Keywords

aged, rural population, sleep wake disorders, sleep, mortality, sex differences

 

Authors

  1. Brostrom, Anders PhD
  2. Wahlin, Ake PhD
  3. Alehagen, Urban PhD
  4. Ulander, Martin PhD
  5. Johansson, Peter PhD

Abstract

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.