Job satisfaction and job security as moderators in the relationships among job demands, musculoskeletal symptoms, and work performance.

Purpose: This study examined whether job satisfaction and job security moderate the path from physical demands and job strain to impaired work performance via musculoskeletal symptoms in the upper extremities (MSUE). Moderation effects on five paths were examined: (1) from job strain to MSUE; (2) from job strain to work performance; (3) from physical demands to MSUE; (4) from physical demands to work performance; (5) from MSUE to work performance.

Methods: This was a cross-sectional study of 669 full-time workers from 9 manufacturing and 3 healthcare facilities. Data were collected via health interviews, on-site physical exposure assessments, and computation of the Strain Index by ergonomists, and self-administered questionnaires on psychosocial factors. Structural equation modeling and zero-inflated negative binomial regression analysis were performed to examine the moderation effect on each path.

Results: Job satisfaction moderated the relationship between MSUE and impaired work performance (B = - 0.09, 95% CI: - 0.15, - 0.04) and job security moderated the relationship between physical demands and MSUE (B = - 0.64, 95% CI: - 1.17, - 0.11). Interaction between job satisfaction and MSUE was significant on both the occurrence (OR: 0.92, 95% CI: 0.87, 0.97) and the degrees of impaired work performance (mean ratio: 0.99, 95% CI: 0.97, 0.99), while the interaction between job security and physical demands was significant only on the degrees of MSUE (mean ratio: 0.94, 95% CI: 0.89, 0.99).

Conclusion: Job satisfaction and job security can, respectively, mitigate the adverse impacts of working with MSUE and physical demands on work performance. Workplace interventions to improve workers' job satisfaction and job security can contribute to their musculoskeletal health and work performance.