Sleep duration and risk of all-cause mortality: a systematic review and meta-analysis.

AIMS: To determine the association between the sleep duration and the risk of all-cause mortality in adults. METHODS: A search strategy was conducted in the MEDLINE, CENTRAL, EMBASE and LILACS databases. Searches were also conducted in other databases and unpublished literature. Cohort studies were included without language, time or setting restrictions. The risk of bias was evaluated with a modified Cochrane Collaboration's tool. An analysis of random effects was conducted. The primary outcome was all-cause mortality. The measure of the effect was the risk difference (RD) with a 95% confidence interval (CI). The planned comparisons were 7-9 h of sleep v. <7 h and the same reference v. >9 h. RESULTS: Thirty-nine studies were included in our qualitative analysis, regarding the quantitative analysis, 19 studies were included in <7 v. 7-9 h analysis, and 18 studies in the >9 v. 7-9 h. A low risk of bias was shown for most of the study items. The overall RD for all-cause mortality was 0.09 (95% CI 0.07-0.11) favouring the >9 h group compared with our reference. In contrast, no differences were found between the <7 h and the reference sleep duration groups (RD 0.00, 95% CI 0.00-0.01). CONCLUSION: We found a probable association of long sleep duration and higher mortality; however, it could reflect an underlying systemic or neurological disease that cause sleep fragmentation, deterioration in quality and micro-awakenings.

Impact of the Metabolic Syndrome on Mortality is Modified by Objective Short Sleep Duration.

BACKGROUND: To examine whether objective sleep duration is an effect modifier of the impact of metabolic syndrome (MetS) on all-cause and cardiovascular disease/cerebrovascular mortality. METHODS AND RESULTS: We addressed this question in the Penn State Adult Cohort, a random, general population sample of 1344 men and women (48.8±14.2 years) who were studied in the sleep laboratory and followed up for 16.6±4.2 years. MetS was defined by the presence of 3 or more of obesity (≥30 kg/m2), elevated total cholesterol (≥200 mg/dL), triglycerides (≥150 mg/dL), fasting glucose (≥100 mg/dL), and blood pressure (≥130/85 mm Hg). Polysomnographic sleep duration was classified into clinically meaningful categories. Among the 1344 participants, 22.0% of them died during the follow-up. We tested the interaction between MetS and polysomnographic sleep duration on mortality using Cox proportional hazard models controlling for multiple potential confounders (P<0.05). The hazard ratios (95% CI) of all-cause and cardiovascular disease/cerebrovascular mortality associated with MetS were 1.29 (0.89-1.87) and 1.49 (0.75-2.97) for individuals who slept ≥6 hours and 1.99 (1.53-2.59) and 2.10 (1.39-3.16) for individuals who slept <6 hours. Interestingly, this effect modification was primarily driven by the elevated blood pressure and glucose dysregulation components of MetS. CONCLUSIONS: The risk of mortality associated with MetS is increased in those with short sleep duration. Short sleep in individuals with MetS may be linked to greater central autonomic and metabolic dysfunction. Future clinical trials should examine whether lengthening sleep improves the prognosis of individuals with MetS.

Sleep duration and mortality in the elderly: a systematic review with meta-analysis.

OBJECTIVE: The purpose of our study was to evaluate the association between short and long sleep duration and all-cause and cardiovascular mortality among elderly individuals. DESIGN: Systematic review and meta-analysis of population-based cohort studies. SETTING: Articles were retrieved from international and national electronic databases. STUDY SELECTION: Studies were identified in PubMed, EMBASE, LILACS (Latin American and Caribbean Health Sciences Literature), IBECS (Bibliographic Index on Health Sciences from Spain) and CAPES (PhD thesis repository) between 1980 and 2015. Studies which met all criteria were eligible: participants aged 60 years or over, assessment of sleep duration as 24 h, nighttime or daytime sleep, evaluation of all-cause or cause-specific mortality, population-based cohort studies conducted on representative samples. There was no language restriction and studies published as abstracts were excluded. DATA EXTRACTION: Data were analysed using the Comprehensive Meta-Analysis software (V.3.3.070), and summary estimates (relative risk (RR), 95% CI) were calculated using a random effects model. Heterogeneity and consistency were evaluated through Cochran's Q and the I(2) statistics, respectively, and sensitivity analyses were conducted. PRIMARY AND SECONDARY OUTCOME MEASURES: All-cause and cardiovascular mortality. RESULTS: Overall, 27 cohort studies were selected, comprising >70,000 elderly individuals, and followed up from 3.4 to 35 years. In the pooled analysis, long and short sleep duration were associated with increased all-cause mortality (RR 1.33; 95% CI 1.24 to 1.43 and RR 1.07; 95% CI 1.03 to 1.11, respectively), compared with the reference category. For cardiovascular mortality, the pooled relative risks were 1.43 (95% CI 1.15 to 1.78) for long sleep, and 1.18 (95% CI 0.76 to 1.84) for short sleep. Daytime napping ≥ 30 min was associated with risk of all-cause mortality (RR 1.27; 95% CI 1.08 to 1.49), compared with no daytime sleep, but longer sleep duration (≥ 2.0 h) was not (RR 1.34; 95% CI 1.95 to 1.90). CONCLUSIONS: Among elderly individuals, long and short sleep duration are associated with increased risk for all-cause mortality. Long sleep duration is associated with cardiovascular mortality.

Cronobiología, sueño y depresión / Chronobiology, sleep and depression

Luego de una actualización sobre diversos aspectos del ciclo vigilia‑sueño, en el presente trabajo se analiza las consecuencias que tiene su alteración sobre el organismo. Además de las consecuencias neuroendócrinas y cardiovasculares, se hace especialmente hincapié en su efecto sobre el estado de ánimo, y la evidencia que surge sobre su vinculación con los episodios depresivos y trastornos bipolares. Finalmente,se establece, como elemento a tener en cuentapara la terapéutica de dicha patología, el uso de medicación que no solo actúe sobre los neurorreceptores, sino que también reestablezca un ordenado ciclo vigilia‑sueño, como forma de evitar la cronificación y agravamiento de los trastornos anímicos.

Cronobiología, sueño y depresión / Chronobiology, sleep and depression

Luego de una actualización sobre diversos aspectos del ciclo vigilia‑sueño, en el presente trabajo se analiza las consecuencias que tiene su alteración sobre el organismo. Además de las consecuencias neuroendócrinas y cardiovasculares, se hace especialmente hincapié en su efecto sobre el estado de ánimo, y la evidencia que surge sobre su vinculación con los episodios depresivos y trastornos bipolares. Finalmente,se establece, como elemento a tener en cuentapara la terapéutica de dicha patología, el uso de medicación que no solo actúe sobre los neurorreceptores, sino que también reestablezca un ordenado ciclo vigilia‑sueño, como forma de evitar la cronificación y agravamiento de los trastornos anímicos.

Self-reported sleep characteristics and mortality in older adults of mexican origin: results from the Hispanic established population for the epidemiologic study of the elderly.

OBJECTIVES: To determine how poor sleep affects the health of older ethnic minorities. DESIGN: Cross-sectional study involving a population-based survey. SETTING: Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE) survey conducted in the southwestern United States. PARTICIPANTS: Two thousand two hundred fifty-six Mexican-American men and women aged 65 and older. MEASUREMENTS: The association between self-reported sleep problems and mortality over a 15-year period in a population based sample of older Mexican Americans was examined. Using five waves of data (1993-2008) from the H-EPESE, Cox proportional hazard models stratified according to sex were used to model the risk of death as a function of chronic sleep problems. RESULTS: Having any sleeping problems during the last month was associated with greater risk of mortality (hazard ratio = 1.14, 95% confidence interval = 1.00-1.29) in unadjusted models, although the association was attenuated after accounting for covariates. CONCLUSIONS: Similar factors explained the association between sleep and mortality in men and women: health behaviors, depressive symptoms, and health conditions. These factors are related to stress, and both may lead to poor sleep quality. Research is needed to better understand the factors moderating the relationship between sleep, mortality, and sex.