Work-related mechanical risk factors for long-term sick leave: a prospective study of the general working population in Norway

Abstract

Background: The overall evidence for work-related mechanical exposures as risk factors for long-term sick leave (LTSL) in the general working population is limited.

Methods: The study cohort was randomly drawn from the general population in Norway, aged 18-69 years (n = 12 255, response at baseline = 60.9%). Eligible respondents were interviewed in 2009 and were registered with an active employee relationship of at least 100 actual working days in 2009 and 2010 (n = 6758). The outcome of interest was medically confirmed LTSL ≥40 working days during 2010.

Results: In total, 9.4% (635 individuals) were classified with LTSL during 2010. The risk of LTSL was higher in women, employees with fewer years of education, regular smokers, employees with chronic health complaints and employees with LTSL during 2009. After adjusting for these factors, we estimated that 24.6% of LTSL cases were attributable to work-related mechanical exposure. Mechanical risk factors were neck flexion, hand/arm repetition, standing, working with upper body bent forward and awkward lifting. The odds ratio for highest exposure levels ranged from 1.32 (95% confidence interval 1.04-1.69) for standing to 2.15 (95% confidence interval 1.24-3.73) for awkward lifting. A test for trend was statistically significant for all contributing factors (P ≤ 0.05), except standing. No psychosocial factors acted as major confounders related to any of the mechanical risk factors.

Conclusion: This study underlines the importance of work-related mechanical exposures as risk factors for LTSL in the general working population. An exposure-response relationship was indicated for 5 of the 10 factors evaluated.