Prevalence and Severity of Nonalcoholic Fatty Liver Disease in Non-Obese Patients: A Population Study Using Proton-Magnetic Resonance Spectroscopy

• Published in: The American journal of gastroenterology Vol. 110; no. 9; pp. 1306 - 1314
• Main Authors: Wei, Jeremy Lok, Leung, Jonathan Chung-Fai, Loong, Thomson Chi-Wang, Wong, Grace Lai-Hung, Yeung, David Ka-Wai, Chan, Ruth Suk-Mei, Chan, Henry Lik-Yuen, Chim, Angel Mei-Ling, Woo, Jean, Chu, Winnie Chiu-Wing, Wong, Vincent Wai-Sun
• Format: Journal Article
• Language: English
• Published: United States Wolters Kluwer Health Medical Research, Lippincott Williams & Wilkins 01.09.2015
• Subjects: Adolescent; Adult; Body Mass Index; Cross-Sectional Studies; Female; Follow-Up Studies; Gastroenterology; Hong Kong - epidemiology; Humans; Liver - pathology; Magnetic Resonance Spectroscopy - methods; Male; Middle Aged; Non-alcoholic Fatty Liver Disease - diagnosis; Non-alcoholic Fatty Liver Disease - epidemiology; Obesity; Population Surveillance; Prevalence; Retrospective Studies; Severity of Illness Index; Young Adult; Hong Kong
• ISSN: 0002-9270; 1572-0241
• DOI: 10.1038/ajg.2015.235

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. 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. 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). 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.