Sleep. 2019 Oct 21. pii: zsz259. doi: 10.1093/sleep/zsz259. [Epub ahead of print]
Our study objectives were to evaluate the age-related changes in actigraphy measures of sleep duration, continuity, and timing across 12 years in midlife women as they traversed the menopause, and to take into account factors affecting women’s sleep that also change with age. Black, White, and Chinese women were recruited from the Study of Women’s Health Across the Nation (SWAN) to participate in an ancillary sleep study on two occasions over 3 years apart and a third assessment 12 years after the first (N=300, mean ages, 52, 55 and 64 at the three assessments). Women had at least four consecutive nights of actigraphy (95% with 7 nights) and sleep diaries, and self-reported sleep complaints measured at each time point. Partial correlations adjusted for time between assessments across the 12 years were significant and moderate in size (rs = .33-.58). PROC MIXED/GLIMMIX multivariate models showed that sleep duration increased over time; wake after sleep onset (WASO) declined, midpoint of sleep interval increased, and sleep latency and number of sleep complaints did not change between the first and third assessments. Blacks and Whites increased in sleep duration more than Chinese. Taken together, the results of this longitudinal study suggest that sleep may not worsen in general in midlife women. Perhaps the expected negative effect of aging in midlife into early old age on sleep is overstated.