title: Cholecystectomy is independently associated with nonalcoholic fatty liver disease in an Asian population.
abstract: OBJECTIVE
  To investigate the relationship between gallstone disease and nonalcoholic fatty liver disease (NAFLD) in a large Asian population.
  
  
  METHODS
  A cross-sectional study including 17612 subjects recruited from general health check-ups at the Seoul National University Hospital, Healthcare System Gangnam Center between January 2010 and December 2010 was conducted. NAFLD and gallstone disease were diagnosed based on typical ultrasonographic findings. Subjects who were positive for hepatitis B or C, or who had a history of heavy alcohol consumption (> 30 g/d for men and > 20 g/d for women) or another type of hepatitis were excluded. Gallstone disease was defined as either the presence of gallstones or previous cholecystectomy, and these two entities (gallstones and cholecystectomy) were analyzed separately. Clinical parameters including body mass index, waist circumference, hypertension, diabetes, smoking status, and regular physical activity were reviewed. Laboratory parameters, including serum levels of gamma-glutamyl transpeptidase, alanine aminotransferase, aspartate aminotransferase, fasting glucose, fasting insulin, total cholesterol, triglycerides, and high-density lipoprotein, were also reviewed.
  
  
  RESULTS
  The mean age of the subjects was 48.5 ± 11.3 years, and 49.3% were male. Approximately 30.3% and 6.1% of the subjects had NAFLD and gallstone disease, respectively. The prevalence of gallstone disease (8.3% vs 5.1%, P < 0.001), including both the presence of gallstones (5.5% vs 3.4%, P < 0.001) and a history of cholecystectomy (2.8% vs 1.7%, P < 0.001), was significantly increased in the NAFLD group. In the same manner, the prevalence of NAFLD increased with the presence of gallstone disease (41.3% vs 29.6%, P < 0.001). Multivariate regression analysis showed that cholecystectomy was associated with NAFLD (OR = 1.35, 95%CI: 1.03-1.77, P = 0.028). However, gallstones were not associated with NAFLD (OR = 1.15, 95%CI: 0.95-1.39, P = 0.153). The independent association between cholecystectomy and NAFLD was still significant after additional adjustment for insulin resistance (OR = 1.45, 95%CI: 1.01-2.08, P = 0.045).
  
  
  CONCLUSIONS
  This study shows that cholecystectomy, but not gallstones, is independently associated with NAFLD after adjustment for metabolic risk factors. These data suggest that cholecystectomy may be an independent risk factor for NAFLD.
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Min-Sun
authors.initials: MS
authors.lastname: Kwak
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Donghee
authors.initials: D
authors.lastname: Kim
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Goh Eun
authors.initials: GE
authors.lastname: Chung
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Kim
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Yoon Jun
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Min-Sun Kwak, Donghee Kim, Goh Eun Chung, Department of Internal Medicine, Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea.
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D000328:Adult; D044466:Asian People; D016009:Chi-Square Distribution; D002763:Cholecystectomy / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D005260:Female; D042882:Gallstones / Q000175:diagnosis / Q000208:ethnology / Q000601:surgery*; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D065626:Non-alcoholic Fatty Liver Disease / Q000175:diagnosis / Q000208:ethnology*; D016017:Odds Ratio; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors
keywords: Cholelithiasis; Fatty liver; Gallbladder; Gallbladder removal; Hepatic steatosis