Background: Organisational-level workplace interventions are thought to produce more sustainable effects on the health of employees than interventions targeting individual behaviours. However, scientific evidence from intervention studies does not fully support this notion. It is therefore important to explore conditions of positive health effects by systematically reviewing available studies. We set out to evaluate the effectiveness of 39 health-related intervention studies targeting a variety of working conditions.
Methods: Systematic review. Organisational-level workplace interventions aiming at improving employees' health were identified in electronic databases and manual searches. The appraisal of studies was adapted from the Cochrane Back Review Group guidelines. To improve comparability of the widely varying studies we classified the interventions according to the main approaches towards modifying working conditions. Based on this classification we applied a logistic regression model to estimate significant intervention effects.
Results: 39 intervention studies published between 1993 and 2012 were included. In terms of methodology the majority of interventions were of medium quality, and four studies only had a high level of evidence. About half of the studies (19) reported significant effects. There was a marginally significant probability of reporting effects among interventions targeting several organisational-level modifications simultaneously (Odds ratio (OR) 2.71; 95% CI 0.94-11.12), compared to those targeting one dimension only.
Conclusions: Despite the heterogeneity of the 39 organisational-level workplace interventions underlying this review, we were able to compare their effects by applying broad classification categories. Success rates were higher among more comprehensive interventions tackling material, organisational and work-time related conditions simultaneously. To increase the number of successful organisational-level interventions in the future, commonly reported obstacles against the implementation process should be addressed in developing these studies.