Sleep Duration Change and Cognitive Function: A National Cohort Study of Chinese People Older than 45 Years.

This study aimed to investigate the relationship between sleep duration and cognitive function in Chinese people older than 45 years, using data from the China Health and Retirement Longitudinal Study. The baseline survey was conducted in 2011 and the second and third wave surveys were conducted in 2013 and 2015, respectively. Multiple linear regression models were used to evaluate all associations. A total of 5811 individuals were included. No significant associations were found between short or long sleep duration at baseline and cognitive function. Compared with no change in sleep duration, a decrease in sleep duration by 2 hours or more and an increase in sleep duration by 2 hours or more were associated with worse global cognitive function, with β (95% confidence intervals [CIs]) of -0.42 (-0.70 to -0.14) and -0.34 (-0.67 to -0.01), respectively. In men, an increase of 2 hours or more in sleep duration was associated with lower global cognitive score (β = -0.64; 95% CI, -1.19 to -0.08), whereas in women, a decrease of 2 hours or more in sleep duration was associated with lower global cognitive score (β = -0.42; 95% CI, -0.78 to -0.06). Our study demonstrated that longitudinal sleep duration change was associated with cognitive function. Our findings indicate the need to consider changes in sleep duration when estimating risk and suggest that targeted strategies should be put forward for routine sleep screening and to maintain regular sleep patterns.