Combined musculoskeletal pain in the upper and lower body: associations with occupational mechanical and psychosocial exposures

Purpose: Pain in more than one site is common in working populations. We aimed to characterise combined pain (pain in the upper and lower body) and to evaluate whether the prevalence of combined pain is positively related to combined occupational mechanical exposures to the upper and lower body and to high psychosocial job strain. Methods: This cross-sectional study was based on questionnaire data from the Musculoskeletal Research Database at the Danish Ramazzini Centre. The study included 14,081 men and 20,173 women. Occupational exposures were assessed by job exposure matrices. We analysed the prevalence of pain limited to the upper body, pain limited to the lower body, and combined pain in relation to occupational exposures using Poisson regression. Results: During the last year, 23.2 % of the men and 33.9 % of the women reported combined pain, which was characterised by somatisation, illness worrying, and low SF-36 scores. For men, the adjusted prevalence ratio for combined pain was 1.51 [95 % confidence interval (95 % CI) 1.40–1.64] in relation to exposures limited to the upper body and 2.24 (95 % CI 2.11–2.39) in relation to combined exposures. For women, the corresponding adjusted prevalence ratios were 1.56 (95 % CI 1.50–1.63) and 1.55 (95 % CI 1.50–1.61). High job strain was related to pain among men, only. Conclusion: Combined pain may in part be explained by local effects of occupational mechanical exposures acting at more than one site.