LBP. Cause (Aetiology).
The causes of LBP are multifactorial and ill understood. It is suggested (Adam et al.2002) that there is a need to integrate the evidence from genetics, biomechanics, biochemistry, cell biology and psychology to construct a comprehensive model.
Twin studies suggest that only 70% of the UK population is liable to LBP (Spector 1999). Other twin studies strongly emphasise the genetic factor in the aetiology of LBP (Battie et al., 2002). Genetics are not a cause of LBP but a risk factor acting through, possibly, spinal configuration or components of the disc composition.
Psycho-social factors, regarded as an important in the large increase in the last 20 years (Waddell 1996), is more a response rather than a cause, resulting increases reporting. Anecdotal evidence from patients with chronic LBP should not be ignored. Although usually unaware of any causative incident, they are fully aware of what makes their symptoms better or worse.
The prevalence and incidence of LBP in populations that do not use Western style upright chairs but other ‘natural’ styles of sitting. which are culturally determined, is very low or nil, suggesting an adverse effect of the use of Western style upright chairs. In Japan, this increases as elements of the population adopt Western chairs (Schlemper 1987).
Nutrition, environment and lifestyle may all play a part in the aetiology of LBP, but the only new factors that might account for the present epidemic is lack of exercise and a sedentary Western lifestyle. Driving, office work, computers and TV, the modern worker spends an increasing amount of time in a chair.
Epidemiological studies of backache prevalence.
The literature on epidemiological evidence is extensive but, in relation to aetiology, confusing due to uncertainties and imprecision in describing reliably the condition that is under review. Low back ‘trouble’ extends from LBP of psycho-genic origin to a midline IVD protrusion causing a corda equina syndrome, which is a surgical emergency. Meta-analysis of systematic reviews, useful for evidence based therapeutics, have to be viewed with caution in extrapolating to clinical conditions. (Furfan et al 2001). I have often seen wrong conclusions in my own field.
A study by the US Department of Health and Human Resources (NIOSH 1997) reviewed a number of factors and the general conclusions seem to suggest that the evidence was contradictory and confusing. There was an emphasis on non-physical psycho-social factors and heavy load handling. Much of the research into the causation of spinal breakdown has concentrated on violent or inappropriate spinal usage afflicting manual workers today and hominins in prehistory (See Origins of lumbar vulnerability→).
In a Swedish review (Linton, van Tulder.2001) of controlled trials of preventive interventions for back pain problems only exercise gave evidence of relatively moderate significance perhaps suggesting that sitting has no influence on LBP. The divergence of the clinical and other evidence from that of some epidemiological studies suggests that the methodology of the latter should be reassessed rather than an immediate conclusion that seating plays no part in the symptomatology of LBP.
Invisibility is possibly due to the universality of the upright sitting posture on chairs becoming a part of the human condition in Western orientated populations, so that it fails to become apparent to recognition in systematic reviews. This impacts on research, where musculo-skeletal funding is minuscule, in spite of the economic, which is about £13billion annually in the UK, and personal cost .