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Difficulty falling asleep and non-restorative sleep are probably associated with a risk of all-cause and
Insomnia, most commonly characterized by difficulty falling asleep, difficulty maintaining sleep, or early morning awakening, is an important public health problem with substantial medical, psychiatric, and financial ramifications [1]. Epidemiological surveys have reported a prevalence of insomnia symptoms in between 35% and 70% of the general adult population [2]. The total costs associated with insomnia exceed $100 billion annually in the United States of America [3]. Systematic reviews have established the association between insomnia and an increased risk of mental or medical disorders including depression [4], dementia [5], nonalcoholic fatty liver disease [6], hypertension [7], cardiovascular disease [8], [9], [10], and perinatal depressive symptoms [11].
Increasing evidence has also suggested that sleep disorders may be associated with mortality. Several meta-analyses have presented evidence that longer or shorter sleep duration is associated with a higher risk of mortality [12], [13], [14], ∗[15]. Published cohort studies have reported that some insomnia symptoms may be independently associated with mortality; these findings have, however, proved inconsistent [16], ∗[17], [18], [19], ∗[20], [21], ∗[22], [23], [24]. For example, although several studies have reported associations between insomnia symptoms and mortality [16], ∗[17], [18], [19], [21], others have not ∗[20], ∗[22], [23], [24]. Varying assessment methods of insomnia symptoms, and approaches to adjusted analysis may, at least in part, explain these inconsistencies.
To clarify this issue, we performed a systematic review and meta-analysis of prospective cohort studies from the general population. The aim of this was to comprehensively assess the association between mortality from all-cause, cardiovascular, and cancer and both insomnia disorder and individual insomnia symptoms (difficulty falling asleep, difficulty maintaining sleep, early morning awakening, and non-restorative sleep).
Our report follows the meta-analysis of observational studies in epidemiology (MOOSE) checklist [25] and the study protocol registered with PROSPERO: CRD42018086625.
Our search yielded 6389 records of which 74 proved potentially eligible on the basis of titles and abstracts (see Supplementary Text S3 for the reasons and lists of references excluded in full-text screening) and 31 articles including 29 cohort studies proved eligible (Supplementary Fig. S1) [16], ∗[17], [19], ∗[20], [21], ∗[22], [23], [24], ∗[33], ∗[34], [35], ∗[36], [37], ∗[38], [39], [40], [41], ∗[42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55]. Lallukka
Sleep is a critical determinant of health and well-being. Poor sleep is a common problem with 25% of adults in the United States of America, reporting insufficient sleep or rest, for at least 15 of every 30 d [57]. This meta-analysis is the first to quantify the magnitude and certainty of the association between insomnia disorder/symptoms and mortality among adults aged ≥18 yrs old. We found that, with moderate to high certainty, difficulty falling asleep and non-restorative sleep were
Our findings indicate that difficulty falling asleep and non-restorative sleep are probably associated with all-cause mortality and cardiovascular disease mortality. We did not find associations with other aspects of insomnia symptoms and mortality, nor with any aspect and cancer mortality (though quality of evidence for this outcome was generally low or very low). Difficulty falling asleep and non-restorative sleep are probably associated with a risk of all-cause andPractice points
The authors do not have any conflicts of interest to declare.
Prof. Kehu Yang was supported by the Fundamental Research Funds for the Central Universities - Research on Evidence-Based Social Science (16LZUJBWTD013) and Dr. Long Ge was supported by Chinese high-level public university post-graduate project from China Scholarship Council. The study sponsors had no any role in study design, data collection and analysis, decision to publish, or preparation this manuscript.
The most important references are denoted by an asterisk.