The association of socioeconomic status and psychosocial and physical workplace factors with musculoskeletal injury in hospital workers

Background The combined effect of socioeconomic, organizational, psychosocial, and physical factors on work‐related musculoskeletal disorders (WRMSDs) were studied in a heterogeneous, socioeconomically diverse sample (cases and their matched referents) of hospital workers. Methods Cases were defined by a new acute or cumulative work‐related musculoskeletal injury; referents were matched by job group, shift length, or at random. Information was obtained through telephone interviews and on‐site ergonomics observation. Questionnaire items included sociodemographic variables, lost work time, work effectiveness, health status, pain/disability, and psychosocial working conditions using Effort Reward Imbalance (ERI) and Demand‐Control (DC) models. Two multivariate models were tested: Model 1 included occupation as a predictor; Model 2 included education–income as a predictor. Results Cases reported greater pain, disability, lost time, and decreased work effectiveness than the referents. Model 1 was statistically significant for neck/upper extremity injury (Chi‐square = 19.3, P = 0.01), back/lower extremity injury (Chi‐square = 14.0, P = 0.05), and all injuries combined (Chi‐square = 25.4, P = 0.001). “Other Clinical” occupations (34% mental health workers) had the highest risk of injury (OR 4.5: 95%CI, 1.7–12.1) for all injuries. The ERI ratio was a significant predictor for neck and upper extremity (OR 1.5: 95%CI, 1.1–1.9) and all injuries (OR 1.3; 95%CI, 1.04–1.5), per SD change in score. Conclusions In this study, the risk of WRMSDs was more strongly influenced by specific psychosocial and physical job‐related exposures than by broad socioeconomic factors such as education and income. Am. J. Ind. Med. 2007. © 2007 Wiley‐Liss, Inc.