Sex-Specific Associations Between Self-reported Sleep Duration, Cardiovascular Disease, Hypertension, and Mortality in an Elderly Population

Background: Both short and long sleep durations have been associated to increased mortality. Knowledge about sex-specific differences among elderly regarding associations between sleep duration, cardiovascular health, and mortality is sparse. Objective: The aims of this study are to examine the association between self-reported sleep duration and mortality and to investigate whether this association is sex specific and/or moderated by cardiovascular morbidity, and also to explore potential mediators of sleep duration effects on mortality. Methods: A population-based, observational, cross-sectional design with 6-year follow-up with mortality as primary outcome was conducted. Self-rated sleep duration, clinical examinations, echocardiography, and blood samples (N-terminal fragment of proBNP) were collected. A total of 675 persons (50% women; mean age, 78 years) were divided into short sleepers (<= 6 hours; n = 231), normal sleepers (7-8 hours; n = 338), and long sleepers (>= 9 hours; n = 61). Data were subjected to principal component analyses. Cardiovascular disease (CVD) and hypertension factors were extracted and used as moderators and as mediators in the regression analyses. Results: During follow-up, 55 short sleepers (24%), 68 normal sleepers (20%), and 21 long sleepers (34%) died. Mediator analyses showed that long sleep was associated with mortality in men (hazard ratio [HR], 1.8; P = .049), independently of CVD and hypertension. In men with short sleep, CVD acted as a moderator of the association with mortality (HR, 4.1; P = .025). However, when using N-terminal fragment of proBNP, this effect became nonsignificant (HR, 3.1; P = .06). In woman, a trend to moderation involving the hypertension factor and short sleep was found (HR, 4.6; P = .09). Conclusion: Short and long sleep duration may be seen as risk markers, particularly among older men with cardiovascular morbidity.