Sleeping problems as a risk factor for subsequent musculoskeletal pain and the role of job strain: results from a one-year follow-up of the Malmö Shoulder Neck Study Cohort.

BACKGROUND: The role of sleeping problems in the causal pathway between job strain and musculoskeletal pain is not clear. Purpose: To investigate the impact of sleeping problems and job strain on the one-year risk for neck, shoulder, and lumbar pain. METHOD: A prospective study, using self-administered questionnaires, of a healthy cohort of 4,140 vocationally active persons ages 45-64, residing in the city of Malmo. RESULTS: At follow-up, 11.8% of the men and 14.8% of the women had developed pain. The odds ratios (OR) for pain at follow-up and sleeping problems at baseline were 1.72 (95% CI: 1.13-2.61) in men and 1.91 (1.35-2.70) in women. Regarding exposure to job strain, ORs were 1.39 (0.94-2.05) for men and 1.63 (1.18-2.23) for women. These statistically significant risks remained so when controlled for possible confounding. A modest synergistic effect was noted in women with concurrent sleeping problems and job strain, but not in men. CONCLUSION: One in 15-20 of all new cases of chronic pain in the population could be attributed to sleeping problems. No evidence was found for a causal chain with job strain leading to musculoskeletal pain by the pathway of sleeping problems.