Risk factors for more severe regional musculoskeletal symptoms: a two-year prospective study of a general working population.

OBJECTIVE: To quantify the relative contribution of work-related physical and psychosocial factors, individual factors, and health-related factors to the development of more severe musculoskeletal pain in the neck and upper limbs and the back and lower limbs.
METHODS: In this cohort study of 5,604 workers from industrial and service companies, we collected information on work-related physical and psychosocial exposures and on individual and health-related factors. Questionnaires were completed at baseline by 4,006 participants (71.5%) and after 24 months by 3,276 (82%). At followup, participants with no or minor pain were included in Cox regression analyses to determine which factors predicted more severe regional pain.
RESULTS: Of the 4,006 baseline respondents, only 7.7% were free of regional pain. A total of 1,513 participants were free of severe pain at baseline and completed the 24-month followup. Highly repetitive work predicted arm pain, heavy lifting and prolonged standing predicted low back pain, and heavy pushing or pulling predicted lower limb pain. Low job satisfaction predicted neck/shoulder pain and lower limb pain, whereas other psychosocial work place factors were only of marginal importance. High levels of fear avoidance were associated with arm pain and lower limb pain. A high body mass index was highly associated with lower limb pain.
CONCLUSION: Very few workers are totally free of pain in musculoskeletal regions, and we question the concept of incidence of musculoskeletal pain. The transition from no or minor pain to more severe pain was influenced by physical and psychosocial work place factors together with individual and health-related factors.