Association of estimated sleep duration and naps with mortality and cardiovascular events: A study of 116 632 people from 21 countries

Abstract

Aims To investigate the association of estimated total daily sleep duration and daytime nap duration with deaths and major cardiovascular events. Methods We estimated the durations of total daily sleep and daytime naps based on the amount of time in bed and self- and results reported napping time and examined the associations between them and the composite outcome of deaths and major cardiovascular events in 116 632 participants from seven regions. After a median follow-up of 7.8 years, we recorded 4381 deaths and 4365 major cardiovascular events. It showed both shorter ( 8 h/day) estimated total sleep durations were associated with an increased risk of the composite outcome when adjusted for age and sex. After adjustment for demographic characteristics, lifestyle behaviours and health status, a J-shaped association was observed. Compared with sleeping 6–8 h/day, those who slept 10 h/day, Ptrend < 0.0001, respectively]. The results were similar for each of all-cause mortality and major cardiovascular events. Daytime nap duration was associated with an increased risk of the composite events in those with over 6 h of nocturnal sleep duration, but not in shorter nocturnal sleepers ( 6 h of nighttime sleep but not in those sleeping