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Introduction Associations of sleep duration with health outcomes could differ depending on whether sleep is restorative. Age-related changes in the relationship between sleep need and sleep opportunity could also influence these associations. Methods Using data from 5804 participants of the Sleep Heart Health Study, a multicenter population-based prospective cohort study, we examined the longitudinal association of feeling rested after sleep combined with in-home polysomnographymeasured total sleep time (TST) or time in bed (TIB) with allcause mortality. Results A total of 223 (7.1%) and 991 (37.0%) deaths were reported in 3128 middle-aged (40–64 years) and 2676 older adults (≥ 65 years) with a mean (standard deviation) age of 54.5 (6.6) and 73.3 (5.7) years at baseline over a median (interquartile range) follow-up time of 12.3 (11.3–13.5) and 11.3 (8.2–12.2) years, respectively. Among middleaged adults, compared with the interquartile TST range (331 to < 414 min) with feeling rested, the lowest TST quartile (< 331 min) with feeling unrested was associated with higher mortality (adjusted hazard ratio [aHR], 1.54; 95% confidence interval [CI] 1.01–2.33); the highest TST quartile (≥ 414 min) with feeling rested was associated with lower mortality, independently from health and sleep covariates (aHR, 0.55; 95% CI 0.32–0.97). Among older adults, TIB, but not TST, was consistently associated with mortality. Compared with the interquartile TIB range (404 to < 482 min) with feeling rested, the highest TIB quartile (≥ 482 min) with feeling unrested was associated with higher mortality (aHR, 1.57; 95% CI 1.23–2.01). Conclusion The results suggest the role of restorative sleep in differentiating the effects of sleep duration on mortality outcomes for middle-aged and older adults. Our findings further suggest that there is a need to change the way to optimize sleep hygiene according to age groups: in middle-aged adults maintaining a substantial amount of sleep is more critical, whereas in older adults optimizing sleep opportunity is more critical to determine the sleep–mortality relationship. Support (if any) This work was supported by the Ministry of Health, Labor and Welfare, Government of Japan (Grant numbers #19FA1009 and #21FA1002).

Introduction Polysomnography (PSG) has been suggested to be useful as an objective indicator (biomarker) that contributes to the diagnosis and severity evaluation of various sleep disorders. However, its regular use is still limited to the specialized institutions for sleep disorders. Therefore, PSG is essential for clinical diagnosis of only some sleep disorders, and further application of PSG in conjunction with biomarker development of disorders including such as insomnia, and psychiatric disorders with comorbid sleep disorders is expected. The aim of this project is to establish a PSG databank for sleep disorders in collaboration with major PSG laboratories in Japan. Methods This project is collaborated with medical and research institutions that conduct PSG on a large scale in Japan. The National Center of Neurology and Psychiatry (NCNP) serves as the core institution. The initial collaborating institution is the Tokyo Medical University, which is in cooperation with the Yoyogi Sleep Disorder Center, the largest PSG facility in the Kanto region. We also collaborate with three other core PSG facilities in the Kanto, Tohoku and Kyushu regions: the Nihon University, the Akita University (in cooperation with the Akita Sleep Clinic), and the Kurume University. This project has been approved by the Ethics Committee of the NCNP. Results We have stored about 3,000 PSG data evaluated by the standard of the American Academy of Sleep Medicine clinical practice guideline or the traditional Rechtschaffen & Kales standard with adjunct clinical metadata for the past 9 years at the NCNP, about 17,900 at the Tokyo Medical University, about 1,900 at the Nihon University, about 500 at the Akita University, and about 3,000 at the Kurume University. We are continuously collecting and banking data for enhancing research availability of the PSG databank for sleep disorders. Conclusion The collected data will be used for research on the development of objective indices for sleep disorders or neuropsychiatric disorders, for which objective indices are lacking in diagnosis and pathological evaluation. Support (if any) This work was supported by the Intramural Research Grant (#2-1) for Neurological and Psychiatric Disorders of NCNP.

Introduction There is evidence for a mismatch between subjective and objective sleep durations not only in individuals with insomnia but also in healthy individuals . However, it is unclear how such discrepancy impacts long-term health outcomes. This study investigated whether and how the discrepancy between subjective and objective sleep duration affected all-cause mortality in a sample of community-dwelling older adult men, aged ≥ 65 years. Methods We conducted a secondary analysis of data obtained via the Osteoporotic Fractures in Men Sleep Study, a community-based, longitudinal, observational, and multicenter study. We included data from 2,674 individuals who underwent an in-home polysomnography, completed morning surveys to assess subjective sleep duration during the polysomnography, and for whom survival or death data were available. We assessed the longitudinal association between misperception index (MI), calculated as MI = (objective sleep duration – subjective sleep duration) / objective sleep duration, and all-cause mortality. MI was treated as both a continuous and categorical predictor: the lowest (≤ -0.19; the overestimation of sleep duration) and highest MI quartiles (> 0.08; the underestimation of sleep duration) were compared to the interquartile range of MI (-0.19 Results During the follow-up with a mean (standard deviation) of 10.8 (4.2) years, 1,596 deaths (59.7%) were observed. As a continuous variable, MI showed a negative association with all-cause mortality after adjusting for multiple covariates, including polysomnography-measured objective sleep duration (fully adjusted hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.56–0.84). As a categorical variable, the lowest MI quartile (vs. the interquartile MI range) was associated with increased mortality (fully adjusted HR, 1.28; 95% CI, 1.12–1.46), whereas the highest MI quartile was not associated with mortality (fully adjusted HR, 0.97; 95% CI, 0.85–1.11). Conclusion The subjective overestimation (“reverse” misperception) of sleep duration, may be a risk factor for all-cause mortality in older men. Further investigations are needed to examine physiological mechanisms through which subjective overestimation of sleep duration leads to negative long-term health outcomes. Support (if any) This work was supported by the Ministry of Health, Labor and Welfare, Government of Japan (Grant numbers #19FA1009 and #21FA1002).