Global cognitive function declined faster in people with either very short or very long sleep duration than in people who slept 7 hours a night, combined data from England and China showed.
Over 100,000 person-years of follow-up, cognitive z scores had a pooled β of -0.022 (95% CI -0.035 to -0.009 SD per year) with 4 or fewer hours of sleep a night and a pooled β of -0.033 (95% CI -0.054 to -0.011 SD per year) with 10 or more hours, in adjusted analyses, reported Wuxiang Xie, PhD, of the Peking University Clinical Research Institute in Beijing, and co-authors.
Extreme sleep duration also was associated with lower cognitive function at baseline, they wrote in JAMA Network Open.
Findings were consistent in English and Chinese cohorts, despite cultural differences. An inverted U-shaped association between sleep duration and change in global cognition score emerged, which also was seen in longitudinal