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Cumulative effects of sleep quality on risk for incident mild cognitive impairment (MCI): Results from the Einstein Aging Study (EAS) cohort
Author(s) -
Derby Carol A,
Wang Cuiling,
Katz Mindy J,
Lipton Richard B,
Buxton Orfeu M
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.044861
Subject(s) - cohort , dementia , medicine , gerontology , cohort study , sleep (system call) , risk factor , psychology , disease , computer science , operating system
Background Sleep deficiency and sleep disorders are common in older adults and have been linked to cognitive decline and dementia risk. Better understanding the association of sleep patterns over time with onset of early cognitive changes may facilitate interventions to prevent AD and dementia. Few studies have reported on the association of cumulative longitudinal measures of sleep quality with onset of mild cognitive impairment (MCI). The Einstein Aging Study (EAS) longitudinal cohort provided the opportunity to examine whether cumulative exposure to poor sleep quality predicts incident MCI in a community‐based cohort. Method Analyses include 639 EAS participants from Bronx, NY, age > 70 years (mean 78.6± 5.3, 62% female, 65% White/28% African American), without MCI or dementia at initial assessment and with at least one annual follow‐up. Sleep was assessed annually using the Medical Outcomes Study of Sleep (MOS‐S) questionnaire. Factor analysis of the 12 MOS‐S items yielded three factor scores based on the sum of items with loading ≥ 0.5, such that higher scores indicate better sleep quality. Factors included were: Daytime somnolence, Disturbed sleep and Perceived sleep adequacy. Trajectories of these indices over annual follow‐up were examined using linear mixed effects models. The associations of concurrent and cumulative sleep quality indices on MCI risk were estimated from Cox models with time dependent exposure, adjusting for age, sex, education and race/ethnicity. Result Over a mean of 4.4 annual assessments, 162 cases of incident MCI occurred. During follow‐up, sleep adequacy increased (p < 0.0001), daytime somnolence decreased (p = 0.025) and sleep disturbance showed no significant pattern of change (p > 0.05. Cox models showed no association between concurrent indices of sleep quality and incident MCI (all p > 0.05). However, cumulative effects of sleep quality on MCI risk were observed. Over time, less daytime somnolence, less frequent disturbed sleep and better sleep adequacy were associated with reduced risk of incident MCI (HR’s: Somnolence = 0.97, Disturbed = 0.98), Adequacy = 0.97; all p< 0.0001). Conclusion Adverse effects of poor sleep quality on cognition may be cumulative suggesting that improving sleep in older adults may prevent or delay MCI onset.