Lack of REM Sleep as a Predictor of Mortality
Marie Benz, M.D., FAAD
July 7, 2020 (MedicalResearch.com) – MedicalResearch.com interview with:
Eileen B. Leary, Ph.D. Student, Epidemiology and Clinical Research, Stanford University
MedicalResearch.com: What is the background for this study? Would you briefly explain what is meant by REM sleep?
Response: Sleep is a regulated, reversible, and recurring loss of consciousness that is a critical requirement for a happy, healthy life. REM sleep is an important component of sleep defined by rapid eye movements and commonly associated with dreaming.
We learned from previous studies that sleep duration is associated with mortality, however little was known about how the different sleep stages relate to timing or cause of death.
MedicalResearch.com: What were the aims of this study?
Response: The goal of this study was to investigate the relationship between REM sleep and mortality and explore whether another sleep stage could be a better predictor of mortality. To evaluate generalizability of the findings, the final models were replicated in an independent cohort.
MedicalResearch.com: What are the main findings?
Response: We found a strong, consistent association between lower levels of REM sleep and increased rate of mortality. Middle-aged and older adults in the studies had a 13-17% higher mortality rate for every 5% reduction in REM sleep. This finding persisted for different causes of death (e.g. cardiovascular, cancer) and similar results were found when we analyzed an independent cohort. REM sleep was identified as the most important sleep stage for predicting all-cause mortality based on both conditional survival tree and random forest modeling.
MedicalResearch.com: What should readers take away from your report?
Response: REM sleep appears to be a reliable predictor of mortality and may have other predictive health values. Strategies to preserve REM may influence clinical therapies and reduce mortality risk, particularly for adults with <15% REM. However, more research is needed to better understand the relationship.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: Given the complex underlying biological functions, further studies are required to better understand the relationship between REM sleep and mortality. Accelerated brain aging may result in reduced REM sleep, making it a disease, frailty, or biologic aging marker rather than a direct mortality risk factor. Mechanistic studies are needed and strategies to preserve REM may influence clinical therapies and reduce mortality risk, particularly for adults with <15% REM.
MedicalResearch.com: Is there anything else you would like to add?
Response: This study used traditional statistics and machine learning to investigate the relationship between rapid eye movement (REM) sleep and mortality rate. The findings replicated in an independent cohort and persisted across multiple sensitivity analyses and mortality definitions. After submitting the publication, we successfully replicated the findings in a third cohort which significantly increases our confidence in the results.
Leary EB, Watson KT, Ancoli-Israel S, et al. Association of Rapid Eye Movement Sleep With Mortality in Middle-aged and Older Adults. JAMA Neurol. Published online July 06, 2020. doi:10.1001/jamaneurol.2020.2108