LAUSR

Introduction: Previous studies have suggested that sleep habits were associated with cardiovascular risk factors. However, there is no evidence about the relationship between sleep timing and congestive heart failure (CHF). Hypothesis: We assessed the hypothesis that the bedtime and wake-up time on weekday and weekend may be associated with incident CHF. Methods: From the Sleep Heart Health Study (registration number, NCT00005275), participants without previous heart failure were enrolled in the present prospective study. Sleep timing including bedtime and wake-up time on weekday and weekend was acquired from a self-reported Sleep Habits Questionnaire. Bedtime on weekdays and weekend was divided into >24:00, 23:01 to 24:00, 22:01 to 23:00 and ≤22:00. Wake-up time on weekdays and weekend was classified as >8:00, 7:01 to 8:00, 6:01 to 7:00 and ≤6:00. Further subgroup analysis was conducted according to sleep duration of <6h, 6-8h and >8h. Participants were followed up until the first CHF diagnosed between the date of the completed questionnaire and the final censoring date. Cox regression analysis was used to investigate the association between sleep timing and CHF. Results: A total of 4765 participants including 2207 males and 2558 females with a mean age of 63.6±11.0 years were recruited in the study. During the mean follow-up period of 11 years, 519 participants were diagnosed with CHF. The incidence of CHF in participants with weekday bedtime at >24:00 was 15.6% (69 of 441), which is higher than those with bedtime at 23:01 to 24:00 [12.7% (166 of 1306)], 22:01 to 23:00 [7.0% (128 of 1837)], and ≤22:00 [13.2% (156 of 1181)]. Participants with wake-up time on weekday at > 8:00 also had the highest incidence of CHF [19.7% (45 of 229)] than those with wake-up time at 7:01 to 8:00 [14.2% (89 of 627)], 6:01 to 7:00 [11.5% (171 of 1485)], and ≤6:00 [8.8% (214 of 2424)]. After multivariate Cox regression analyses, individuals with bedtime at >24:00 on weekdays was associated with a higher incidence of CHF (HR 1.559, 95% CI 1.151-2.113, P = 0.004) than those with bedtime at 22:01 to 23:00. And compared with participants with wake-up time at ≤6:00, those with wake-up time at > 8:00 also had an increased risk of incident CHF (HR 1.525, 95% CI 1.074-2.166, P =0.018). After further subgroup analysis, the association between bedtime at >24:00 on weekdays and incident CHF were strengthened in the participants with 6-8 hours’ sleep duration (HR 2.087, 95% CI 1.446-3.013, P <0.001). Conclusion: In conclusion, late bedtime (>24:00) and late wake-up time (>8:00) on weekdays may correlate with an increased risk of CHF. The impact of sleep timing on incident cardiovascular diseases may be worth further prospective study.