic Association for libel, after he called their treatments "bogus". You can find his article, with citations added, here. It's a short read, but quite good. As Professor Frank Frizelle quipped, "Let's hear your evidence not your legal muscle."

[Edit: Apparently that link no longer works. However, since Singh won the libel case, the Guardian reinstated the original article, so you can read that instead.]

Skeptoid is also a very good resource. Brian Dunning is lively, and he cites his articles/podcasts well. In fact, this transcript might make an excellent starting point, as it gives a good overview of the subject.

Finally, Quackwatch is always a good resource when looking into medical claims. A quick search of "chiropractic" turns up nearly 200 articles.

The unfortunate truth is that it is unlikely that any amount of evidence will convince a person who isn't interested in the evidence, and it's likely that most people won't be. As Jonathan Swift is reputed to have said, "You cannot reason a person out of a position he did not reason himself into in the first place." If your main goal is convincing someone, it's often best not to get into a direct confrontation, as this will frequently just put them on the defensive and force them to rationalise away any evidence that you care to present. If you want to avoid conflict, it's often best to just present the evidence a little bit at a time, and not push the other person too hard. If they're honestly interested in figuring out what is true (and this won't be everyone), then they'll eventually start to pay attention, and even ask questions.

To be fair, I don't always follow my own advice, here. I can be a rather reckless conversationalist at times. There are things that I'm good at, but being careful or politically expedient isn't always one of those things. But depending on what you want, framing the issue can be very important.


Honestly and openly admitting the edges of your own expertise can go a long way, as well. There's never any harm in looking things up! (But it is important to be sure that you're not just looking for confirmatory evidence, as well; make sure that you're looking somewhere reputable!)

My wife is calling for me to come to bed, so I'll have to leave it there. Best of luck!


PS: Chiropractic doctors are "real doctors", if by "real" you mean that they are allowed to put "Dr." in front of their name. But so are dentists. They are most emphatically not medical doctors or physicians. They do not attend medical school. It's sometimes important to clarify what you mean, here.


  1. PART 1 of 3
    Interesting but not completely accurate. Using the term 'chiropractic' rather than 'cervical manipulation' when referring to adverse events is akin to using the term 'medicine' when referring to deaths due to surgical complications - it's a deliberate misrepresentation. The intention is to create fear about a group rather than rational discourse about the actual procedure purported to increase risk of adverse events.

    In other posts I've noticed on your blog, you discuss the 'evidence' for the dangers of chiropractic (not cervical manipulation – see above) and state "I'm not cherry-picking". I disagree and believe these articles are 'cherry-picked', just as they are on sites such as Quackwatch and other ‘skeptic’ sites. Simply inputting a Boolean request into Pubmed and taking the first studies you see is not critical appraisal, nor is counting the number of studies (argument by repetition). Being the most or the first study is irrelevant quality. The studies you cite on this blog are those commonly cited and they are case studies or case series (despite the contention of Dr. Ernst that his paper is a systematic review – simply reading the paper will confirm this). Case studies are just well reported anecdotes and the plural of anecdote is not data. Although they have their place in the research evidence hierarchy, case studies are not capable of determining causation of benefit or harm.
    In addition, the often-quoted 'study' by Dr. Ernst is misleading at best and deliberately maligning at worst, as most of the practitioners linked to adverse events were not chiropractors although they were labeled as such (Terret, 2001). The question a true skeptic should ask is, “Why would someone label a practitioner a chiropractor when they were, in fact, not?” More recent research suggests that stroke following cervical manipulation is more likely in non-chiropractors than chiropractors (Reuter, et al., 2006 J Neurology - This is not apparent, however, from reading the abstract. The abstract gives the impression that this was a study of chiropractors, when in fact it was not. A skeptic would read the entire article and notice on page 727 that of the 31 identified strokes over a three year period only 13% (4/31) were attributed to chiropractors. However, 16% (5/31) were attributed to physiotherapists, 3% (1/31) to a neurologist, 3% (1/31) to a homeopath, 6% to a GP, and 58% (18/31) were attributed to orthopaedic surgeons. A skeptic would ask, “Why is this titled ‘Vertebral Artery Dissections after Chiropractic Neck Manipulation in Germany over three years’ when the majority of strokes occurred at the hands of medically trained practitioners (68% 21/31) and physiotherapists?” and “Is this title and abstract deliberately misleading?” The data gathered in the article seems to support that if you require cervical spine manipulative therapy, go to a chiropractor, as they appear to be associated with less adverse events than medical providers or physiotherapists. This is also why one must critically appraise an entire health research study and not glance at abstracts that support a preconceived notion.


  2. PART 2 of 3
    There have been few large-scale well-designed studies looking at the extremely rare phenomenon of vertebral basilar artery dissections (VBA or VAD) following cervical manipulation. One of the most recent, and well-designed, large-scale population studies was done by Cassidy et al (2008), and shows no increased risk compared with medical care (see Cassidy et al., 2008 - ). This suggests a temporal relationship between the incidence of VBA’s and manipulation rather than a causal one. A skeptic might ask, “Why has this study not been presented along side simple case studies of harm and articles that clearly misrepresent the data they’ve collected?” Perhaps because it does not fit a predetermined narrative – only one possible explanation, I’m open to others that satisfy Occam’s razor.
    Chiropractic care, with an obvious emphasis on manipulative therapy, for spine-related musculoskeletal complaints has been studied more than any other therapeutic modality. No study to date has shown manipulative therapy to be less effective than standard/usual care, suggesting it is at least as good and valid an option for patients with spinal pain complaints as medical care. However, when clinical practice guidelines are applied, it appears that chiropractic care fairs much better than usual care (see Bishop et al. 2010 - ).

    Finally, an argument I've read on various pages of your blog goes something like, "The study was positive for chiropractic, but the study was done by a chiropractor". This is argument by innuendo - leading the reader to assume the study if flawed because it was a chiropractor that performed it rather than a rational discussion of the actual flaws of such a study. Further, this argument implies that others are more reliable (i.e. a 'real' doctor), which is a tacit appeal to authority rather than a critical appraisal of the research. The use of the "not a ‘real’ doctor" moniker is an appeal to ridicule – another informal fallacy.


  3. PART 3 of 3
    As it turns out, most research into chiropractic therapies is performed by chiropractors just as cardiologists perform most cardiac research. I wouldn’t expect computer scientists to do health research – a very different skill set is required. However, the chiropractors publishing these studies generally have acadaemic degrees, (i.e. M.Sc., Ph.D.) or other professional degrees (i.e. M.D., D.O.) and in some cases all three. This is similar in other disciplines; those doing research tend to have additional training beyond that of a clinician or technician. I find the argument that "chiroprators can't be trusted to do chiropractic research" the most disingenuous and intellectually lazy as it requires no critical thought and does not assess 'why' a research article is flawed but rather appeals to the majority belief (argumentum ad populum). In science it is the quality of the argument that is to be judged NOT the person making the argument as is rampant on so-called skeptic boards. This is why many genuine research scientists think of 'skeptics' as strict adherents of orthodoxy rather than bona fide critical thinkers.

    Of course, this is not always the case. One can be skeptical without being cynical - but there is a very fine line between the two. One is helpful and the other is self-indulgent. The key questions one should ask to determine if you are a skeptic or cynic are:
    1.a. Is there any level of evidence that would change my opinion?
    1.b. Is that level of evidence greater than for other claimants?
    2. Do I question my own beliefs when I ‘Question Everything’?
    3. Do I entertain the notion that I may be wrong?

    I must apologize for the length of this comment – it is a bit self-indulgent. For the record, if you hadn't already assumed it, I am a chiropractor...and a skeptic. I do not speak for all chiropractors, but I do represent the views of a substantial number of them.

    Thank you for your time.

  4. Hey, Anon.

    Thanks for your comments!

    As my response also exceeds the Blogger-imposed limit, you can find it here.

    All the best.

  5. This is a good conversation. Anon, do you have a response?

  6. Good facts Spurll. Way to not back down.