Alzheimer s disease genetic risk and sleep phenotypes: association with more slow-waves and daytime sleepiness
A bidirectional detrimental relationship between sleep alteration and Alzheimer9s disease (AD) has been reported in cognitively normal older adults. Here, we tested whether a similar association could be detected in young adults, decades before typical AD symptom onset. We investigated associations between sleep endophenotypes and genome-wide Polygenic Risk Scores (PRS) for AD in 363 young men (22.1 +/- 2.7y) devoid of sleep and cognitive disorders. AD PRS was associated with higher slow wave energy, a marker of sleep need, during habitual sleep and following sleep loss, and, potentially, with the relative increase in slow wave energy following sleep deprivation, reflecting sleep homeostasis. Furthermore high AD PRS was correlated with higher daytime sleepiness. These results imply that sleep features may be associated with AD liability in young adults and suggest that, contrary to older adults, denser and/or more intense sleep slow waves are associated with AD risk in early adulthood.