Association between subjective sleepiness and severity of sleep-disordered breathing among truck drivers in Japan.

Introduction: The purpose of this study is to investigate the association of subjective sleepiness and severity of sleep-disordered breathing among truck drivers in Japan. Materials and methods: Age adjusted subjective daytime sleepiness was not significantly related to the severity of sleep-disordered breathing in this population (p =0.36). Among the subjects who had severe sleep-disordered breathing (RDI⩾20), ESS score of non-sleepiness and moderate sleepiness was 56.3% and 34.4% respectively. For the BMI stratified analysis, prevalence of non-sleepiness and moderate sleepiness for severe sleep-disordered breathing was 60.0% and 30.0% for <25kg/m2, and 54.6% and 36.4% for ⩾25kg/m2. Results: Age adjusted subjective daytime sleepiness was not significantly related to the severity of sleep-disordered breathing in this population (p =0.36). Among the subjects who had severe sleep-disordered breathing (RDI⩾20), ESS score of non-sleepiness and moderate sleepiness was 56.3% and 34.4% respectively. For the BMI stratified analysis, prevalence of non-sleepiness and moderate sleepiness for severe sleep-disordered breathing was 60.0% and 30.0% for <25kg/m2, and 54.6% and 36.4% for ⩾25kg/m2. Conclusion: The results of our study showed that more than 90% of the participants who had severe sleep-disordered breathing did not have severe daytime sleepiness. Objective screening for sleep-disordered breathing is_ important even if the drivers have no subjective sleepiness. Acknowledgements: We are indebted to Mr. Shuzo Fujioka, the president of Nara Trucking Association for great effort. This study was supported in part by grants from the International Association of Traffic and Safety Sciences Grant No. H2422, from the Japanese Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for research B: 22390134 in 2010–2012, Grant-in-Aid for research C: 23590796 in 2011–2013), and from the Japanese Society for the Promotion of Science, and by Health and Labour Sciences Research Grants from the Ministry of Health, Welfare and Labour, Japan. (Comprehensive Research on Life- Style Related Diseases including Cardiovascular Diseases and Diabetes Mellitus 201021038A in 2010–2012). [Copyright &y& Elsevier]