Sleep Duration and Risk of Ischemic Stroke in Postmenopausal Women

Department of Epidemiology, University of North Carolina School of Public Health, Chapel Hill, NC 27599-7435, USA.
Stroke (Impact Factor: 6.02). 12/2008; 39(12):3185-92. DOI: 10.1161/STROKEAHA.108.521773
Source: PubMed

ABSTRACT Many studies have shown a U-shape association between sleep duration and mortality, but epidemiological evidence linking cardiovascular diseases with habitual sleep patterns is limited and mixed.
We conducted a prospective study on 93 175 older women (aged 50 to 79 years) in the Women's Health Initiative Observational study cohort to examine the risk of ischemic stroke in relation to self-reported sleep duration. Cox models were used to investigate the putative associations, adjusting for multiple sociodemographic and lifestyle factors, depression, snoring, sleepiness symptoms, and other cardiovascular disease-related clinical characteristics.
At baseline, 8.3% of subjects had reported their sleep duration as <or=5 hours per night and 4.6% reported long duration of sleep (>or=9 hours/night). After an average of 7.5 years of follow-up, 1166 cases of ischemic stroke had occurred. Multivariable-adjusted relative risk (RR) and 95% CI for ischemic stroke (using a sleep time of 7 hours/night as the reference) were 1.14 (0.97, 1.33), 1.24 (1.04, 1.47), and 1.70 (1.32, 2.21) for women reporting <or=6, 8, and >or=9 hours of sleep. A modestly stronger association with sleep duration <or=6 hours per night (RR, 1.22; 1.03, 1.44) was noted among women without prevalent cardiovascular disease at baseline. Our analyses also reveal that the adverse effect of long sleep is likely independent of the increased risk for ischemic stroke associated with frequent snoring and sleepiness (RR, 1.31; 1.00, 1.72).
Habitual sleep patterns are important neurobehavioral determinants of risk for ischemic stroke in postmenopausal women. The underlying neurobiology and mechanistic mediators for the putative adverse effect of long sleep (>or=9 hours/night) need further elucidation.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The Women's Health Initiative (WHI) clinical trials of estrogen with or without progestin versus placebo in 27,341 postmenopausal women are the largest randomized, placebo-controlled, double-blind clinical trials to look at the effect of hormone therapy on the outcomes of stroke, dementia, and cognition. Data from a parallel prospective observational study of 93,676 women examine biomarkers and risk factors associated with stroke. We summarize the results of 29 published articles in the WHI with stroke or cognition as outcomes of interest. Estrogen alone or in combination with progestin resulted in approximately 50% excess risk of ischemic stroke and in a 76% excess risk of dementia in women 65 years or older. Other risk factors for stroke identified in the WHI were panic attacks, depression, use of antidepressants (particularly selective serotonin reuptake inhibitors for hemorrhagic but not ischemic stroke), high triglycerides, low walking speed, long sleep duration, certain inflammatory factors, and systolic blood pressure variability. Hormone therapy has adverse effects on the brain as manifested by higher risks of stroke and dementia. Additional risk factors for stroke identified in WHI should be followed up to determine if reversing them would result in lower stroke rates.
    Seminars in Reproductive Medicine 11/2014; 32(6):438-446. DOI:10.1055/s-0034-1384627 · 3.00 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The association between sleep duration and predicted cardiovascular risk has been poorly characterized. The objective of this study was to examine the association between self-reported sleep duration and predicted 10-year cardiovascular risk among US adults. Data from 7690 men and nonpregnant women who were aged 40 to 79 years, who were free of self-reported heart disease and stroke, and who participated in a National Health and Nutrition Examination Survey from 2005 to 2012 were analyzed. Sleep duration was self-reported. Predicted 10-year cardiovascular risk was calculated using the pooled cohort equations. Among the included participants, 13.1% reported sleeping ≤5 hours, 24.4% reported sleeping 6 hours, 31.9% reported sleeping 7 hours, 25.2% reported sleeping 8 hours, 4.0% reported sleeping 9 hours, and 1.3% reported sleeping ≥10 hours. After adjustment for covariates, geometric mean-predicted 10-year cardiovascular risk was 4.0%, 3.6%, 3.4%, 3.5%, 3.7%, and 3.7% among participants who reported sleeping ≤5, 6, 7, 8, 9, and ≥10 hours per night, respectively (PWald chi-square<0.001). The age-adjusted percentages of predicted cardiovascular risk ≥20% for the 6 intervals of sleep duration were 14.5%, 11.9%, 11.0%, 11.4%, 11.8%, and 16.3% (PWald chi-square=0.022). After maximal adjustment, however, sleep duration was not significantly associated with cardiovascular risk ≥20% (PWald chi-square=0.698). Mean-predicted 10-year cardiovascular risk was lowest among adults who reported sleeping 7 hours per night and increased as participants reported sleeping fewer and more hours. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.
    Journal of the American Heart Association 10/2014; 3(6). DOI:10.1161/JAHA.114.001454 · 2.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background and Purpose-Dietary potassium has been associated with lower risk of stroke, but there are little data on dietary potassium effects on different stroke subtypes or in older women with hypertension and nonhypertension. Methods-The study population consisted of 90 137 postmenopausal women aged 50 to 79 at enrollment, free of stroke history at baseline, followed up prospectively for an average of 11 years. Outcome variables were total, ischemic, and hemorrhagic stroke, and all-cause mortality. Incidence was compared across quartiles of dietary potassium intake, and hazard ratios were obtained from Cox proportional hazards models after adjusting for potential confounding variables, and in women with hypertension and nonhypertension separately. Results-Mean dietary potassium intake was 2611 mg/d. Highest quartile of potassium intake was associated with lower incidence of ischemic and hemorrhagic stroke and total mortality. Multivariate analyses comparing highest to lowest quartile of potassium intake indicated a hazard ratio of 0.90 (95% confidence interval, 0.85-0.95) for all-cause mortality, 0.88 (95% confidence interval, 0.79-0.98) for all stroke, and 0.84 (95% confidence interval, 0.74-0.96) for ischemic stroke. The effect on ischemic stroke was more apparent in women with nonhypertension among whom there was a 27% lower risk with hazard ratio of 0.73 (95% confidence interval, 0.60-0.88), interaction P<0.10. There was no association with hemorrhagic stroke. Conclusions-High potassium intake is associated with a lower risk of all stroke and ischemic stroke, as well as all-cause mortality in older women, particularly those who are not hypertensive.
    Stroke 09/2014; 45(10). DOI:10.1161/STROKEAHA.114.006046 · 6.02 Impact Factor

Full-text (2 Sources)

Available from
May 22, 2014