title: Nocturnal intermittent hypoxia and metabolic syndrome; the effect of being overweight: the CIRCS study.
abstract: OBJECTIVE
  We investigated whether nocturnal intermittent hypoxia, a surrogate marker for obstructive sleep apnea, is associated with metabolic syndrome and its components among Japanese.
  
  
  METHODS
  We examined 1,710 male and 2,896 female community-dwelling Japanese aged 40 to 69, who participated in annual cardiovascular examinations and investigations of sleep. Nocturnal intermittent hypoxia was estimated based on a 3% oxygen desaturation index measured with pulse-oximetry during sleep. No, mild and moderate-to-severe nocturnal intermittent hypoxia were defined by <5, 5 to <15 and >or=15 events/hour, respectively. Metabolic syndrome was defined by modified criteria of the Adult Treatment Panel III guidelines.
  
  
  RESULTS
  Compared with no nocturnal intermittent hypoxia, the multivariable odds ratio of metabolic syndrome was 1.9 (95% confidence interval: 1.6-2.4) for mild and 3.2 (2.2-4.7) for moderate-to-severe nocturnal intermittent hypoxia among men; 2.6 (2.1-3.4) and 5.8 (3.4-9.8) among women, respectively. When stratified by overweight status (body mass index >or=25 kg/m(2)), the multivariable odds ratio of two or more metabolic risk factors (other than overweight) associated with moderate-to-severe nocturnal intermittent hypoxia was 1.9 (1.2-3.1) among non-overweight subjects and 1.4 (0.9-2.1) among overweight subjects (p for interaction=0.002).
  
  
  CONCLUSIONS
  Nocturnal intermittent hypoxia was associated with the accumulation of metabolic risk factors, especially among non-overweight individuals.
authors.affiliation: Public Health, Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Muraki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tanigawa
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yamagishi
authors.forename: Susumu
authors.initials: S
authors.lastname: Sakurai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ohira
authors.forename: Hironori
authors.initials: H
authors.lastname: Imano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kiyama
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kitamura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimamoto
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Konishi
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Iso
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology*; D008875:Middle Aged; D050177:Overweight / Q000150:complications*; D010100:Oxygen / Q000378:metabolism*; D011446:Prospective Studies; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000209:etiology*
chemical_list: D010100:Oxygen