Suboptimal sleep efficiency and duration predict faster cognitive decline in cognitively unimpaired older adults

Abstract

AbstractBackgroundResearch indicates a role for suboptimal sleep, in cognitive ageing. An increasing, though inconsistent body of evidence has associated aspects of suboptimal self‐reported sleep quality with poorer cognitive performance. The current study investigated whether self‐reported sleep quality parameters predict the slope of domain specific cognitive performance.MethodParticipants were drawn from the Australian Imaging, Biomarkers and Lifestyle study of ageing. Linear mixed effect model (LMM) analyses were conducted on 525 cognitively unimpaired, older adults (M = 74.1, SD = 5.5, 56.4% female), characterised by apolipoprotein E (APOE) ε4 status, with baseline self‐reported sleep characteristics. Comprehensive cognitive assessments were conducted over a minimum 3 timepoints (range 29.64 ‐ 98.16 months). All models included random slopes, random intercepts, interaction effects for time, and APOE ε4 carriage, with each model adjusted based on the model of best fit for each cognitive outcome variable of interest.ResultFollowing Bonferroni correction, sleep duration <6 hours and sleep efficiency <65% in the whole cohort, and in APOE ε4 non‐carriers, forecasted accelerated decline in attention and speed of processing. In the same groups, greater sleep efficiency (%) forecasted greater preservation within the attention and speed of processing domain. No associations were observed for other sleep variables or cognitive domains of interest.ConclusionThese findings suggest a role for self‐reported suboptimal sleep efficiency and duration in the early stages of cognitive decline, represented by declining attention and speed of processing performance, in cognitively unimpaired individuals. Additionally, short sleep duration and poor sleep efficiency may increase future risk of cognitive decline independent of APOE ε4 carriage. Our findings also suggest the potential utility of self‐report screening for sleep efficiency and duration as a marker for increased risk of declining attention and speed of processing performance. Individuals with suboptimal sleep may benefit from an intervention to improve sleep efficiency and duration to lessen future risk of cognitive decline.