Dose-response associations between musculoskeletal disorders and physical and psychosocial factors among construction workers.

BACKGROUND: As musculoskeletal disorders are common in general populations and they therefore constitute a heavy burden to society, the identification of their determinants is important. The aim of this study was to identify dose-response associations for location-specific prevalences of musculoskeletal disorders with various physical exposures and psychosocial factors in a large group of workers.
METHODS: The study was based on cross-sectional data from self-administered questionnaires filled out by 85 191 male employees in the Swedish construction industry. In addition to symptoms from nine musculoskeletal locations, the questionnaire addresses physical exposures and psychosocial factors. Logistic regression methods were used to study disorder prevalence in relation to scales of these exposures and factors.
RESULTS: Compared with working rarely in a stooping or twisted posture, the odds ratio (OR) for lower back disorder with respect to often working in this posture was 3.05 [95% confidence interval (95% CI) 2.73-3.42]. The OR values for work with hands above the shoulders and for neck and shoulder disorders were 2.93 (95% CI 2.65-3.24) and 3.66 (95% CI 3.32-4.04), respectively. Among the psychosocial factors, sleeping problems and hurrying without reason were associated with symptoms in all of the body locations, the highest OR being found for neck symptoms and sleeping problems, 2.44 (95% CI 2.15-2.78).
CONCLUSIONS: Work in awkward postures has strong location-specific dose-response associations. In contrast, some psychosocial factors, primarily those reflecting characteristics of individual persons, are strongly associated with symptoms in all body locations. Symptoms seem not to be associated with factors like support from workmates or supervisors or control of the work situation. All location-specific prevalence rates seem to increase strongly with age.