Job strain and neck-shoulder symptoms: a prevalence study of women and men white-collar workers.

BACKGROUND Neck-shoulder symptoms are frequent among workers. Psychosocial factors at work have been associated with neck-shoulder symptoms, but few studies have examined job strain, the combined effect of high psychological demands (PD) and low decision latitude (DL). AIMS To examine the association between psychosocial factors at work and the prevalence of self-reported neck-shoulder symptoms among white-collar workers. METHODS In a cross-sectional study of 1543 white-collar workers, PD and DL at work were measured with Karasek's questionnaire. Prevalent cases were workers for whom neck-shoulder symptoms were present for >or=3 days during the previous 7 days and for whom pain intensity was greater than half the visual analogue scale. Gender and social support at work were evaluated as potential effect modifiers. RESULTS Workers exposed to high job strain had a higher prevalence of neck-shoulder symptoms [adjusted prevalence ratio (PR): 1.54, 95% confidence interval (CI): 1.00-2.37]. No modifying effect of gender was observed in this association. The effect of job strain was stronger in workers with low social support (adjusted PR: 1.84, 95% CI: 0.92-3.68). These associations tended to be stronger and/or more precise when using alternative exposures and case definition. Namely, a stronger job strain effect was observed when a tertile cut-off was used to classify exposure (adjusted PR: 2.47, 95% CI: 1.15-5.32). CONCLUSION These results suggest that primary prevention of neck-shoulder symptoms among white-collar workers should consider the exposure to job strain, especially when workers are exposed to low social support at work.