Association of long working hours and multi-site work-related musculoskeletal disorders among transportation industry workers in Beijing, China.

Background: Long working hours can lead to a variety of diseases, while the relationship between long work hours and multi-site work-related musculoskeletal disorders (WMSDs) remains unclear. This study aims to explore the association between working hours and multi-site WMSDs.

Methods: A cross-sectional study was conducted among 2636 transportation industry workers. The Nordic Musculoskeletal Questionnaire was used to assess musculoskeletal disorders. Workers were grouped by weekly working hours (≤ 40 h/wk, 40-55 h/wk, and ≥ 55 h/wk) to compare the prevalence of WMSDs. The correlation between different WMSDs sites and the influencing factors of multi-site WMSDs were analyzed by log-binomial model and logistic regression model.

Results: 897 (34.0%) participants faced long working hours. 995 (37.7%) participants suffered from WMSDs, while the highest prevalence of WMSDs symptoms occurred in neck (25.4%), followed by low back (18.4%) and shoulders (14.5%). Wrists WMSDs were associated with WMSDs in necks, shoulders, elbows, hips, and ankles (OR = 2.07-8.01). According to binary and multivariate logistic regression, the risk of WMSDs was higher in participants who worked 40-55 h/wk (OR: 1.30, 95% CI: 1.09-1.56) and more than 55 h/wk (OR: 2.15, 95% CI: 1.46-3.16) compared to participants who worked less than 40 h/wk. Additionally, participants who worked 40-55 h/wk (OR: 1.39, 95% CI: 1.09-1.78) and more than 55 h/wk (OR: 2.92, 95% CI: 1.82-4.70) were more likely to suffer from WMSDs in three or more sites.

Conclusion: Long working hours were positively associated with multi-site WMSDs. Early preventive and management measures of long working hours and WMSDs are of importance.