0175 Sleep characteristics in older adults and the risk of Alzheimer’s Disease mortality: The NIH-AARP Diet and Health Study

Abstract

Abstract Introduction Alzheimer’s Disease (AD) is the most common form of dementia (1) and the 6th leading cause of death in the U.S. (2). Additionally, it is estimated that currently 5 million individuals are living with AD in the U.S. and this number is expected to triple by 2050 (3). Decades of research has identified various risk factors for AD and a wide array of cardiometabolic risk factors, such as hypertension, type 2 diabetes, metabolic syndrome and obesity (4, 5, 6, 7). Several behavioral factors have also been suggested to play a protective role against AD, including Mediterranean-type diet (8), physical activity (9), and cognitively stimulating activities (10, 11). More recently, growing evidence has pointed sleep deficiency as a modifiable risk factor for AD. (12). Methods The purpose of our study was to determine if sleep and napping were associated with AD mortality. We used data from the NIH-AARP Diet and Health Study. Sleep duration and napping were self-reported and AD death were ascertained via linkage to the National Death Index. Of 566,398 members (aged 50-71) who completed baseline questionnaire in 1995-1996, 337,373 participants were included (195,656 men and 137,018 women). Results Long sleep and napping were both associated with increased AD mortality. Specifically, 9+ hours of sleep was associated with 50% increase (Hazard Ratio 1.50, 95% CI (1.17-1.92)) in AD mortality when compared 7-8 hours, while napping for 1+ hours was associated with 29% increase (1.29 (1.08, 1.55)) when compared to no napping. Results appeared to be stronger in men and remained after removing AD deaths within first 5 years after baseline. Conclusion The results of this study showed that 9+ hours sleep duration was associated with a 50% increase in AD mortality risk when compared to people who slept between 7 and 8 hours, particularly in men. Additional longitudinal studies that follow middle-aged adults through death and include objective measures of sleep and AD related biomarkers are needed to further elucidate the mechanisms contributing to cognitive decline and AD death. Such studies would be useful for informing interventions designed to reduce risk of AD and AD-related death. Support (If Any)