title: Impact of Obstructive Sleep Apnea on Liver Fat Accumulation According to Sex and Visceral Obesity.
abstract: BACKGROUND
  Associations between obstructive sleep apnea (OSA) and liver fat accumulation have been frequently investigated because both morbidities are common. Visceral fat was reported to be closely related to OSA and liver fat accumulation. Recently, sex differences in the association between OSA and mortality have gained much attention.
  
  
  OBJECTIVE
  To investigate the associations among OSA, liver fat accumulation as determined by computed tomography, and visceral fat area and their sex differences.
  
  
  METHODS
  Studied were 188 males and 62 females who consecutively underwent polysomnography and computed tomography.
  
  
  RESULTS
  Although the apnea-hypopnea index was positively correlated with liver fat accumulation in the total males, none of the OSA-related factors was independently associated with liver fat accumulation in either the total male or female participants in the multivariate analyses. When performing subanalyses using a specific definition for Japanese of obesity or visceral obesity (body mass index (BMI) ≥25 kg/m2 or visceral fat area ≥100 cm2), in only males without visceral obesity, percent sleep time with oxygen saturation <90%, in addition to BMI, insulin resistance, and serum triglyceride values, was independently correlated with liver fat accumulation (R2 = 15.1%, P<0.001). In males, percent sleep time of oxygen saturation <90% was also a determining factor for alanine aminotransferase values regardless of visceral fat area. In contrast, OSA was not associated with liver fat accumulation or alanine aminotransferase values in females whether or not visceral obesity was absent.
  
  
  CONCLUSIONS
  Sex differences in the visceral fat-dependent impact of OSA on liver fat accumulation existed. Although the mechanisms are not known and ethnic differences may exist in addition to the specific criteria of visceral obesity in Japan, the treatment of male patients with OSA might be favorable from the viewpoint of preventing liver fat accumulation and liver dysfunction even in patients without obvious visceral fat accumulation.
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Toyama
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Tanizawa
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Respiratory Medicine, Otsu Red Cross Hospital, Shiga, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Chihara
authors.affiliation: Department of Respiratory Medicine, Kansai Electric Power Hospital, Osaka, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Harada
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Murase
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Azuma
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamada
authors.affiliation: Department of Clinical Laboratory, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Hitomi
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Handa
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Oga
authors.affiliation: Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Chiba
authors.affiliation: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
authors.affiliation: Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000473:pathology*; D008099:Liver / Q000473:pathology*; D008297:Male; D015999:Multivariate Analysis; D017286:Polysomnography; D012044:Regression Analysis; D012189:Retrospective Studies; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000473:pathology*; D014057:Tomography, X-Ray Computed