Tuesday March 25 2014
Many cases of back pain have no obvious cause
"Back pain behind 'more disability than any other condition'," ITV News reports after a new study found that the condition may now be the leading cause of disability worldwide.
The study looked at how much disability is caused by lower back pain globally. It found that lower back pain caused more disability than any other condition, affecting nearly 1 in 10 people and becoming more common with increasing age.
The condition was most common in Western Europe, followed by North Africa and the Middle East, and was lowest in the Caribbean and Latin America.
The results of this research – which used data from a large study undertaken in 2010 on the global burden of disease – are likely to be reliable, and its findings will be of concern to health officials.
The study does a good job at highlighting a common but often overlooked condition. Lower back pain is not usually linked to any serious disease, but can be debilitating and emotionally distressing. It can be triggered by bad posture while sitting or standing, bending awkwardly, or lifting incorrectly.
Find out more about how to prevent back pain.
Where did the story come from?
The study was carried out by researchers from a number of academic institutions in Australia, the University of Washington in the US, and the Royal Cornwall Hospital in the UK.
It was funded by the Bill and Melinda Gates Foundation, the Australian Commonwealth Department of Health and Ageing, the Australian National Health and Medical Research Council, and the Ageing and Alzheimer's Research Foundation.
The study was published in the peer-reviewed medical journal, Annals of Rheumatic Diseases.
ITV News, the Daily Express and the Mail Online coverage of the study is fair, although the Express was wrong to class the growing number of people suffering from lower back pain as an "epidemic". Strictly speaking, an epidemic refers to the spread of infectious disease.
But, as the authors point out, back pain is on the rise because of the world's ageing population, a trend that is likely to continue.
What kind of research was this?
This research was a collection of systematic reviews that set out to assess the "global burden" of lower back pain. The reviews were part of the Global Burden of Disease Study 2010, research that assessed the degree of ill health and disability in 187 countries, divided into 21 regions, for the years 1990, 2005 and 2010.
The authors point out that lower back pain is an extremely common health problem, and the leading cause of disability and work absence throughout much of the world.
Their paper describes in detail the methods and results for estimating the global burden of lower back pain in the 2010 study.
What did the research involve?
The researchers defined lower back pain as pain "from the lower margin of the twelfth ribs to the lower gluteal folds", with or without pain referred down one or both legs, that lasts for at least one day.
They classified the condition into four categories, depending on the level of severity, whether the pain was chronic (long term) or acute, and whether it involved referred pain in the leg. Each category was given a weighting for the degree of disability caused.
They then undertook systematic reviews of the:
- prevalence – how many people are affected by lower back pain overall
- incidence – how many people are diagnosed with lower back pain in a specific time period
- remission – data on if and when the lower back pain went away
- duration – how long it lasted
- risk of death associated with the condition
The researchers found no relevant studies on duration and remission, and no evidence that lower back pain is associated with a higher risk of death.
They identified 170 studies on prevalence, of which 117 met the criteria to be included in the systematic review, with data available from 47 countries and 16 of the 21 world regions. Prevalence was broken down by age, sex and region.
They also looked at surveys from five countries about the impact of acute and severe chronic lower back pain, with and without leg pain. They also considered additional information on the condition from national health surveys carried out in more than 50 countries, although this data was not included in the systematic reviews.
The researchers used the disability weighting, together with the data on prevalence, to calculate the overall level of disability caused by lower back pain for the years 1990, 2005 and 2010. The measure they used to express this is called years lived with disability (YLDs).
The authors also assessed the toll taken by lower back pain using a measure called disability adjusted life years (DALYs). These are worked out by combining the number of years of life lost as a result of early death (YLL) and the number of years lived with disability (YLD). As there is no risk of mortality from lower back pain, in this study YLDs and DALY estimates are the same.
What were the basic results?
Researchers found that out of all 291 conditions studied in the Global Burden of Disease 2010 Study, lower back pain ranked highest in terms of disability (YLDs) than any other condition.
It ranked sixth in terms of the overall burden, measured as DALYs. The number of DALYs increased from 58.2 million (95% confidence interval [CI] 39.9 million to 78.1 million) in 1990, to 83 million (95% CI 56.6 million to 111.9 million) in 2010.
Globally, almost 1 in 10 (9.4%) people had lower back pain (95% CI 9.0 to 9.8), with slightly more men (10.1%) suffering the condition than women (8.7%). Both prevalence and burden increased with age. Prevalence was highest in Western Europe, with 15% suffering back pain.
How did the researchers interpret the results?
The researchers say that lower back pain causes more global disability than any other condition. With the ageing world population, this burden can be expected to increase.
There is an urgent need for further research to better understand the condition and attempt to mitigate its growing burden.
This systematic review used a disability rating to quantify the severity of lower back pain in combination with data on prevalence throughout the world.
As the authors point out, this study had some limitations, however. Some of the information it used came from questionnaires asking people to recall their back pain, which could make the results prone to bias.
Also, the categories of disability used referred to the effect of back pain on bodily functions such as washing and dressing, rather than broader aspects of life, such as wellbeing or economic impact. This means it cannot estimate the full impact of back pain in a population.
However, with this in mind, it could be the case that the study actually underestimates, rather than overestimates, the burden of lower back pain.
Back pain is not usually linked to any life-threatening conditions, but its effect can be debilitating and distressing.
It's a cliché that doctors know nothing about the back, but, as with most clichés, it has a kernel of truth: lower back pain is a poorly understood condition. Further research is urgently needed into the ways in which back pain can better be prevented and managed.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.