Date Presented 04/06/19
Shift workers commonly experience insufficient sleep due to working varied shifts. As such, they may experience sleepiness while driving, increasing their risk for crash-related injuries and fatalities. Yet, determinants for fitness to drive in shift workers with insufficient sleep have not been synthesized. This systematic literature review synthesizes and critically appraises peer-reviewed literature on fitness to drive and driving performance in shift workers with insufficient sleep.
Primary Author and Speaker: Melissa Knott
Contributing Authors: Sherrilene Classen, Sarah Krasniuk, Marisa Tippett, Liliana Alvarez
PURPOSE: Sleepiness while driving increases the risk of motor vehicle crashes via impairing physical or cognitive function, or through falling asleep at the wheel (Bioulac et al., 2017; Higgins et al, 2017). Over the past year, approximately 11% of drivers in the United States fell asleep at the wheel (Higgins et al, 2017), presenting a safety risk for road users. Factors, such as shift work and insufficient sleep, increase the risk of sleep-related crashes (Bioulac et al., 2017). Nevertheless, the literature has not yet established the determinants of sleepiness on fitness to drive of shift workers. Therefore, the purpose of this Systematic Literature Review (SLR) is threefold: 1) To classify the level of evidence for the risk and protective factors of fitness to drive and driving performance in shift workers experiencing insufficient sleep. 2) To determine the level of confidence in the evidence for each risk and protective factor. 3) Suggest evidence-based recommendations for clinical practice, research priority, and policy protocol.
DESIGN: To achieve the purpose, the research team (N=4) conducted a SLR following Cooper & Hedge’s (2009) methodology: 1) formulated the research question, 2) located and selected studies, 3) extracted data, 4) conducted a critical appraisal, 5) analyzed and presented data, 6) interpreted results, and are in the process of 7) disseminating information.
METHODS: A research librarian and graduate research student developed the search strategy to promote content saturation targeting six databases: CINAHL, EMBASE, ProQuest Nursing and Allied Health, PsycINFO, PubMed, and Scopus. The search strategy employed subject headings and keywords encompassing the constructs of interest, e.g., driving, shift work, insufficient sleep. Two pairs of reviewers (N=4) independently completed title and abstract screens for study inclusion: quantitative scientific on-road or driving simulator studies, in the English language, with adult participants, 16-65 years old, employed in shift work and experiencing insufficient sleep. Driving outcomes had to be determined through on-road or driving simulator assessments. Reviewers excluded studies with intervention, review, or qualitative study designs, and studies that did not include on-road or driving simulator assessment outcomes with shift worker participants. Included titles and abstracts underwent full-text review to verify study inclusion. Reviewers conducted footnote chasing to identify relevant studies for the SLR. Two reviewers will independently conduct data extraction and critical appraisal following the 2011 American Academy of Neurology (AAN) Guidelines.
RESULTS: Database searches and footnote chasing produced 1185 unique studies for review. After title and abstract screens, 21 studies met inclusion for full text review; of these, 2 on-road and 10 driving simulator studies met inclusion for the SLR. Overall, studies included 309 shift workers (63% male) and occurred in the United States (N=7), Sweden (N=3), Belgium (N=1), or China (N=1). Preliminary critical appraisal identified: 1) Weak (i.e., Class III) to insufficient (i.e., Class IV) levels of evidence, and 2) Possible (i.e., Level C) to insufficient conclusions (i.e., Level U) for protective or risk factors determining fitness to drive in shift-workers with insufficient sleep.
CONCLUSIONS: Insufficient sleep is associated with impaired physical and cognitive function, which may compromise the fitness to drive of shift-workers. Future research employing gold-standard on-road assessments in this population may provide additional high-quality data and lay groundwork for recommendations such as evidence-informed prevention strategies, or critical decision-making to mitigate adverse effects and improve road safety.
References
AAN (American Academy of Neurology). (2011). Clinical Practice Guideline Process Manual, 2011 Ed. St. Paul, MN: The American Academy of Neurology.
Bioulac, S., Micoulaud-Franchi, J.A., Arnaud, M., Sagaspe, P., Moore, N., Salvo, F., & Philip, P. (2017). Risk of motor vehicle accidents related to sleepiness at the wheel: A systematic review and meta-analysis. Sleep, 40(10), 1-10. doi:10.1093/sleep/zsx134
Cooper, H., & Hedges, L. V. (2009). Research synthesis as a scientific process. In H. Cooper, L. V. Hedges & J. C. Valentine (Eds.), The handbook of research synthesis and meta-analysis (Second Ed.). New York, NY: Russel Sage Foundation.
Higgins, J.S., Michael, J., Austin, R., Akerstedt, T., Van Dongen, H.P.A., Watson, N., Czeisler, C., Pack, A.I., & Rosekind, M.R. (2017). Asleep at the wheel – The road to addressing drowsy driving. Sleep, 40(2), 1-9. doi: 10.1093/sleep/zxs001
