Sleep Duration and Coronary Heart Disease Mortality Among Chinese Adults in Singapore: A Population-based Cohort Study

While some studies have found a positive association between both short and long sleep durations and cardiovascular disease (CVD), others have found an association only with a long or short sleep duration. In addition, there are limited data from non-Western populations on this topic. The authors examined the association between sleep duration and coronary heart disease (CHID) mortality among Chinese adults in Singapore (1993-2006), performing a prospective cohort study among 58,044 participants aged >= 45 years (55.9% women) without preexisting CVD. The main outcome of interest was CHID mortality (n = 1,416). The authors found both short and long sleep durations to be positively associated with CHID mortality, independent of smoking, alcohol intake, and body mass index. Compared with persons with a sleep duration of 7 hours (referent), the multivariable relative risk of CHID mortality for a sleep duration of <= 5 hours was 1.57 (95% confidence interval: 1.32, 1.88); for a sleep duration of >= 9 hours, it was 1.79 (95% confidence interval: 1.48, 2.17). This association persisted in subgroup analyses by sex and body mass index. In a population-based cohort of Chinese adults from Singapore, sleep durations of < 5 hours and > 9 hours (versus 7 hours) were modestly associated with CHID mortality. These results suggest that sleep duration may be an important marker for CVD.