Late-life sleep duration associated with amnestic mild cognitive impairment.

OBJECTIVE To examine the association between sleep duration in different stages of life and amnestic mild cognitive impairment (aMCI). DESIGN, SETTING, AND PARTICIPANTS A total of 2472 healthy elderly and 505 patients with aMCI in China were included in this study. The study analyzed the association between aMCI and sleep duration in different stages of life. MEASUREMENTS We compared sleep duration in different stages of life and analyzed the association between Montreal Cognitive Assessment scores and sleep duration by curve estimation. Logistic regression was used to evaluate the association between aMCI and sleep duration. RESULTS In the analysis, there were no results proving that sleep duration in youth (P = 0.719, sleep duration < 10 hours; P = 0.999, sleep duration ≥ 10 hours) or midlife (P = 0.898, sleep duration < 9 hours; P = 0.504, sleep duration ≥ 9 hours) had a significant association with aMCI. In the group sleeping less than 7 hours in late life, each hour more of sleep duration was associated with approximately 0.80 of the original risk of aMCI (P = 0.011, odds ratio = 0.80, 95% confidence interval = 0.68-0.95). CONCLUSIONS Among the elderly sleeping less than 7 hours, there is a decreased risk of aMCI for every additional hour of sleep.