Low back pain disability linked to workplace factors accounts for a third of all work related disability around the globe, indicates research published online in the Annals of the Rheumatic Diseases.
Agricultural sector workers and those aged between 35 and 65 seem to be at greatest risk, the findings show.
The researchers drew on data from the Global Burden of Disease 2010 study, which assesses ill health/disability arising from all conditions in 187 countries - grouped into 21 regions - for 1990, 2005, and 2010.
Disability arising from work was measured as disability adjusted life years (DALYs), calculated from a combination of years of life lost due to premature death and years of life lived with disability.
Relevant factors deemed to be linked to low back pain were jobs involving lifting, forceful movement, awkward positions and vibration. And estimates of the proportion of the working population employed in these jobs in 1990 and 2010 were based on data from the International Labour Organization Labour Force.
The calculations showed that in 2010 there were just short of 22 million DALYs worldwide caused by workplace related low back pain - amounting to more than a third of all DALYs linked to occupational risk factors.
Some 13.5 million DALYs were in men and 8.3 million in women, with those aged between 35 and 65 most at risk. The largest number of DALYs were in regions with the highest populations - Asia and North Africa and the Middle East.
And the highest rate of DALYs was in Asia, Oceania, and parts of Africa - places where employment in agriculture is more common.
Agricultural sector workers were almost four times as likely to develop low back pain disability as any other group of workers.
The absolute burden rose significantly between 1990 and 2010 in line with population increases and an ageing population, but fell by around 14% when calculated on an individual per capita basis as employment in high risk occupations has fallen.
[The global burden of occupationally related low back pain: estimates from the Global Burden of Disease 2010 study Online First doi 10.1136/annrheumdis-2013-204631]