Abstract
Abstract
Introduction: S
hort and long sleep durations are significant predictors of mortality in prospective population studies. Mechanisms by which long sleep duration may increase the risk for morbidity and mortality are not known though confounding comorbidities have been suggested such as depression, low socioeconomic status, low physical activity, and other undiagnosed health conditions. Race is also associated with socioeconomic status and general overall health. We therefore sought to determine whether the association between habitual sleep duration and all-cause mortality is different between African-Americans and Caucasians in a community sample of middle-aged and older adults.
Methods
Habitual sleep duration was assessed using self-report (<7, 7–8, ≥9h/night on average) at the baseline visit of the Sleep Heart Health Study. Techniques of survival analysis were used to relate habitual sleep duration and change in sleep duration to all-cause mortality after adjusting for covariates such as age, sex, race, BMI, smoking history, prevalent hypertension, diabetes, cardiovascular disease, antidepressant medication use and sleep apnea severity. Stratified analyses by race were conducted along with the inclusion of an interaction term between race and habitual sleep duration.
Results
The sample size consisted of 4,556 Caucasians and 336 African-Americans with complete covariate data and self-reported habitual sleep duration. Compared to a sleep duration of 7-8h, habitually long (≥9h), but not short sleep duration (<7h/night), was associated with increased all-cause mortality in African-Americans with an adjusted hazards ratio of 1.97 (95% CI: 1.20, 3.23). In contrast, no association was observed between short or long sleep duration and all-cause mortality in Caucasians with adjusted hazard ratios of 0.98 (95% CI: 0.86, 1.13) and 1.11 (95% CI: 0.91, 1.35), respectively.
Conclusion
Long sleep duration is associated with all-cause mortality in African-Americans but not Caucasians.
Support (If Any)
The Sleep Heart Health Study was supported by U01HL53940, U01HL53941, U01HL53938, U01HL53916, U01HL53934, U01HL53931, U01HL53937, U01HL64360, U01HL63463, and U01HL63429. JLB is supported by an SRSF CDA, K01 DK110138 and Society in Science, The Branco Weiss Fellowship, administered by the ETH Zürich. NMP is supported by R01 HL075078 and R01 HL117167.
