Do physical or psychosocial factors at work predict multi-site musculoskeletal pain? A 4-year follow-up study in an industrial population.

PURPOSE: Musculoskeletal pain at multiple sites is common among working-age people and greatly increases work disability risk. Little is known of the work-related physical and psychosocial factors contributing to multi-site pain.
METHODS: Survey responses from 734 employees (518 blue- and 216 white-collar; 65 % female) of a food processing company were collected twice, in 2005 and 2009. Information on musculoskeletal pain during the preceding week, and on environmental, biomechanical and psychosocial work exposures were obtained through a structured questionnaire. The association of multi-site pain with work exposures was estimated with logistic regression by gender and age group.
RESULTS: At baseline, 54 % of informants reported pain in more than one area, and 50 % at 4-year follow-up. Forty percent of all employees had multi-site pain both at baseline and at follow-up. Among those with multi-site pain at baseline, 69 % had multi-site pain at follow-up. Both repetitive work and awkward work postures at baseline were associated with multi-site pain at follow-up. Psychosocial factors (low job satisfaction, low team spirit, and little opportunity to exert influence at work) also strongly predicted multi-site pain at follow-up, especially among younger workers and men.
CONCLUSION: This prospective study provides new evidence of the high occurrence and persistence of musculoskeletal pain at multiple body sites in an industrial population with a strong association between biomechanical and psychosocial exposures at work and multi-site pain. Prevention of multi-site pain with many-sided modification of work exposures is likely to reduce work disability.