title: The absence of obstructive sleep apnea may protect against non-alcoholic fatty liver in patients undergoing bariatric surgery.
abstract: BACKGROUND
  Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide and its progressive form, steatohepatitis, will be the leading indication for liver transplant by 2020. While risk factors for steatohepatitis have been identified, little work has been performed to identify factors protective against NAFLD development.
  
  
  OBJECTIVE
  This study sought to identify factors predictive of normal liver histology in a bariatric cohort.
  
  
  METHODS
  Patients undergoing weight loss surgery with liver biopsies at the time of surgery were included. Patients with other causes of chronic liver disease were excluded.
  
  
  RESULTS
  One hundred fifty-nine patients were included. Forty-nine patients had normal liver histology and 110 patients had NAFLD. Several previously identified factors associated with normal liver histology were found. Black race was the strongest predictor of the absence of NAFLD with an odds ratio (OR) of 6.8, 95% confidence interval (CI) 2.4-18.9. Low HOMA-IR was also associated with normal histology (OR 1.4, 95% CI 1.03-1.9). In contrast, low HDL was associated with a decreased chance of normal histology (OR 0.38, 95% CI 0.05-0.83). Interestingly, a novel protective factor, the absence of obstructive sleep apnea (OSA) was strongly associated with normal histology (OR 5.6, 95% CI 2.0-16.1). In multivariate regression controlling for BMI, black race, absence of OSA, low HOMA-IR and low ALT independently predicted normal liver histology with an area under the ROC curve of 0.85.
  
  
  CONCLUSIONS
  Our study confirmed several factors associated with normal liver histology, including black race and identified a novel factor, absence of OSA. Further evaluation of these factors will allow for improved understanding of the pathogenesis of NAFLD.
authors: Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
authors: Kathleen E
authors: KE
authors: Corey
authors: Joseph
authors: J
authors: Misdraji
authors: Hui
authors: H
authors: Zheng
authors: Kyle M
authors: KM
authors: Malecki
authors: Jacob
authors: J
authors: Kneeman
authors: Louis
authors: L
authors: Gelrud
authors: Raymond T
authors: RT
authors: Chung
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000378:metabolism; D050110:Bariatric Surgery; D001706:Biopsy; D044383:Black People; D005234:Fatty Liver / Q000175:diagnosis / Q000208:ethnology / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D012372:ROC Curve; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D016896:Treatment Outcome; D015431:Weight Loss; D044465:White People
chemical_list: D008075:Lipoproteins, HDL; D000410:Alanine Transaminase
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