Prolonged standing & demanding jobs impact low-back health

Source: Workplace OHS
Strategies to address the occurrence of low-back pain in workers may benefit from focusing on a combination of work-related psychosocial and mechanical risk factors, according to a new research paper.

In order to identify the work-related psychosocial and mechanical factors that contribute to the risk of moderate to severe low-back pain (LBP), researchers from the National Institute of Occupational Health in Oslo, Norway, collected data from a national study of living standards and the work environment, involving a randomly drawn cohort of 6745 adults (18 to 66 years) in paid employment or temporarily absent from such work.

Their paper has been published by Occupational &Environmental Medicine (OEM). An abstract is available for free on the OEM website.

Although more than one hundred risk factors for LBP have been identified previously, with a combination of work-related as well as non-work-related factors likely to contribute to the development of LBP in the majority of cases, the researchers said the overall evidence of occupational risk factors for LBP has been limited.

Findings and recommendation
Nevertheless, they said their study provides evidence of a substantial relationship between work-related mechanical and psychosocial factors and the development of LBP, which is estimated to account for 11-13.5 per cent of all sick days in the working population and is one of the largest single causes of absenteeism in western countries. It was noted that the risk of LBP associated with psychosocial exposure was not influenced by adjustment for mechanical risk factors and vice versa, indicating that psychosocial and mechanical factors are independent risk factors.

The most consistent and important psychosocial risk factor/predictor of LBP was identified as highly demanding jobs, with the following explanation offered by the researchers: 'high job demands may increase strain and subsequently, increase muscle tension or other physiological reactions that put individuals at a greater risk for developing LBP'.

The most consistent and important mechanical risk factor for LBP was identified as prolonged standing. Awkward lifting was also a consistent mechanical risk factor, which supported an association between LBP and nursing tasks (eg manually transferring patients), and the researchers noted the following:
'The effect of being exposed "a quarter of the working day or more" was similar to that of being exposed "three-quarters of the working day or more", indicating that even brief exposure to awkward lifting may influence LBP.'
Other work-related factors for LBP were squatting or kneeling and low job control, with the following explanation offered for the latter: 'employees with higher job control may have more autonomy and thus take more breaks, providing relief to their muscles and reducing the risk of LBP'.

The researchers found that low level of supportive leadership and working in a forward-bending position were not significant risk factors for LBP, and there were mixed findings regarding the impact of whole body vibration on LBP. They noted that monotonous work and role conflict have been identified as significant risk factors in previous studies.

Based on their findings, the researchers concluded that interventions aimed at reducing the development or return of LBP in the general working population may benefit from focusing on a range of work-related mechanical and psychosocial factors especially highly demanding jobs and physically demanding jobs involving prolonged standing, awkward lifting and squatting/kneeling.