Evidence map›Paper›PMID 26158892›Full record

SynthesisSleep2015

Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis.

Tomohide Yamada, Kazuo Hara, Nobuhiro Shojima, Toshimasa Yamauchi, Takashi Kadowaki

Abstract readMeta-Analysis
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Sleep, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 77 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
77citing papers in PubMed, 5 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

77 citing papers in PubMed, 5 syntheses or guidelines pooled it.

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  18. The Beauty Sleep to Keep a Healthy Liver.International journal of molecular sciences · 2025
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17 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors.

Tomohide YamadaDepartment of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Japan.
Kazuo HaraDepartment of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Japan.
Nobuhiro ShojimaDepartment of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Japan.
Toshimasa YamauchiDepartment of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Japan.
Takashi KadowakiDepartment of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

STUDY

objectivesTo summarize evidence about the association between daytime napping and the risk of cardiovascular disease and all-cause mortality, and to quantify the potential dose-response relation.

designMeta-analysis of prospective cohort studies. METHODS AND

resultsElectronic databases were searched for articles published up to December 2014 using the terms nap, cardiovascular disease, and all-cause mortality. We selected well-adjusted prospective cohort studies reporting risk estimates for cardiovascular disease and all-cause mortality related to napping. Eleven prospective cohort studies were identified with 151,588 participants (1,625,012 person-years) and a mean follow-up period of 11 years (60% women, 5,276 cardiovascular events, and 18,966 all-cause deaths). Pooled analysis showed that a long daytime nap (≥ 60 min/day) was associated with a higher risk of cardiovascular disease (rate ratio [RR]: 1.82 [1.22-2.71], P = 0.003, I(2) = 37%) compared with not napping. All-cause mortality was associated with napping for ≥ 60 min/day (RR: 1.27 [1.11-1.45], P < 0.001, I(2) = 0%) compared with not napping. In contrast, napping for < 60 min/day was not associated with cardiovascular disease (P = 0.98) or all-cause mortality (P = 0.08). Meta-analysis demonstrated a significant J-curve dose-response relation between nap time and cardiovascular disease (P for nonlinearity = 0.01). The RR initially decreased from 0 to 30 min/day. Then it increased slightly until about 45 min/day, followed by a sharp increase at longer nap times. There was also a positive linear relation between nap time and all-cause mortality (P for non-linearity = 0.97).

conclusionsNap time and cardiovascular disease may be associated via a J-curve relation. Further studies are needed to confirm the efficacy of a short nap.

Indexed as

Cause of DeathAgedCardiovascular DiseasesFemaleHumansMaleMiddle AgedProspective StudiesRisk FactorsSleepTime Factorsall-cause mortalitycardiovascular diseasemeta-analysisnappingsiesta

Identifiers

PMID26158892
PMCPMC4667384

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.