Job decision latitude as a potential modifier of the contribution of physical workload to poor functioning in middle-aged employees.

OBJECTIVES: It was hypothesised that job decision latitude may alleviate the detrimental health effect of physical workload. The objective was to test whether job decision latitude modifies the effect of physically demanding work on poor physical functioning, and whether the effects of physically demanding work and job decision latitude are dependent on occupational social class.
METHODS: Data were derived from the Helsinki Health Study baseline questionnaire survey. The participants were employees of the City of Helsinki, Finland, aged 40-60 years. Functioning was measured by Short Form 36 physical component summary. Logistic regression models were used to analyse the data.
RESULTS: The hypothesised modification of the effect of physical demands at work on physical functioning by job decision latitude could not be demonstrated. The expected interaction effect was observed only for the semi-professional class, and interaction of physical demands, decision latitude and occupational social class was not statistically significant. Furthermore, the effects of physically demanding work as well as low decision latitude were of similar magnitude in all the occupational social classes.
CONCLUSIONS: The results suggest that for the majority of employees the effect of physical workload on physical functioning is independent of job decision latitude or occupational social class in general. Control over work conditions is unlikely to reduce difficulties to cope with physical demands, when the actual physical tasks are not changed.