5The Epidemiology of low back pain
Section snippets
Incidence
Estimating the incidence of low back pain is problematic as the cumulative incidence of first-ever episodes of low back pain is already high by early adulthood [19] and symptoms tend to recur over time [20]. In addition, longitudinal studies, which measure incidence, are more expensive than cross-sectional studies, which measure prevalence. As a result, there is a significant amount of literature on the prevalence of low back pain, but much less information on low back pain incidence and
Remission
For estimating the burden of disease in GBD 2005, remission is defined as the rate at which people stop having the disease or condition, and is expressed as an annual hazard rate to recover from the disease. In many instances, people with activity-limiting low back pain will go on to have recurrent episodes [32], [33], [34], [35], [36] that may be longer in duration and associated with greater disability [37]. Consequently, the course of low back pain is increasingly viewed as a chronic,
Duration
We conducted an abbreviated search of the literature and found a small number of cohort studies that estimated low back pain duration. Similar to remission, we found the only useful studies were health facility- or clinic-based. Again, there was substantial heterogeneity between studies. Many of the studies reported the proportion of people with pain at a certain time point , which is reported on in the remission section above. Van den Hoogen found the median duration of pain from the index
Recurrence
The natural history of low back pain has been observed to be extremely variable and may last a few days or persist for many years [49]. Most commonly, people who experience activity-limiting low back pain lasting more than 1 day go on to have recurrent episodes [32], [33], [34], [36], [50]. Wasiak et al. (2006) found that low back pain recurrence contributed disproportionately to the burden from non-specific work-related low back pain [37]. They found that those people who had recurrences had
Prevalence
Comparing the prevalence of low back pain between populations and over time is challenging due to considerable methodological heterogeneity across studies and difficulties in obtaining true population estimates. Having said this, there is considerably more literature on the prevalence of low back pain compared with incidence, remission and duration. Much of the methodological variation relates to the case definition and recall period, the age and sex distributions, the representativeness of the
Mortality
There are few studies that have investigated whether there is an association between back pain and mortality. Zhu et al. found those with back pain had a greater overall mortality risk (hazards ratio = 2.03; 95% confidence interval: 1.14–3.60) and a greater risk for death from coronary heart disease than those without back pain [94]. In two further studies, no relationship was found between mortality and back pain [95], [96]. Further research is needed in this area.
Causes
Studies suggest that low back pain may arise from any one of a number of anatomical structures, including bones, intervertebral discs, joints, ligaments, muscles, neural structures and blood vessels [97]. In a minority of instances, approximately 5–15% [97], [98], [99], low back pain can be attributed to a specific cause such as an osteoporotic fracture, neoplasm or infection [97], [100]. For the remaining 85–95% of cases, the specific cause of low back pain is unclear [97], [100].
The search
Risk and prognostic factors
Risk factors are variables associated with an increased risk of disease. Examining risk factors for a particular disease may involve measuring the occurrence of disease in two or more groups of people who have experienced different levels of exposure. While research into risk factors for low back pain is often challenging due to heterogeneity across research methods, case definitions and study populations, it is clear there are a number of environmental and personal factors that influence the
Impacts and outcomes
Low back pain has a substantial impact on individuals and their families, communities, health-care systems and businesses. This includes pain, activity limitations, participation restrictions, career burden, use of health-care resources and financial burden. Impacts and outcomes from low back pain are likely to vary significantly between and within populations depending on socio-economic status, general access to health services, occupational distribution, pain perception and other factors that
Conclusions
It is clear that low back pain is an extremely common problem, which most people experience at some point in their life. Most cases run a chronic–episodic course. It has a huge impact on individuals, families, communities, governments and businesses throughout the world. The GBD 2005 is currently making estimates of the global burden of low back pain in relation to impairment and activity limitation. Results will be available in 2011. Using a standardized case definition for low back pain in
Acknowledgments
We would like to thank the Bill and Melinda Gates Foundation (DH) and the National Health and Medical Research Council (DH) for their financial support. Thank you to Professor Lyn March and Professor Anthony Woolf for their leadership on the GBD 2005 Musculoskeletal Group. Thank you to Professor Theo Vos for his technical support on the GBD 2005 Study. We are also very grateful for the cooperation of the following individuals who provided us data on request: Professor Fereydoun Davatchi; Dr
References (152)
- et al.
Low back pain in rural Tibet
Lancet
(2003) - et al.
Prevalence of low back pain in three occupational groups in Shanghai, People's Republic of China
Journal of Safety Research
(2004) - et al.
Measuring the global burden of low back pain
Best Practice and Research. Clinical Rheumatology
(2010 Apr) - et al.
The course of low back pain in a general population. Results from a 5-year prospective study
Journal of Manipulative and Physiological Therapeutics
(2003 May) - et al.
Can rate of recovery be predicted in patients with acute low back pain? Development of a clinical prediction rule
European Journal of Pain
(2009 Jan) - et al.
Changes in the mechanical properties of the trunk in low back pain may be associated with recurrence
Journal of Biomechanics
(2009 Jan 5) - et al.
The Nordic back pain subpopulation program: a 1-year prospective multicenter study of outcomes of persistent low-back pain in chiropractic patients
Journal of Manipulative and Physiological Therapeutics
(2005 Feb) - et al.
Low back pain in Australian adults: prevalence and associated disability
Journal of Manipulative and Physiological Therapeutics
(2004 May) - et al.
Low back pain in schoolchildren: occurrence and characteristics
Pain
(2002 May) - et al.
Pain in older adults: a prevalence study in the Mediterranean region of Catalonia
European Journal of Pain
(2007 Jan)