Is Back Pain Killing Us?

Around 1.600 words, estimated reading time: 7-8 min.

The question might seem overdramatic.

And yet, it is raised by an academic paper published earlier this year in the very serious European Journal of Pain (vol. 21, issue 5) titled “Is This Back Pain Killing Me?”

A preview of the paper is accessible online and the University of Sidney website has a short discussion by one of the lead researchers and senior author, Associate Professor of physiotherapy Paulo Feirrera.

The research points at a disturbing connection between back pain and mortality, summed up as followed by Prof. Ferreira:

Our study found that compared to those without spinal pain (back and neck), a person with spinal pain has a 13 percent higher chance of dying every year. This is a significant finding as many people think that back pain is not life-threatening.

The Study in a nutshell

The study followed 4391 elderly  Danish twins over 70 years old for 17 years. At the beginning of the study, in 1997, participants were aged 73 and older. Some participants 70 years old or older were added in 1999 and 2001. Participants were followed until their death or the termination of the study (2014). Using twins allowed to control genetic factors and the study also controlled for two other confounders (baseline functional abilities and depressive symptoms). Prevalence of back pain was established via self-reporting (interviews) which also served to assess depressive symptoms. Functional abilities were evaluated through physical tests such as walking at a brisk pace under various weather conditions.

The motivation for the study is spelled out in the introduction of the EJP paper as follows (where […] signals the omission of a reference):

Although the burden of spinal pain as a musculoskeletal condition is firmly established […] little is known as to whether spinal pain potentially reduces life expectancy. With an ageing population, this is relevant as it is well established that chronic […] widespread […], musculoskeletal pain […] and degenerative joint disease such as osteoarthritis […] increase the rate of mortality, yet the relationship between spinal pain and all-cause mortality is unclear […].

The authors also note that previous research seemed to indicate an increased risk of mortality in adults older than 70 years reporting lower back and neck pain, but that studies including younger adults were more uncertain — some showing a possible link, others none.

The study, therefore, followed a population in which the association between back pain and mortality is in fact already well-known. Its goal was to find a causal relationship between the two, and its finding was negative. In fact, for this population, the answer to the titular question is ‘probably not and the Conclusions section of the abstract of the EJP paper leaves no doubt about this (our emphasis):

Older people reporting back pain have a 13% increased risk of mortality per year lived but the connection is not causal. We found no [causal] association between spinal pain and cardiovascular-specific mortality. The influence of shared familial factors is unlikely.

Some context

The first author of the Danish twins study is a Ph.D. student whose research was funded by an advocacy group for chiropractic and osteopathic medicine, and one of the Danish co-authors belongs to an institute that teaches chiropractic manipulation alongside biomechanics. The connection with osteopathic medicine is critical to understand the purpose of the study. Compared to traditional Western medicine, osteopathic medicine has a short but interesting history which contributes to explaining the question raised by the Danish twins study.

Osteopathic medicine developed at the end of the 19th century,  in reaction to the rapidly increasing use of (often unsafe) chemicals and surgical procedures. The founder of osteopathy was American physician Andrew Taylor Still, who had lost his family to spinal meningitis in 1864. At a time where infectious deceases and asepsis were poorly understood (Louis Pasteur published his breakthrough studies in The Lancet in 1867) A.T. Still could blame traditional Western medicine as a whole, and he came to believe that health is the natural state of the human body and that the object of medicine is to restore health rather than fighting illness — in his words: “To find health should be the object of the doctor. Anyone can find disease.”

A consequence of A.T. Still’s belief was the substitution of intangible principles to evidence-based ones in the practice of medicine. In fact, early osteopaths avoided the criminal charge of illegal exercise of medicine by claiming that their discipline was not based on evidence and thus distinct from medicine. To evidence based-approach, they substituted intangible principles and deduction from these principles. The core tenet of osteopathy is the Vertebral Subluxation Hypothesis formulated by A.T. Still, that ascribes the cause of organic diseases to ‘subluxations’ (misalignment) of vertebrae disrupting ‘nerve flow’, which entails that chiropractic manipulation is capable of curing conditions that traditional Western medicine does not consider musculoskeletal in nature. Since its formulation, the hypothesis has received different interpretations as an attempt to circumvent the fact that it has never been substantiated empirically.

Since the 1960-70s, osteopaths have been divided into physician osteopaths and non-physician osteopaths. The first group is educated almost exclusively in the United States in schools of osteopathic medicine, the first of which opened in 1966. These schools pay lip service to the legacy of A. T. Still, and adopt a pragmatic attitude towards traditional Western medicine. Consequently, their curriculum is indistinguishable to their non-osteopathic counterparts, but for the addition of osteopathic manipulation to the general curriculum. By contrast, non-physician osteopaths are educated worldwide in academic and para-academic institutions whose stance towards the teaching of A.T. Still vary from the same pragmatism as U.S. osteopathic medicine to a rejection of traditional Western medicine in favor of ‘alternative’ practices.

Although variants of subluxation theory (often under other various scientific-sounding names) remain the rationale for teaching chiropractic manipulation in schools of osteopathic medicine, they still lack any substantial evidential support. While A.T. Still may have seen this as a feature rather than a bug, the advent of evidence-based medicine has made the lack of support for osteopathic manipulation for anything beyond pain relief an issue for physician osteopaths. In fact, outside the U.S. and a handful of other countries, chiropractic manipulation has only gained official recognition by advertising itself as an auxiliary treatment of musculoskeletal issues — that is, as an advanced form of massage therapy — and keeping claims about ‘nerve compression’ between patient and practitioner.

[As an aside, Sweden is an interesting illustration of this. Its local variety of chiropractic manipulation, naprapathy, was founded by yet another U.S. citizen, Oakley Smith. Unlike A. T. Still, O. Smith never completed a formal medical education (he dropped out of Chicago Medical School). Smith also abandoned the study of Osteopathic medicine, founded the National College of Naprapathic Medicine (NCNM) in Chicago, and awarded himself a title of Doctor of Naprapathy. This degree is nowadays recognized by the State of Illinois (and apparently, nowhere else) where it allows opening practices akin to those of dentists (unlike the title of Doctor of Osteopathy that grants the same privileges as medical doctors). The NCNM advertises treatment of chronic pain while cautiously hinting at the ability to do more but avoids any direct claim that naprapathy is anything than an advanced form of massage therapy, a practice mimicked by the Swedish Naprapathy Society  (Svenska Naprapatförbundet) and the (unrelated) Swedish College of Naprapathy (Naprapathögskola).]

So, what of it?

The Danish twins study appears to have been in part motivated by an attempt to establish the effectiveness of osteopathic manipulation beyond pain management. If a causal link between pain and both cardiovascular and all-cause mortality had been found, a rationale for treating pain through manipulation as an alternative treatment to other life-threatening conditions would have been substantiated. But this link hasn’t been found.

The absence of a causal link between pain and mortality is bad news for osteopathic medicine. Treating spinal pain through chiropractic manipulation has likely no direct effect on either cardiovascular deceases or other life-threatening conditions. Hence, there is no validation for the hypotheses underlying osteopathic medicine that most conditions (including life-threatening ones) have their origin in musculoskeletal dysfunction and compressed nerve flow.

Still, spinal pain is a more serious symptom than previously thought. While treating spinal pain cannot directly impact cardiovascular mortality, the authors note that “pain in the spine may be part of a pattern of poor health, which increases mortality in the older population.” Improving health in such a way that would lower the incidence of back pain, would thus also very likely lower the incidence of other life-threatening conditions.

An alternative to the alternative?

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Resistance training is a well-researched alternative to medication and surgery in the treatment of chronic deceases. Unlike chiropractic manipulation, resistance training can claim evidential support. It has long been known to increase bone density and help prevent age-related conditions such as osteoporosis and loss of muscle mass. But there is also mounting evidence that resistance training can actually prevent such chronic diseases as cancer, multiple sclerosis, and Parkinson’s disease. While the research is ongoing, this evidence is solid enough to warrant textbook treatments.

Properly implemented, resistance training can significantly improve health markers such as lean body mass and cardiovascular fitness. And while research in biomechanics indicates that muscular strength does not protect against back and neck pain as well as previously thought, there is more to resistance training than strength training, and adequate resistance training protocols can improve cardiovascular endurance and muscle endurance better than bodyweight aerobics.

The take-home message

Back pain is most likely not going to kill you. It is, however, a symptom of poor health, and preventing its occurrence is a sensible strategy for those who intend to live longer with a better quality of life. As of today, resistance training is one of the best ‘alternative’ to drugs and surgery, both preventively and curatively. In fact, resistance training can readily claim to have the benefits that manipulative medicine has claimed to have but failed to demonstrate.

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