Less REM sleep increases death risk: JAMA Neurology
USA: Middle-aged and older adults with less rapid eye movement (REM) sleep are more likely to die, suggests a recent study in the journal JAMA Neurology. According to the study, decreased percentage of REM sleep may increase the risk for all-cause, cardiovascular, and other non-cancer-related mortality.
REM sleep has been linked with health outcomes, but not much is known about the relationship between REM sleep and mortality. Eileen B. Leary, Stanford University, Palo Alto, California, and colleagues investigated whether REM sleep is associated with a greater mortality risk in 2 independent cohorts. Also, they explored whether another sleep stage could be driving the findings.
This study used data from the Outcomes of Sleep Disorders in Older Men (MrOS) Sleep Study and Wisconsin Sleep Cohort (WSC). MrOS participants were recruited from December 2003 to March 2005, and WSC began in 1988. MrOS and WSC participants who had REM sleep and mortality data were included. The analysis was conducted from May 2018 to December 2019.
The primary outcome was all-cause and cause-specific mortality confirmed with death certificates.
The MrOS cohort included 2675 individuals (2675 men [100%]; mean [SD] age, 76.3 [5.5] years), and was followed up for a median (interquartile range) of 12.1 (7.8-13.2) years. The WSC cohort included 1386 individuals (753 men [54.3%]; mean [SD] age, 51.5 [8.5] years), and was followed up for a median (interquartile range) of 20.8 (17.9-22.4) years.
Key findings of the study include:
- MrOS participants had a 13% higher mortality rate for every 5% reduction in REM sleep (percentage REM sleep SD = 6.6%) after adjusting for multiple demographic, sleep, and health covariates (age-adjusted hazard ratio, 1.12; fully adjusted hazard ratio, 1.13).
- Results were similar for cardiovascular and other causes of death. Possible threshold effects were seen on the Kaplan-Meier curves, particularly for cancer; individuals with less than 15% REM sleep had a higher mortality rate compared with individuals with 15% or more for each mortality outcome with odds ratios ranging from 1.20 to 1.35.
- Findings were replicated in the WSC cohort despite younger age, inclusion of women, and longer follow-up (hazard ratio, 1.13).
- A random forest model identified REM sleep as the most important sleep stage associated with survival.
"Decreased percentage REM sleep was associated with greater risk of all-cause, cardiovascular, and other noncancer-related mortality in 2 independent cohorts," concluded the authors.
The study, "Association of Rapid Eye Movement Sleep With Mortality in Middle-aged and Older Adults," is published in the journal JAMA Neurology.