Psychological and mechanical workload and musculoskeletal symptoms among female child-care workers

The aim was to test a structural model of the relations between psychological and mechanical workload and musculoskeletal neck/shoulder symptoms. This two-wave longitudinal cohort study was based on a questionnaire survey among Swedish female child-care workers (n=789). Two models were tested using structural equation modelling, one containing only those participants considered symptom free at baseline, thus focusing on symptom development, and one containing all participants irrespective of their baseline musculoskeletal status. The results indicate that psychological workload was related to the development of neck/shoulder symptoms, and thus highlight the importance of addressing psychosocial work environment factors in organization design and workplace interventions. However, psychological workload was not related to symptoms (when controlling for baseline mechanical workload and symptoms) in the model not distinguishing between different symptoms processes. These findings point to the importance of distinguishing between different processes such as development, maintenance and recovery from symptoms in studies of workplace factors and musculoskeletal symptoms. Mechanical workload was not related to neck/shoulder symptoms, when controlling for baseline psychological workload and symptoms, in any of the models tested. No interaction effect was found for psychological and mechanical workload on neck/shoulder symptoms.