title: Sleep Duration and Metabolic Syndrome. An Updated Dose-Risk Metaanalysis.
abstract: BACKGROUND
  Several studies have reported that both short and long sleep durations are associated with the metabolic syndrome, but whether a dose-response relationship exists is unclear.
  
  
  OBJECTIVE
  We performed a metaanalysis to study the magnitude of the association between the different durations of sleep and metabolic syndrome.
  
  
  METHODS
  We searched in the databases of PubMed, Web of Science, and Ovid (all Journals@Ovid) from inception to October 4, 2014 for cross-sectional studies where an association between metabolic syndrome and sleep duration was analyzed.
  
  
  RESULTS
  Eighteen studies with 75,657 participants were included. Daily sleep duration of 7 to 8 hours was used as the reference group. The odds ratio (OR) of having metabolic syndrome for short (<7 h) sleep was 1.23 (95% CI, 1.11-1.37; P < 0.001; I(2), 71%). The ORs for less than 5 hours, 5 to 6 hours, and 6 to 7 hours of sleep were 1.51 (95% CI, 1.10-2.08; P = 0.01), 1.28 (95% CI, 1.11-1.48; P < 0.001), and 1.16 (95% CI, 1.02-1.31; P = 0.02), respectively. The coefficient of sleep duration on log of ORs was -0.06 ± 0.02 (P = 0.02). The OR for long sleep duration was 1.13 (95% CI, 0.97-1.32; P = 0.10; I(2), 89%).
  
  
  CONCLUSIONS
  A dose-response relationship exists between short sleep duration and metabolic syndrome. Those who report a sleep duration of less than 5 hours have a 1.5 higher odds of having metabolic syndrome. Our study does not support the notion that long sleep is associated with metabolic syndrome.
authors.affiliation: 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; and.|2 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of South Carolina School of Medicine, Columbia, South Carolina.
authors.forename: Imran H
authors.initials: IH
authors.lastname: Iftikhar
authors.affiliation: 2 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of South Carolina School of Medicine, Columbia, South Carolina.
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Donley
authors.affiliation: 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; and.
authors.forename: Jesse
authors.initials: J
authors.lastname: Mindel
authors.affiliation: 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; and.
authors.forename: Adam
authors.initials: A
authors.lastname: Pleister
authors.affiliation: 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; and.
authors.forename: Sheryll
authors.initials: S
authors.lastname: Soriano
authors.affiliation: 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; and.
authors.forename: Ulysses J
authors.initials: UJ
authors.lastname: Magalang
mesh_terms: D015982:Bias; D003430:Cross-Sectional Studies; D006801:Humans; D024821:Metabolic Syndrome / Q000503:physiopathology*; D016017:Odds Ratio; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000378:metabolism*; D013997:Time Factors
keywords: metaanalysis; metabolic syndrome; sleep duration