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No Evidence That Sitting Is a Major Cause of Low Back Pain

doi: 10.1097/01.BACK.0000605124.49244.2d
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Here are three assertions that back care providers often offer to patients with back pain:

  • Prolonged sitting is an important cause of low back pain.
  • Healthcare providers can advise patients on appropriate sitting postures.
  • Attention to the ergonomics of sitting and chair selection can prevent back pain.

Yet none of these presumed pearls of wisdom finds much support in the scientific evidence, as BackLetter articles have pointed out for years. Various studies have documented that the relationship of sitting and back pain is tenuous at best. That it is difficult to even define “good” sitting posture—since humans don't generally maintain a single sitting posture for hours on end. And claims that proper sitting and chair selection prevent back pain are largely speculation.

One might be tempted to call the above-mentioned statements “myths” at this point—though one has to keep an open mind about future research developments. This is a complicated area of study. There are certainly plenty of people—with various spine conditions—who are intolerant of prolonged sitting. And there may be as yet unidentified subgroups among whom certain sitting postures might help prevent back pain or its recurrence.

However, in the meantime, there does not appear to be any smoking gun connecting sitting to the development of low back pain. Yet many patients come away from back care consultations convinced that sitting is harming their spines—and raising the risk of a lifetime of chronic pain. Based on the evidence to date, these are needless worries. People with back pain should key on other issues.

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Massive Review of Systematic Reviews

Researchers from Australia and Germany recently performed a major review of systematic reviews on the role of physical exposures and posture in low back pain.

Christopher T.V. Swain, PhD, of Australian Catholic University and colleagues screened 4285 publications and identified 41 systematic reviews that were included in their final analysis. These included reviews of the influence of spine postures or physical exposures on low back pain symptoms—as well as those assessing the association with other outcomes, such as medical consultation and work absence. These reviews reported on data collection from more than one million subjects.

The researchers employed the AMSTAR criteria to address the quality of the systematic reviews and the classic Bradford Hill criteria to assess potential causality.

The evidence was clear: “Despite the availability of many reviews, there is no consensus regarding causality of physical exposure to LBP [low back pain]. Association has been documented but does not provide a causal explanation for LBP.”

In particular, Swain and colleagues found no compelling evidence of a relationship between prolonged sitting and low back pain. (See Swain et al., 2019.)

“Despite a growing body of evidence linking sitting to other negative health effects, when it comes to back pain sitting does not appear to be a risk factor,” said senior author Daniel Belavy, PhD, in a statement from Deakin University, where he leads the Spine Research Group.

“So while you may get muscle tightness when you sit for a long time, sitting itself doesn't actually damage the spinal structures directly,” he added.

The review did find an association between both heavy physical work and lifting with low back pain, but the nature of these associations was not clear.

“Both of those things might sound the same, but it's one thing to find an ‘association’ and quite another thing to prove ‘causality’,” he said.

“Studies on ‘causality’ are few and far between because they are harder to do. So it's important we keep working to better understand the mechanisms behind lower back pain,” according to Belavy.

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Important Message for Patients and Healthcare Providers

In a separate email, Belavy suggested it is important to get accurate messages about postures/physical exposures and low back pain out to patients and healthcare providers—and quell unnecessary anxieties about sitting.

“I think it is important where there are misunderstandings or misconceptions to resolve those, especially if these lead to harms to patients, costs to healthcare systems, or productivity losses,” he commented.

“When it comes to sitting, I think a more refined understanding of sitting and the spine is important: sitting is not going to cause you to ‘hurt’ your back. Sure, you may get some soreness if you sit for prolonged periods and have a sub-optimal workplace setup, but then resolving this (breaks from sitting, a more mobile chair/back rest, updated workplace setup), will help,” Belavy explained.

“Alternatively, there are people with existing back problems where sitting may exacerbate the pain; this is another consideration. But, sitting itself, it not going to “cause” people to injure their backs. If one thinks about it, the loads going through the spine and the positions the joints are in in sitting are quite OK: sitting is not (for the spine) a ‘risky’ activity,” he added.

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Sitting and a Biomedical View of Back Pain

A BackLetter editor asked Belavy whether concerns about sitting and back pain are a throwback to the traditional biomedical view of back pain.

“Possibly,” he responded. “What I think plays a role is the simple fact that there are a lot of people out there who, in their desk jobs, after sitting for a while do indeed have a ‘sore’ back. But this kind of soreness usually goes away once people move around for a bit. Alternatively, the workplace setup is important as well: this can influence the static posture in sitting and whether someone gets sore. Also some people with existing back problems do indeed struggle with sitting.”

It is also important to recognize that more than 20% of the general population has some back pain at any given time. And that it is easy to attribute those symptoms to common physical exposures and postures that preceded them.

But those associations fall far short of meeting the nine Bradford Hill criteria for causation: (1) strength [of association]; (2) consistency; (3) specificity; (4) temporality; (5) biological gradient [dose response] (6) plausibility; (7) coherence; (8) experimental evidence; and (9) analogy. (See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1898525/pdf/procrsmed00196-0010.pdf.)

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Ambitious Research Effort

As mentioned above, Swain and colleagues identified systematic reviews and meta-analyses published between January 1990 and June 2018. They found the following:

  • Two systematic reviews and three meta-analyses on spinal curvature and back pain;
  • Eight reviews on standing and back pain;
  • Nine reviews and one meta-analysis on bending and twisting and back pain;
  • Four systematic reviews and one meta-analysis on awkward postures and back pain;
  • Twenty-two reviews on heavy physical work and back pain;
  • Twelve reviews on whole body vibration and back pain; and
  • Seven reviews on sitting and back pain.
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The Evidence on Sitting and Back Pain

The evidence on sitting and back pain was pretty clear. None of the seven reviews found a strong association between sitting and back pain. “All concluded that there was either no, or limited evidence for, an association, a dose-response relationship, or temporality,” according to Swain et al. “Reviews do not support sitting on its own as a factor related to low back pain.”

Overall, Swain et al. concluded that there is consensus regarding the absence of an association between exposure to prolonged or occupational sitting and low back pain.

“With respect to the other physical exposures examined, including sagittal spine curvatures, prolonged or occupational standing, awkward postures, bending and twisting movements of the spine, components of heavy physical work, and whole-body vibration, the evidence was conflicting,” according to Swain et al.

The study and accompanying statement make it clear that the authors are not endorsing prolonged sitting as a healthy activity. There is a variety of evidence that prolonged sitting may be associated with other health problems. And they are certainly not endorsing an inactive lifestyle.

“From other work, we know that general physical activity is important for reducing the risk of back pain,” said Belavy. “Those who are physically active, but not involved in heavy workloads or high-level sporting pursuits, are typically at the lowest risk of experiencing back pain.”

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Getting the Message Out to Patients, Providers, and the General Public

There is a growing sense in spine research that the mere provision of information is not going to change attitudes and behaviors. That there needs to be more aggressive dissemination and implementation of important information.

A BackLetter editor asked Belavy how he would like to get the message out about sitting and back pain

“This comes down to the wider question of “how do we get important public health messages communicated to the right people?” he commented.

Judging from heavy reporting in the mass media, there seemed to be broad interest in this review—and its conclusions.

“This particular finding about sitting and back pain is of wider interest in the general public, hence the popular media interest we had on the study. This is a useful avenue to educate the public: you will reach a proportion of the populace and improve their understanding each time the media communicates the message,” he noted.

Belavy suggested that healthcare providers are another important vector in this dissemination effort.

“I think it is important to educate health care providers more generally about what are indeed risk factors for back pain and, of course, how is back pain most effectively managed. He suggested that clinical guidelines and major reviews (such as the Lancet Series) may play an important role in educating healthcare providers.

“There is also a proportion of health care providers who are outside [major] centers and don't necessarily have the time to pay attention to these communications, given the breadth of conditions they deal with. How do we get key messages to these health care providers? This becomes more challenging: professional development and communications in periodicals that they are more likely to read, are some possible pathways. There will be other pathways,” he observed.

“Even then there are sometimes vested interests that prevent key messages getting across to health care providers. Here I think of professions where a particular treatment X is what this profession does, but this treatment X is not effective for back pain and may be harmful. Yet the profession's existence is based on treatment X. This is where I think working with insurers and consumers may be more beneficial,” according to Belavy.

Disclosures: None declared.

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Reference:

Swain CTV, et al No consensus on causality of spine postures or physical exposure and low back pain: A systematic review of systematic reviews [published online ahead of print August 13, 2019], Journal of Biomechanics; doi:10.1016/j.jbiomech.2019.08.006.
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