A Genome-Wide Genetic Association Study of Sleep Duration and Longevity
Researchers here use Mendelian randomization to attempt to better understand the relationship between sleep duration and later life mortality. As is well established, a short sleep duration correlates with raised mortality. The point of performing this sort of study of genetic variants and their relationship with specific outcomes is to try to tease out evidence for causation. Epidemiological studies can only provide correlations between sleep duration and increased mortality risk, but genetic studies can provide at least some support for the idea that short sleep duration actually causes a meaningful degree of that increased mortality risk, and isn't just a side-effect of some sort.
Poor sleep health is associated with a wide array of increased risk for cardiovascular, metabolic, and mental health problems as well as all-cause mortality in observational studies, suggesting potential links between sleep health and lifespan. However, it has yet to be determined whether sleep health is genetically or/and causally associated with lifespan.
In this study, we firstly studied the genome-wide genetic association between four sleep behaviors (short sleep duration, long sleep duration, insomnia, and sleep chronotype) and lifespan using GWAS summary statistics, and both sleep duration time and insomnia were negatively correlated with lifespan. Then, two-sample Mendelian randomization (MR) and multivariable MR analyses were applied to explore the causal effects between sleep behaviors and lifespan.
We found that genetically predicted short sleep duration was causally and negatively associated with lifespan in univariable and multivariable MR analyses, and this effect was partially mediated by coronary artery disease (CAD), type 2 diabetes (T2D), and depression. In contrast, we found that insomnia had no causal effects on lifespan. Our results further confirmed the negative effects of short sleep duration on lifespan and suggested that extension of sleep may benefit the physical health of individuals with sleep loss. Further attention should be given to such public health issues.