Could work-related muscle activity explain sex differences in neck pain? A meta-analysis of a pooled dataset.

OBJECTIVES

Sustained activity of the upper trapezius muscle during work has been linked to the development of neck pain. Women have higher occurrences of neck pain than men, even in the same occupations. This study aimed to investigate sex-specific associations between upper trapezius muscle activity time-related variables and neck pain using a meta-analysis of pooled data.

METHODS

Seven Scandinavian research institutes provided surface electromyographic (EMG) data on the upper trapezius muscle activity during work and related questionnaire-based data on neck pain severity. EMG and questionnaire data were harmonized and pooled. Associations between upper trapezius muscle activity variables [median muscle activity, frequency of muscular rest periods, and periods with sustained muscle activity (SUMA)] and neck pain severity were investigated separately for women (N=293) and men (N=418) using linear regression analyses.

RESULTS

In the cross-sectional analyses, women showed significant positive associations between the number of short SUMA periods and negative associations for long SUMA periods in regard to neck pain severity. In the longitudinal analyses, women showed no significant associations. In the cross-sectional analysis for men, one significant positive association was found between median upper trapezius muscle activity and neck pain severity.

CONCLUSIONS

Compared to men, neck pain severity among women appears to be more dependent on upper trapezius muscle activity patterns at work. Therefore, ergonomic and organizational recommendations for work should be sex-specific or adjusted for women to reduce their prevalence of neck pain. Further research is needed to elucidate the underlying mechanisms of these sex differences.