title: Prevalence and Severity of Nonalcoholic Fatty Liver Disease in Non-Obese Patients: A Population Study Using Proton-Magnetic Resonance Spectroscopy.
abstract: OBJECTIVE
  Some studies suggest that non-obese patients with nonalcoholic fatty liver disease (NAFLD) may have more severe disease. We aim to study the epidemiology and severity of non-obese NAFLD.
  
  
  METHODS
  A total of 911 community subjects were randomly recruited from the census database of the Hong Kong Government. Intrahepatic triglycerides (IHTG) and liver fibrosis were assessed by proton-magnetic resonance spectroscopy and transient elastography, respectively. The Asian body mass index cutoff of 25 kg/m(2) was used to define non-obese NAFLD.
  
  
  RESULTS
  The prevalence of NAFLD was 19.3% in non-obese subjects and 60.5% in obese subjects (P<0.001). Compared with obese NAFLD patients, non-obese NAFLD patients had similar IHTG content (median 9.8% vs. 9.9%; P=0.100) but lower cytokeratin-18 fragments (149 vs. 182 IU/l; P=0.019) and liver stiffness (4.6 vs. 5.6 kPa; P<0.001). The G allele at the patatin-like phospholipase domain-containing protein 3 gene (PNPLA3 rs738409) was more common in non-obese than obese NAFLD patients (78.4% vs. 59.8%; P=0.001). Obesity, high hemoglobin A1c, insulin resistance, hyperferritinemia, and the PNPLA3 G allele were independent factors associated with NAFLD in non-obese subjects. Even among non-obese subjects with normoglycemia, those with NAFLD were more insulin resistant (mean homeostasis model assessment of insulin resistance: 2.0±1.0 vs. 1.1±1.1; P<0.001).
  
  
  CONCLUSIONS
  One-fifth of the general non-obese Chinese population has NAFLD. Non-obese patients with NAFLD do not have a higher risk of steatohepatitis or advanced fibrosis. Patients with risk factors of advanced fibrosis such as metabolic syndrome and PNPLA3 G allele carriage should be assessed for severe NAFLD.
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Jeremy Lok
authors.initials: JL
authors.lastname: Wei
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Jonathan Chung-Fai
authors.initials: JC
authors.lastname: Leung
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Thomson Chi-Wang
authors.initials: TC
authors.lastname: Loong
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Institute of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.|State Key Laboratory of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Grace Lai-Hung
authors.initials: GL
authors.lastname: Wong
authors.affiliation: Department of Clinical Oncology, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: David Ka-Wai
authors.initials: DK
authors.lastname: Yeung
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Centre for Nutritional Studies, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Ruth Suk-Mei
authors.initials: RS
authors.lastname: Chan
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Institute of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.|State Key Laboratory of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Henry Lik-Yuen
authors.initials: HL
authors.lastname: Chan
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Institute of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.|State Key Laboratory of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Angel Mei-Ling
authors.initials: AM
authors.lastname: Chim
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Centre for Nutritional Studies, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Jean
authors.initials: J
authors.lastname: Woo
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Winnie Chiu-Wing
authors.initials: WC
authors.lastname: Chu
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.|Institute of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.|State Key Laboratory of Digestive Disease, Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Vincent Wai-Sun
authors.initials: VW
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008099:Liver / Q000473:pathology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000175:diagnosis / Q000453:epidemiology*; D009765:Obesity; D011159:Population Surveillance; D015995:Prevalence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult