The Relationship between Sleep Quality and Brain Amyloid Burden

Study Objectives: To evaluate the association between self-reported sleep quality and levels of brain beta-amyloid (A beta) burden, and to determine the effect of the apolipoprotein E (APOE) epsilon 4 allele on any associations found. Methods: This study is a cross-sectional analysis of 184 cognitively healthy men and women aged over 60 y. We measured sleep quality factors: specifically, sleep duration, latency (time taken to fall asleep), disturbances, efficiency, daytime dysfunction, and overall sleep quality, using the Pittsburgh Sleep Quality Index. All participants underwent A beta positron emission tomography imaging for the quantification of brain A beta burden and were APOE genotyped. Linear regression analyses were used to evaluate the relationship between sleep quality factors and brain A beta burden, adjusting for age, body mass index, cardiovascular disease, and symptoms of depression, with APOE epsilon 4 carriage entered as a moderator. Results: Of the sleep factors, longer sleep latency was associated with higher levels of brain A beta (B = 0.003 [standard error = 0.001], P = 0.02). APOE epsilon 4 allele (carrier/noncarrier) did not moderate the relationship between sleep latency and brain A beta burden. Conclusions: Our findings suggest a relationship between brain A beta burden and sleep latency, independent of APOE epsilon 4 genotype.