Psychosocial work stress, leisure time physical exercise and the risk of chronic pain in the neck/shoulders: Longitudinal data from the Norwegian HUNT Study.

OBJECTIVES

To prospectively investigate if the risk of chronic neck/shoulder pain is associated with work stress and job control, and to assess if physical exercise modifies these associations.

MATERIAL AND METHODS

The study population comprised 29 496 vocationally active women and men in the Norwegian Nord-Trøndelag Health Study (HUNT Study) without chronic pain at baseline in 1984-1986. Chronic neck/shoulder pain was assessed during a follow-up in 1995-1997. A generalized linear model (Poisson regression) was used to calculate adjusted relative risks (RRs).

RESULTS

Work stress was dosedependently associated with the risk of neck/shoulder pain (ptrend < 0.001 in both sexes). The women and men who perceived their work as stressful "almost all the time" had multi-adjusted RRs = 1.27 (95% confidence interval (CI): 1.1-1.47) and 1.71 (95% CI: 1.46-2), respectively, referencing those with no stressful work. Work stress interacted with sex (p < 0.001). Poor job control was not associated with the risk of neck/shoulder pain among the women (RR = 1.04, 95% CI: 0.92-1.19) nor the men (RR = 1.09, 95% CI: 0.95-1.26). Combined analyses showed an inverse dose-dependent association between hours of physical exercise/week and the risk of neck/shoulder pain in the men with no stressful work (ptrend = 0.05) and among the men who perceived their work as "rarely stressful" (ptrend < 0.02). This effect was not statistically significant among the women or among men with more frequent exposure to work stress.

CONCLUSIONS

Work stress is an independent predictor of chronic neck/shoulder pain and the effect is stronger in men than in women. Physical exercise does not substantially reduce the risk among the persons with frequent exposure to work stress.