Sometimes it’s unclear why you get LBP. You may simply wake up with it, or it could begin without warning while you’re reading the weekend newspaper. Even if you suspect a particular activity is responsible, the timing may not fit. Remember too that LBP is recurrent by nature, with subsequent episodes sometimes occurring for no apparent reason (like a cold!). In all of these cases, LBP is a bitter pill to swallow, and you will likely find yourself asking, “Why did this happen to me?”.
At other times LBP is easily attributable to a particular movement or action. One moment you’re perfectly fine, and the next you’re crying out from the pain in your back. It might be you were lifting something heavy, like a child, or a wheelbarrow full of cement. Or perhaps you were simply bending over to replace a bin liner! It could also begin gradually during an extended activity like gardening, or working around the house. And while LBP is always unpleasant, I personally think it’s easier to understand in cases such as these, where there is a clearer mechanism of onset.
However, even when it’s obvious what has triggered your LBP, this doesn’t mean it makes sense. Take replacing the bin liner for instance. How can this cause LBP? Certainly, anyone who hurts themselves during such a trivial task, could be forgiven for thinking the back is fragile. However, contrary to what these people might believe, the back is not weak. During university I worked as an anatomy tutor, and also did some dissection work, helping to prepare the prosections. Anyone who has worked directly with prosections of spines and backs will tell you how strong these structures are. The bones (vertebrae) and joints of your lower back are supported by tough fibrous connective tissue and large muscles. Not what I would consider fragile! 😊
And yet, I seem to treat a disproportionate amount of people, who have ended up with LBP after an ordinarily harmless movement. Note that I’ve intentionally avoided using the ‘I’ word here. I don’t use the term ‘injury’ in front of most patients, because in these types of cases, it’s impossible to tell if someone presenting with LBP has truly injured themselves (see ‘non-specific LBP’ definition in ‘What is LBP?’). I do know that provided there was no real trauma involved, it’s unlikely there is any significant damage, and that they will probably get better by themselves (again, like a cold!). It may seem like semantics, but words are powerful.
Assuming the back is strong (because it is!), this again begs the question, “Why did I end up with LBP?”. Could it be the cumulative effects from the constant ‘strain’ on these structures? The proverbial straw that breaks the camel’s back? (Awful pun that!) If this is the case, does it mean a person’s occupation is the principal factor involved? Or could it be influenced by other things like a lack of fitness, or even genetics? What does science have to say about this?
A significant amount of research has centred on investigating factors that increase the risk of developing LBP. A reliable risk factor would not only have important implications in terms of the prevention of LBP, but potentially furthering our understanding of its underlying mechanism. The list of risk factors featured in research to date, is long and diverse. Some of these include:
• Presence of co-existing medical conditions (co-morbidities)
• Low educational status
• Low social status
• Participation in vigorous physical activity (not what you might think! 😉)
• Highly monotonous tasks
• Awkward postures
• Specific types of pain behaviour (e.g. catastrophising, pain avoidance etc.)
As you can see some of these risk factors are modifiable. But before you quit your day job, sell your gardening tools, and start studying full-time, you should know that there is still limited evidence supporting any of these risk factors. In fact, a 2014 systematic review, which analysed 41 studies, found no consistent risk factor for first-time LBP, and only a history of LBP as a risk factor for future episodes.1 The biggest issues the authors found with potential risk factors were 1) They hadn’t demonstrated replicability across different studies, and 2) Even if they had, they were only weakly associated with LBP.1
Why bother listing these risk factors if the current balance of evidence doesn’t support them? Because this body of evidence is continually being updated, and therefore likely to change! Research is a collaborative process, and as the study methods of these risk factors continue to improve, this will help fully elucidate their relationships with LBP. Currently, while we may know that they’re related, we may still be unclear on the characteristics of these relationships. As an example, several studies identified associations between LBP and psychosocial factors, however, were unable to determine the direction of these relationships.2,3 In other words, does something like depression cause LBP, or is it the other way around? Another pre-requisite for identifying a risk factor is establishing a causal relationship between LBP and the variable being tested (e.g. depression). Does LBP occur as a result of depression (causation), or is it that people with depression are more likely to have LBP due to some other reason (association)?
So, what does this mean for you? Well, with such a long and diverse list of risk factors, it’s likely you’ll identify with at least a few. Broadly speaking most people either do sedentary (sitting at a desk), or physical work. Another systematic review, this time analysing 18 studies, examined the effects of mechanical spinal load on LBP.4 It found strong evidence that sitting, prolonged standing and walking were not associated with LBP. Woohoo! Great news if you’ve ever done any of these things! 😉 This same review found conflicting evidence that heavy physical work, as well as working with one’s trunk in a bent and/or twisted position, was associated with LBP. Even with this study’s limitations, what these results possibly suggest is that while there is still no clear evidence that demanding physical work is a risk factor for LBP, it may yet prove significant, and therefore warrants further investigation. What about the role of genetics then? Twin studies are a common means of studying LBP risk factors since they make it easier for researchers to determine environmental influences (given identical twins have virtually the same DNA, any differences between them will be environmental). While a clear cause-effect relationship between genetics and LBP has not been determined, there is some evidence that genetics is a significant contributor to this condition (especially the chronic type).5
I’ve only provided a taste of the research that’s out there when it comes to LBP risk factors. However, these studies are representative of the research body as a whole. Rather than feeling frustrated with a lack of conclusive risk factors, I would encourage you to draw confidence from the fact that whatever your profession (or pastimes) may be, they are unlikely to be THAT influential in causing LBP. If these risk factors were extremely influential, it is probable the evidence would be clearer by now. This is great news if you’re a brick layer or a labourer who is worried that their career choice has doomed them to LBP! Instead, after decades of research there is still no consistent risk factor for first-time LBP. And even if a reliable risk factor is identified, it probably won’t be that significant, as LBP is much more likely to be caused by a myriad of factors (multifactorial).6
On the next page we’ll take a look at some of the possible causes of LBP.
• LBP can occur for no apparent reason (either suddenly or gradually)
• LBP can also occur during a particular movement (e.g. lifting) or activity (e.g. gardening)
• Despite popular opinion amongst people with LBP, the lower back is strong!
• There are many, diverse risk factors that have been identified for LBP, although there is currently limited scientific evidence to support any of them
• One large study in 2014 found no consistent risk factor for first-time LBP, and only a history of LBP as a risk factor for future episodes.
• There is limited evidence linking LBP to a sedentary lifestyle (good news if you’re an office worker!)
• There is conflicting evidence linking LBP to demanding physical work (reasonably good news if you’re a tradesman!)
• Genetics is likely a significant contributor to severe and chronic LBP
• The evidence is likely to change with further research
• Future risk factors probably won’t be that significant by themselves, since LBP is most likely caused by many different factors (multifactorial)
1. Taylor JB, Goode AP, George SZ, Cook CE. Incidence and risk factors for first-time incident low back pain: a systematic review and meta-analysis. Spine J. 2014;14(10):2299-2319. doi:10.1016/j.spinee.2014.01.026.
2. Lang J, Ochsmann E, Kraus T, Lang JWB. Psychosocial work stressors as antecedents of musculoskeletal problems: A systematic review and meta-analysis of stability-adjusted longitudinal studies. Soc Sci Med. 2012;75(7):1163-1174. doi:10.1016/j.socscimed.2012.04.015.
3. Hoy D, Brooks P, Blyth F, Buchbinder R. The Epidemiology of low back pain. Best Pract Res Clin Rheumatol. 2010;24(6):769-781. doi:10.1016/j.berh.2010.10.002.
4. Bakker EWP, Verhagen AP, van Trijffel E, Lucas C, Koes BW. Spinal Mechanical Load as a Risk Factor for Low Back Pain. Spine (Phila Pa 1976). 2009;34(8):E281-E293. doi:10.1097/BRS.0b013e318195b257.
5. Ferreira PH, Beckenkamp P, Maher CG, Hopper JL, Ferreira ML. Nature or nurture in low back pain? Results of a systematic review of studies based on twin samples. Eur J Pain. 2013;17(7):957-971. doi:10.1002/j.1532-2149.2012.00277.x.
6. Delitto A, George SZ, Professor A, et al. Low Back Pain: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability, and Health from the Orthopaedic Section of the American Physical Therapy Association Associate Professor in Physical Therapy and Orthopaedic Surgery, Program in Physical Therapy HHS Public Access. Man Ther. doi:10.2519/jospt.2012.42.4.A1.