Covariation between workplace physical and psychosocial stressors: evidence and implications for occupational health research and prevention

There is increasing interest in distinguishing the effects of physical and psychosocial workplace stressors on the aetiology of work-related musculosk eletal disorders (MSD). Modest associations have been found between psychos ocial stressors and MSD, such as intensive load, monotonous work and low jo b control. Interpretation of these results has been limited by likely covar iation between physical and psychosocial stressors. This investigation exam ined exposure covariation among blue- and white-collar workers employed in a mass production manufacturing environment (N = 410). Physical stressors w ere assessed from questionnaire and accelerometry. Psychosocial stressors w ere assessed from questionnaire. Pearson and Spearman correlation coefficie nts were computed. An exploratory factor analysis procedure identified poss ible common factors linking specific physical and psychosocial stressors. M oderate to high correlations between some physical and psychosocial stresso rs showed evidence of covariation both across and within groups. Covariatio n was strongest among blue- collar production and low-status office workers . Factor analysis results showed considerable shared variance between some physical and psychosocial stressors, such as repetition and job control, su ggesting that these disparate stressors manifest from common work organizat ion factors that govern the structure of work. While recognizing the concep tual differences between physical and psychosocial stressors, these results call attention to the strong empirical relationships that can exist betwee n some stressors in the workplace setting. To guard against ambiguous study findings that can occur when exposures are mixed, it is critical that futu re epidemiologic studies include information about the degree of associatio n between task-level stressors. Future research on work organization determ inants of task-level stressors, and their coincident occurrence in jobs wit h greater specialization, may provide promising new insights into the natur e of risk for MSD and effective prevention strategies.