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Cited by 130Sleep and related disordersCircadian rhythm and melatoninSleep and Work-Related Fatigue

Sleep duration and metabolic syndrome in adult populations: a meta-analysis of observational studies

Open access
Ju, S-Y, Choi, W-S·2013·Nutrition & Diabetes
DOI 10.1038/nutd.2013.8PMC PMC3671750
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Abstract

OBJECTIVE: Epidemiological studies have repeatedly investigated the association between sleep duration and metabolic syndrome. However, the results have been inconsistent. This meta-analysis aimed to summarize the current evidence from cross-sectional and prospective cohort studies that evaluated this. DATA SOURCES: Relevant studies were identified by systematically searching the PubMed, Cochrane CENTRAL, EMBASE and PsycINFO databases through November 2012 without language restriction. STUDY SELECTION: We identified 12 cross-sectional studies with 76 027 participants including 14 404 cases of metabolic syndrome, and 3 cohort studies with 2055 participants and 283 incident cases of metabolic syndrome. RESULTS: For short sleep durations (<5 to 6 h), the odds ratios (OR) was 1.27 (95% confidence interval (CI)=1.10-1.48, I(2)=75.5%) in the 12 cross-sectional studies and 1.62 (95% CI=0.74-3.55, I(2)=71.4%) in the 3 cohort studies; for long sleep durations (>8 to 10 h), the OR was 1.23 (95% CI=1.02-1.49, I(2)=75.8%) in the 11 cross-sectional studies and 1.62 (95% CI=0.86-3.04, I(2)=0.0%) in the 2 cohort studies. CONCLUSIONS: Short and long sleep durations are risky behaviors for increasing the risk of metabolic syndrome and thus have important public health implications, as sleep habits are amenable to behavioral interventions. The available data are sparse, and further studies, especially longitudinal studies, are needed to facilitate a better understanding of these associations.

AI snapshot

Written from the paper’s full text.

TL;DR

This meta-analysis of observational studies found that both short and long sleep durations were associated with higher metabolic syndrome risk in cross-sectional studies, with a U-shaped dose–response relationship. Cohort estimates were not statistically significant, and the authors call for more longitudinal data.

Key findings

  • In 12 cross-sectional studies (76,027 participants; 14,404 metabolic syndrome cases), short sleep (<5 to 6 h) had a pooled OR of 1.27 (95% CI=1.10–1.48, I²=75.5%); long sleep (>8 to 10 h) in 11 cross-sectional studies had an OR of 1.23 (95% CI=1.02–1.49, I²=75.8%).
  • In 3 cohort studies (2,055 participants; 283 incident cases), short sleep had an OR of 1.62 (95% CI=0.74–3.55, I²=71.4%); long sleep in 2 cohort studies had an OR of 1.62 (95% CI=0.86–3.04, I²=0.0%).
  • Dose–response analysis in 8 cross-sectional studies showed significant nonlinearity (P<0.001), with ORs versus 7 h/day of 1.33 (95% CI=1.07–1.65) for ≤5 h, 1.11 (95% CI=1.02–1.21) for 6 h, 1.26 (95% CI=1.07–1.49) for 9 h, and 1.38 (95% CI=1.10–1.74) for ≥9.5 h.
  • No publication bias was detected by Egger’s or Begg’s tests; sensitivity analyses in healthy populations weakened the short-sleep OR to 1.22 (95% CI=0.96–1.54) and the long-sleep OR to 1.14 (95% CI=0.98–1.32).

Methods

  • Systematic review and meta-analysis of observational studies; searched PubMed, Cochrane CENTRAL, EMBASE, and PsycINFO through 26 November 2012 without language restriction, identifying 12 cross-sectional and 3 cohort studies.
  • Extracted adjusted risk estimates and pooled ORs using random-effects models with 7 h/day as the reference; assessed heterogeneity with Q statistics/I² and publication bias with Egger’s and Begg’s tests; conducted subgroup analyses by study design, sleep measure, metabolic syndrome definition, gender, age, and geographic region.
  • Performed a two-stage random-effects dose–response meta-analysis using restricted cubic splines with three knots at the 10th, 50th, and 90th percentiles in 8 cross-sectional studies.

Limitations

  • Paper-stated: there was evidence of heterogeneity across studies, especially from heterogeneous sleep-measure methods, study quality, and variations in metabolic syndrome definitions; residual confounding cannot be fully excluded.
  • Paper-stated: the dose–response approach depends on means, medians, or midpoints of sleep-duration categories and is therefore slightly less accurate than individual patient data meta-analyses; available data are sparse, especially longitudinal studies.
  • Paper-stated and evident: cohort estimates were not statistically significant and were based on few studies/participants (3 cohort studies, 2,055 participants; only 2 for long sleep), and cross-sectional studies cannot establish temporality; the paper also notes possible recall bias from self-reported sleep duration.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/nutd.2013.8

Cites

58 of 58 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 3 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Sensitivity analysis excluding two studies in police officers yielded nearly identical summary ORs of 1.25 (95% CI 1.07-1.46; I2=78.6%) for short sleep and 1.22 (95% CI 1.22-1.48; I2=77.9%) for long sleep.

    “The sensitivity meta-analyses yielded nearly identical summary ORs of 1.25 (95% CI=1.07–1.46; I2=78.6%) for short sleep and 1.22 (95% CI=1.22–1.48; I2=77.9%) for long sleep.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Long sleep duration was associated with metabolic syndrome in cohort studies, with pooled OR 1.62 (95% CI 0.86-3.04, I2=0.0%) across 2 studies.

    “for long sleep durations (>8 to 10 h), the OR was 1.23 (95% CI=1.02–1.49, I2=75.8%) in the 11 cross-sectional studies and 1.62 (95% CI=0.86–3.04, I2=0.0%) in the 2 cohort studies.”
    • Also stated in: § Long duration of sleep · plain
      “The pooled OR between long sleep and metabolic syndrome was 1.23 (95% CI=1.02–1.49, I2=75.8%) in the 11 cross-sectional studies and 1.62 (95% CI=0.86–3.04, I2=0.0%) in the 2 cohort studies.”
    Quote in the paperNot a substantial claim
  • Findingown data

    No differences between men and women were found in subgroup analyses.

    “There were significant differences in the mean age, cohort-based group, definition of metabolic syndrome, quality of study and sleeping measure (P for heterogeneity <0.1). No significant group difference was found for gender or location.”
    • Also stated in: § Long duration of sleep · plain
      “There were significant differences in location, definition of metabolic syndrome, quality of study and sleeping measure (P for heterogeneity <0.1). No significant group difference was found for gender, age or cohort-based group.”
    • Also stated in: § Discussion · plain
      “There was some heterogeneity between studies, no publication bias and no differences between men and women.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Short sleep duration (<5 to 6 h) was associated with increased risk of metabolic syndrome in cross-sectional studies, with pooled OR 1.27 (95% CI 1.10-1.48, I2=75.5%) across 12 studies.

    “For short sleep durations (<5 to 6 h), the odds ratios (OR) was 1.27 (95% confidence interval (CI)=1.10–1.48, I2=75.5%) in the 12 cross-sectional studies and 1.62 (95% CI=0.74–3.55, I2=71.4%) in the 3 cohort studies”
    • Also stated in: § Short duration of sleep · plain
      “The pooled OR between short sleep and metabolic syndrome was 1.27 (95% CI=1.10–1.48, I2=75.5%) in the 12 cross-sectional studies and 1.62 (95% CI=0.74–3.55, I2=71.4%) in the 3 cohort studies (Figure 2).”
    Quote in the paperSubstantial claim
  • Findingown data

    Long sleep duration (>8 to 10 h) was associated with increased risk of metabolic syndrome in cross-sectional studies, with pooled OR 1.23 (95% CI 1.02-1.49, I2=75.8%) across 11 studies.

    “for long sleep durations (>8 to 10 h), the OR was 1.23 (95% CI=1.02–1.49, I2=75.8%) in the 11 cross-sectional studies and 1.62 (95% CI=0.86–3.04, I2=0.0%) in the 2 cohort studies.”
    • Also stated in: § Long duration of sleep · plain
      “The pooled OR between long sleep and metabolic syndrome was 1.23 (95% CI=1.02–1.49, I2=75.8%) in the 11 cross-sectional studies and 1.62 (95% CI=0.86–3.04, I2=0.0%) in the 2 cohort studies.”
    Quote in the paperSubstantial claim
  • May combine two claims. 14
  • Classified as probably not a substantial claim. 7

  • May combine two claims.

    Findingown data

    Short sleep duration was significantly associated with greater risk of metabolic syndrome in 4 of 12 cross-sectional studies and 2 of 3 cohort studies.

    “Short duration of sleep was significantly associated with a greater risk of developing metabolic syndrome in four of the twelve cross-sectional studies and two of the three cohort studies.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In cross-sectional studies, subgroup analyses for long sleep found significant differences in location, definition of metabolic syndrome, quality of study, and sleeping measure (P for heterogeneity <0.1).

    “There were significant differences in location, definition of metabolic syndrome, quality of study and sleeping measure (P for heterogeneity <0.1). No significant group difference was found for gender, age or cohort-based group.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The meta-analysis included 12 cross-sectional studies with 76,027 participants and 14,404 metabolic syndrome cases.

    “We identified 12 cross-sectional studies with 76 027 participants including 14 404 cases of metabolic syndrome, and 3 cohort studies with 2055 participants and 283 incident cases of metabolic syndrome.”
    • Also stated in: § Study characteristics · plain
      “The 12 cross-sectional17, 19, 20, 21, 22, 23, 33, 34, 35, 36 studies, with 76 027 participants, including 14 404 metabolic syndrome patients and the three cohort15, 18 studies, with 2055 participants, are represented in Table 1.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The dose-response meta-analysis of eight cross-sectional studies found a U-shaped association between sleep duration and metabolic syndrome risk, with increased risk at both shorter and longer sleep durations compared with 7 h/day.

    “Among the shorter and longer sleepers, the risk of metabolic syndrome might increase gradually compared with individuals who report sleeping 7 h per day.”
    • Also stated in: § Discussion · plain
      “Furthermore, compared with the 7-h sleep duration, U-shaped associations between sleep duration and the risk of metabolic syndrome were observed in a dose–response meta-analysis of eight cross-sectional studies.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The meta-analysis included 3 cohort studies with 2,055 participants and 283 incident metabolic syndrome cases.

    “We identified 12 cross-sectional studies with 76 027 participants including 14 404 cases of metabolic syndrome, and 3 cohort studies with 2055 participants and 283 incident cases of metabolic syndrome.”
    • Also stated in: § Study characteristics · plain
      “A total of 283 metabolic syndrome cases occurred during follow-up in the three cohort studies.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In cross-sectional studies, subgroup analyses for long sleep found no significant group difference for gender, age, or cohort-based group.

    “There were significant differences in location, definition of metabolic syndrome, quality of study and sleeping measure (P for heterogeneity <0.1). No significant group difference was found for gender, age or cohort-based group.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Long sleep duration was associated with greater risk of metabolic syndrome in 5 of 11 cross-sectional studies and none of 2 cohort studies.

    “Long duration of sleep was associated with a greater risk of developing metabolic syndrome in five of the eleven cross-sectional studies and none of the two cohort studies.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In cross-sectional studies, subgroup analyses for short sleep found significant differences in mean age, cohort-based group, definition of metabolic syndrome, quality of study, and sleeping measure (P for heterogeneity <0.1).

    “There were significant differences in the mean age, cohort-based group, definition of metabolic syndrome, quality of study and sleeping measure (P for heterogeneity <0.1). No significant group difference was found for gender or location.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Findingnone given

    The available data are sparse.

    “However, the available data are sparse, and further studies, especially longitudinal studies, are needed to enable more in-depth analyses, more precise and stable estimates of the association and a better understanding of the potential role of sleep duration in metabolic syndrome risk.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The adjusted risk estimates that reflected the most comprehensive control were extracted to avoid potential confounding.

    “The adjusted risk estimates that reflected the most comprehensive control were extracted to avoid potential confounding variables.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study quality was high in 10 of the 15 included studies (3 cohort and 12 cross-sectional).

    “The study quality was high in 10 of the 15 included studies (3 cohort and 12 cross-sectional studies).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Two reviewers independently extracted data from original reports.

    “Two reviewers (J-SY and C-WS) independently extracted the data from original reports.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    This study shows a significant increased risk of metabolic syndrome on either end of the distribution of sleep duration in cross-sectional studies, but not in cohort studies.

    “This study shows a significant increased risk of metabolic syndrome on either end of the distribution of sleep duration in the cross-sectional studies, but not in the cohort studies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The methodological quality of eligible non-randomized studies was assessed according to seven domains.

    “The methodological quality of the eligible non-randomized studies reviewed in meta-analyses was assessed according to the seven domains proposed as being fundamental to the methodological quality of the included studies (Supplementary Table 3).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [25] Panagioti M, Gooding PA, Tarrier N . A meta-analysis of the association between posttraumatic stress disorder and suicidality: the role of comorbid depression. Compr Psychiatry 2012; 53: 915–930. source

      Not checked in the free run.

    • cites [26] Sanderson S, Tatt ID, Higgins JP . Tools for assessing quality and susceptibility to bias in observational studies in epidemiology: a systematic review and annotated bibliography. Int J Epidemiol 2007; 36: 666–676. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    Longer sleepers show an increased risk for metabolic syndrome, confirming a U-shaped association in cross-sectional studies.

    “Longer sleepers also show an increased risk for metabolic syndrome, confirming the presence of a U-shaped association in the cross-sectional studies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The meta-analysis was planned, conducted, and reported according to MOOSE standards.

    “We planned, conducted and reported this systematic review according to widely accepted standards of quality for reporting meta-analyses of observational studies in epidemiology (Supplementary Table 1).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 2000; 283: 2008–2012. source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    To account for heterogeneity, random-effects models were used, and subgroup analyses using fixed-effects models did not significantly change results.

    “To account for this heterogeneity, we used random-effects models of the meta-analyses, and conducted subgroup analyses using fixed-effects models; however, the results were not significantly changed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Although the meta-analysis included only multivariable adjusted ORs, there is evidence of heterogeneity across studies in both study designs.

    “Although our meta-analysis included only multivariable adjusted ORs, there is evidence of heterogeneity across the studies in both study designs.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    The primary strength is that this is the first meta-analysis examining the relationship between sleep duration and metabolic syndrome based on a comprehensive literature search.

    “The primary strength is that this is the first meta-analysis that examines the relationship between sleep duration and metabolic syndrome based on a comprehensive literature search.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Short and long sleep durations are risky behaviors for increasing the risk of metabolic syndrome.

    “Therefore, short and long sleep durations are risky behaviors for increasing the risk of metabolic syndrome and thus have important public health implications, as sleep habits are amenable to behavioral interventions.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Sleep habits are amenable to behavioral interventions.

  • May combine two claims.

    Interpretationown data

    Both short sleepers and long sleepers are at risk of metabolic syndrome in cross-sectional studies, but not in cohort studies.

    “In this systemic review and meta-analysis of epidemiological studies of the association between sleep duration and metabolic syndrome, both short sleepers and long sleepers are at risk of metabolic syndrome in cross-sectional studies, but not in cohort studies; this is consistent with the results from an analysis using nonlinear dose–response method in the cross-sectional studies.”
    Quote in the paperSubstantial claim
21 of 21

  • The paper relies on this without support.

    Sleep habits are amenable to behavioral interventions.

    “as sleep habits are amenable to behavioral interventions”
1 of 1

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  • Included studies extend beyond the 2000s

    Minor

    The paper says all included studies were published in the 2000s, but its reference list includes an included study published in 2012.

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Authors
Ju, S.-Y., & Choi, W.-S.
Affiliations
  • The Catholic University of Korea Yeouido St. Mary's Hospital (KR)
  • The Catholic University of Korea Seoul St. Mary's Hospital (KR)
Corresponding author
Choi, W-S
ORCID
Ju, S-Y
Venue
Nutrition & Diabetes
Publisher
Springer Science and Business Media LLC
Published
2013-05-13
Volume
3
Issue
5
Pages
e65-e65
ISSN
2044-4052 (ISSN-L)
DOI
10.1038/nutd.2013.8
PMC
PMC3671750
OpenAlex
W2068207802
Semantic Scholar
b2258763ee24f2398ca9ce4dc3f0393a32711537
Cited by
130
References
58
Citations by year
2026: 3 · 2025: 10 · 2024: 4 · 2023: 7 · 2022: 14 · 2021: 14 · 2020: 10 · 2019: 7 · 2018: 12 · 2017: 13 · 2016: 13 · 2015: 19 · 2014: 2 · 2013: 1
FWCI
1.94
Type
journal article
Language
en
Open access
Licence
Locations
  • Nutrition and Diabetes (publishedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
Keywords
sleep duration, metabolic syndrome, short sleep duration, long sleep, sleep habits, risk factors, behavioral interventions

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