Sleepiness and the risk of road accidents for professional drivers: A systematic review and meta-analysis of retrospective studies

This paper reports the results of a search and review of available evidence on the risk of road crashes associated with sleepiness for professional drivers. Summary of the effects were grouped according to different sleepiness-inducing factors. Meta-analysis suggested that modestly increased accident risks were associated with excessive daytime sleepiness (EDS), sleep apnea and acute sleepiness, but not significantly associated with insomnia. Compared with non-professional drivers, sleep apnea had a smaller effect size and excessive daytime sleepiness had a similar effect size on professional drivers. Effects of other sleepiness inducing factors such as sleep debt, sleep quality and snoring were also presented without meta-analysis. Conducting this review revealed that the main problems in this research field were the limited number of studies available, poor control for confounding factors, failure to take severity levels into account and incomplete reporting.