Sleep disordered breathing (SDB) is defined by episodes of apneas and hypopneas during sleep and this condition is widely prevalent to potential in the general population. The prevalence of SDB (apnea-hypopnea index (AHI)≥15) among United States was 13% of men and 6% of women, and 27.1 % of men and 11.1 % of women among Japan. Several studies have concluded that SDB is a risk factor for motor vehicle crashes (MVCs), and a meta-analysis demonstrated that patients with SDB have a crash risk about 2.5 times that of individuals without SDB. Moreover, the treatment by continuous positive airway pressure therapy could reduce the risk of MVCs. Thus, early detection, treatment and prevention of SDB carries safety on driving significance. Also, subjective excessive daytime sleepiness (EDS) is widely known as a risk factor for MVCs, and it is included in one of the diagnostic criteria of sleep apnea syndrome (SAS). However, a previous study reported that there is no significant difference in AHI score between the SDB patients with and without EDS. Other study also suggested that there are comparatively many SDB patients who do not feel subjective EDS. The cause of this discrepancy is that assessment of subject EDS might be underestimated by chronic sleep deprivation and differs in each individual. While ample studies have conducted the association between SDB and MVC, only a prospective cohort study presumed the association of SDB with or without subjective EDS on the risk of MVC. Therefore, we conducted a prospective cohort study among 1,047 Japanese community residents to examine whether individuals with SDB were at increased risk of MVCs, independent of subjective EDS. The participants in this study completed a general sleep questionnaire and screening of SDB. SDB was assessed by a single-channel portable monitor; “Somnie” (NGK Spark Plug Co., Nagoya, Japan) which measured the respiratory disturbance index (RDI) during one-night sleep at home. Participants were classified into the SDB group (RDI ≥10) and non-SDB group (RDI <10). Subjective EDS was defined by Japanese version of Epworth Sleepiness Scale (JESS) scores ≥11. A follow-up questionnaire five years after the baseline ascertained history of MVC over the period. Sex-specific multivariable logistic regression analysis examined the association between SDB and MVC after stratification by subjective EDS. The multivariable-adjusted odds ratios (95% confidence interval) for MVC among the female SDB group were 1.66 (1.05-2.63) compared with the non-SDB group (Figure-1), and this association was more evident in females without subjective EDS, but not among those with subjective EDS (Figure-1). There was no significant association in males. The major finding of the present study is to demonstrate the significant association between SDB and risk of MVC in female participants, and this association was more evident among those without subjective EDS, suggesting that SDB is a risk factor for MVC, irrespective of subjective EDS, and therefore, screening for SDB even among individuals without subjective EDS might be significant for prevention of MVC among community dwelling population. More details are described in our article: Matsuo R, et al: Sleep disordered breathing and subjective excessive daytime sleepiness in relation to the risk of motor vehicle crash: the Toon Health Study. Sci Rep, 2020; 10 (1): 17050. doi: 10.1038/s41598-020-74132-7.