Rotating shift work and the metabolic syndrome: a prospective study

Background Several studies have documented on the elevated cardiovascular risk among shift workers. In order to further explore this relation, we aimed at assessing the association between rotating shift work and the incidence of the metabolic syndrome (MetS). Methods In this population-based prospective study, 1529 employees from several large Belgian companies were followed for a median observation period of 6.6 years with respect to the onset of the MetS and its separate components. Results At baseline, 309 men (20.2%) were rotating shift workers. The MetS incidence rate in these shift workers (60.6 per 1000 person-years) was increased in comparison with day workers (37.2 per 1000 person-years) with an odds ratio (95% CI) of 1.77 (1.34-2.32). Multivariate adjustment for potential lifestyle and work-related confounders did only marginally affect the strength of the association. The risk for the development of MetS gradually increased independently with accumulated years of shift work. Rotating shift work not only had an impact on MetS as a cluster of conditions but on each of its individual components as well. Conclusions Hence, prospective evidence was found that rotating shift work increases the risk for developing the MetS over a period of 6 years.