Elsevier

Sleep Medicine

Volume 50, October 2018, Pages 48-54
Sleep Medicine

Original Article
The association of sleep duration and quality with all-cause and cause-specific mortality in the Women’s Health Initiative

https://doi.org/10.1016/j.sleep.2018.05.015Get rights and content

Highlights

  • Short and long sleep duration were associated with increased total mortality.

  • Insomnia was not associated with mortality.

  • Use of sleep aids was positively association with mortality.

Abstract

Background/Objective

Many studies have shown a U-shaped association of sleep duration with mortality; however, this association is difficult to interpret owing to possible reverse causation, residual confounding, and measurement issues. We used data from the Women's Health Initiative to examine the associations of sleep duration, insomnia, and use of sleep aids with death from cardiovascular disease (CVD), cancer, “other” causes, and all causes combined.

Methods

Cox proportional hazards models were used in the analysis of baseline data and in time-dependent analyses of repeated measures to estimate associations of sleep-related factors with mortality. Among 158,203 women with information regarding sleep, 30,400 total deaths, 8857 CVD deaths, 9284 cancer deaths, and 11,928 other deaths were ascertained over a median of 17.8 years.

Results

In both baseline and time-dependent analyses, both short (≤5 h) and long sleep (≥9 h) durations were associated with increased risk of total, CVD, and “other” deaths, but not with cancer deaths. Insomnia showed no association with mortality, whereas use of sleep medications was associated with an increased mortality risk.

Conclusions

While our findings showed a small but robust association of sleep duration with mortality in postmenopausal women, studies including objective measurements of sleep quality and efficiency are needed to clarify these associations.

Introduction

Modern society has had a profound influence on our sleep habits. Since the 1960s, the average reported nightly sleep duration in the U.S. has decreased from more than 8 h–6.5 h per night, with 20–30% of middle-aged Americans reporting an average nightly sleep duration of less than 6 h [1]. Poor sleep quality and quantity have been associated with a range of adverse health outcomes, including diabetes, cardiovascular disease, and cancer as well as elevated total and cause-specific mortality [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15].

Over the past 40 years, numerous prospective studies have shown a U-shaped association between sleep duration and mortality, with an increased risk of all-cause and cause-specific mortality among both short and long sleepers, compared with those sleeping 7–8 h per night [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]. However, the association is difficult to interpret owing to limitations of these studies, including: variation in categories of sleep duration by study; inconsistencies in the findings by sex and age; the availability of only a single assessment of sleep duration (at baseline) in all but a few studies [6], [7]; the failure of some studies to take potential confounders or effect modifiers (eg, poor pre-existing health) into account; and the failure of most studies to examine sleep quality [6], [12], [15].

Therefore, we used data from the Women's Health Initiative(WHI) cohort to examine sleep duration, insomnia, and use of sleep medications in relation to total and cause-specific mortality. The availability of measurements of sleep-related factors at multiple time points as well as information on medical history at enrollment and on conditions reported during follow-up enabled analysis of the independent and joint effects sleep duration and sleep quality on mortality.

Section snippets

Dataset

The Women's Health Initiative is a large, multicenter study designed to improve our understanding of the determinants of major chronic diseases in postmenopausal women. It was originally composed of a clinical trial component (CT, n = 68,132) and an observational study component (OS, n = 93,676) [16]. The CT component included four randomized controlled intervention studies: hormone therapy (two trials), low-fat dietary modification, and calcium + vitamin D supplementation. Women between the

Results

Women with the lowest and highest number of hours of sleep per night had higher BMI and systolic blood pressure, higher levels of depression, use of sleep aids, fair-to-poor health, and a history of diabetes, CVD, or cancer (Table 1). Women at the extremes of the distribution of sleep hours also had lower levels of physical activity and were less likely to white, to be college-graduates, or to report ever use of hormone therapy. Women with insomnia had higher BMI, more pack-years of smoking,

Discussion

In the present study, both short and long sleep duration measured at the baseline visit were associated with increased risk of total mortality, CVD mortality, and other mortality, but not with cancer mortality. Insomnia reported at baseline showed a weak inverse association with total and CVD mortality, whereas use of sleep aids was associated with increased risk of total mortality, CVD mortality, and other mortality. The pattern of associations was generally similar in sensitivity analyses

Acknowledgments

Additional Contributions: We thank the Women's Health Initiative investigators, staff, and the trial participants for their outstanding dedication and commitment.

Women's Health Initiative Investigators.

Program Office: (National Heart, Lung, and Blood Institute, Bethesda, MD) Jacques Roscoe, Shari Ludlum, Dale Burden, Joan McGowan, Leslie Ford, and Nancy Geller.

Clinical Coordinating Center: (Fred Hutchinson Cancer Research Center, Seattle, WA) Garnet Anderson, Ross Prentice, Andrea LaCroix, and

References (41)

  • J.D. Curb et al.

    Outcomes ascertainment and adjudication methods in the Women's Health Initiative

    Ann Epidemiol

    (2003)
  • Y. Li et al.

    Potential biochemical pathways for the relationship between sleep duration and mortality

    Sleep Med

    (2013)
  • D.J. Foley

    An epidemiological perspective on one tale of a two-tailed hypothesis

    Sleep Med Rev

    (2004)
  • M.R. Irwin et al.

    Sleep disturbance, sleep duration, and inflammation: a systematic review and meta-analysis of cohort studies and experimental sleep deprivation

    Biol Psych

    (2016)
  • A. Briançon-Marjollet et al.

    The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

    Diabetol Metabol Syndr

    (2015)
  • G. Twig et al.

    Sleep quality and risk of diabetes and coronary artery disease among young men

    Acta Diabetol

    (2016)
  • D.F. Kripke et al.

    Short and long sleep and sleeping pills. Is increased mortality associated?

    Arch Gen Psychiatry

    (1979)
  • D.L. Wingard et al.

    Morality risk associated with sleeping patterns among adults

    Sleep

    (1983)
  • D.F. Kripke et al.

    Mortality associated with sleep duration and insomnia

    Arch Gen Psychiatry

    (2002)
  • C. Hublin et al.

    Sleep and mortality: a population-based 22-year follow-up study

    Sleep

    (2007)
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