Association Between Sleep Duration and Cognitive Decline

An association between sleep duration and the trajectory of cognitive decline has not been conclusively demonstrated.

To investigate the association between sleep duration and cognitive decline by a pooled analysis of 2 nationally representative aging cohorts. Design, Setting, and Participants: A pooled cohort study using data from waves 4 to 8 (2008-2009 to 2016-2017) in the English Longitudinal Study of Ageing and waves 1 to 3 (2011 to 2015) in the China Health and Retirement Longitudinal Study in a population-based setting. Participants were 2 randomly enrolled cohorts comprising 28 756 individuals living in England who were 50 years or older and those living in China who were 45 years or older. Exposure: Self-reported sleep duration per night according to face-to-face interviews. Main Outcomes and Measures: Global cognitive z scores were calculated according to immediate and delayed recall test, an animal fluency test, the serial sevens test, an intersecting pentagon copying test, and a date orientation test.