Prospective association between sleep duration and cognitive impairment: Findings from the China Health and Retirement Longitudinal Study (CHARLS)

Abstract

ObjectiveThe association between sleep duration and cognition are inconclusive. Our study aimed to comprehensively investigate the effects of sleep duration on the risk of cognitive impairment in the middle-aged and older Chinese population.MethodsWe used the longitudinal cohort data from waves 1–4 (2011–2018) of the China Health and Retirement Longitudinal Study (CHARLS). Self-reported exposures included total sleep duration, nocturnal sleep duration, post-lunch napping, and changes in sleep duration over time according to face-to-face interviews. Cognitive function was assessed by a Chinese version of the Modified Mini-Mental State Examination (MMSE).ResultsA total of 7,342 eligible participants were included. The mean age was 61.5 ± 6.5 years, and 48.9% (3,588/7,342) were male. We identified a U-shaped association of total sleep duration as well as nocturnal sleep duration with the risk of cognitive impairment. People with 7–8 h of total sleep duration and 6–7 h of nocturnal sleep had the lowest risk of cognitive impairment. Further results showed that post-lunch napping within 2 h was beneficial to cognition and 60 min was optimal. Moreover, analyses of changes in sleep duration further supported that sleeping less or more was harmful to cognition. Notably, those “excessive-change” sleepers (from ≤6 to ≥9 h, or from ≥9 to ≤6 h) had more risks.ConclusionsKeeping 7–8 h per day was related to the lowest risk of cognitive impairment in midlife and late life, and an optimal post-lunch napping was 60 min for these stable sleepers. Especially, excessive changes in sleep duration over time led to poorer cognition. Our work highlights the importance of optimal sleep habits to cognitive function. The self-reported sleep measures limited our findings, and further studies are needed for verification.

Association between sleep duration and serum neurofilament light chain levels among adults in the United States

“…There has long been considered that sleep duration has linked to many neurodegeneration diseases [ 29 , 58 , 59 ]. Apart from some extreme status such as ABCC9 (ATP-binding cassette, sub-family C, member9) mutations [ 60 ], our result showed that sleep duration do impair neurons, but the precise pathway and link still need further exploration.…”

Funcionamiento cognitivo y calidad de sueño en adultos mayores

“…En cuanto a la valoración del funcionamiento cognitivo y el sexo, los resultados demostró que no hay una diferencia significativa entre la media de hombres (M=24.6) y mujeres (M=23.5), lo que coincide con lo obtenido por Vite y Orozco Calderón (2018) mediante la realización de un análisis lineal, usando la variable predictora sexo en relación a las funciones cognitivas, la cual no se encuentra diferencias significativas entre hombres y mujeres tanto en las puntuaciones totales como en los datos de cada subprueba. Estos resultados contrastan con lo que Liu et al (2022) al hallar en su estudio, que las mujeres, la edad avanzada y las dificultades en las actividades de la vida diaria incrementa el riesgo de padecer deterioro cognitivo.…”

“…En investigaciones realizadas en China acerca de la duración del sueño y el deterioro cognitivo Liu et al (2022) evidencia que el 50% de población adulta presenta deterioro cognitivo y la existencia de una relación entre ambas variables, observando que dormir ≤6 o ≥9 horas aumenta el riesgo de un deterioro cognitivo, así como la edad avanzada, el ser mujer, la dificultad en las actividades de la vida diaria (AVD) y la soltería. De igual manera, Song et al (2021) en su estudio en adultos mayores con deterioro cognitivo leve identifica que el 74,5% presenta alteraciones de sueño, así como una relación entre calidad de sueño y la función cognitiva.…”

Gender-and age-specific associations of sleep duration and quality with cognitive impairment in community-dwelling older adults in Anhui Province, China

“…Another long-term study, which involved 7,342 middle-aged and older adult people in China, also found a U-shaped association of the total sleep duration and nocturnal sleep duration with cognitive function, suggesting that excessively short or long sleep could increase the risk of cognitive disorder. Studies also found that people with a total sleep duration of 7-8 h per day and a nocturnal sleep duration of 6-7 h are at the lowest risk of cognitive disorders (49). A national cohort study found that increased sleep duration among older adult people was independently associated with cognitive decline, and could be affected by gender and level of education (60).…”