0726 Longitudinal Changes in 24-h Sleep-wake Patterns and All-cause Mortality in Older Women

Abstract Introduction Sleep-wake patterns generally worsen with advancing age. However, little is known about changes in sleep and circadian patterns in very old adults, and how these changes may be associated with future mortality risk. We examined the association between changes in 24-hour sleep-wake patterns and risk of all-cause mortality in community-dwelling older women. Methods We studied 702 women (meanSD age = 82.92.7 years) who had nighttime sleep (total sleep time TST; sleep efficiency; and wake after sleep onset), napping (duration and frequency) and 24-hour rest-activity rhythm (acrophase, amplitude, mesor, and pseudo-F regularity) parameters assessed using 4-night/5-day actigraphy at baseline (2002-04) and again 5 years later (2007-08), after which all-cause mortality information was collected using death certificates. The 5-year changes in all parameters were calculated and included in a hierarchical clustering on principal components analysis to identify patterns of sleep changes. We used Cox proportional hazards models to evaluate the longitudinal associations between patterns of sleep changes and all-cause mortality. Results During a mean follow-up time of 2.1 years, 90 (12.8%) women died. We identified three patterns of sleep changes: 159 (22.6%) women with Pattern 1 (increased nighttime and daytime sleep and reduced circadian rhythmicity), 233 (33.2%) with Pattern 2 (decreased nighttime sleep quality and duration and reduced circadian rhythmicity), and 310 (44.2%) with Pattern 3 (stable sleep or slight improvement). After adjustment for age, education, body mass index, diabetes, hypertension, heart attack, antidepressant use, and baseline cognition, women with Pattern 1 HR (95% CI) = 2.23 (1.25,4.01) or Pattern 2 HR (95% CI) = 2.26 (1.35,3.79) had more than twice the mortality risk compared to women with Pattern 3. When individual sleep change parameters were examined, the association with mortality risk was particularly strong for increased TST, napping duration, and reduced circadian amplitude and regularity. Conclusion Among women in their 80s, those with increased nighttime and daytime sleep duration, decreased nighttime sleep quality or reduced circadian rhythmicity over 5 years had double the risk of all-cause mortality compared to those with stable sleep. Sleep changes in late life may be important marker or risk factor for adverse aging outcomes. Support (if any)