Evidence-Based Medicine
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World J Gastroenterol. Dec 21, 2014; 20(47): 17932-17940
Published online Dec 21, 2014. doi: 10.3748/wjg.v20.i47.17932
Lean-non-alcoholic fatty liver disease increases risk for metabolic disorders in a normal weight Chinese population
Ren-Nan Feng, Shan-Shan Du, Cheng Wang, Yan-Chuan Li, Li-Yan Liu, Fu-Chuan Guo, Chang-Hao Sun
Ren-Nan Feng, Shan-Shan Du, Yan-Chuan Li, Li-Yan Liu, Fu-Chuan Guo, Chang-Hao Sun, Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, Harbin 150081, Heilongjiang Province, China
Cheng Wang, Department of Environmental Hygiene, School of Public Health, Harbin Medical University, Harbin 150081, Heilongjiang Province, China
Author contributions: Feng RN, Du SS and Wang C contributed equally to this work; Feng RN and Sun CH designed the research; Wang C, Li YC and Guo FC performed the research; Feng RN, Liu LY and Du SS analyzed the data; Feng RN, Du SS, Liu LY and Wang C wrote the manuscript; Feng RN provided financial support for this work; all the authors were involved in revising the manuscript.
Supported by National Natural Science Fund of China, No. 81130049, No. 81202184; and 12th China Five-Year Scientific and Technical Plan, No. 2012BAI02B02
Correspondence to: Chang-Hao Sun, PhD, Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, No. 157 Baojian Street, Nangang District, Harbin 150081, Heilongjiang Province, China. changhao2002sun@gmail.com
Telephone: +86-451-87502881 Fax: +86-451-87502885
Received: April 5, 2014
Revised: June 12, 2014
Accepted: July 11, 2014
Published online: December 21, 2014
Processing time: 259 Days and 3.7 Hours
Abstract

AIM: To study the prevalence and clinical biochemical, blood cell and metabolic features of lean-non-alcoholic fatty liver disease (lean-NAFLD) and its association with other diseases.

METHODS: Demographic, biochemical and blood examinations were conducted in all the subjects in this study. We classified the subjects into four groups according to their weight and NAFLD status: lean-control, lean-NAFLD [body mass index (BMI) < 24 kg/m2], overweight-obese control and overweight-obese NAFLD. One-way analysis of variance (ANOVA) was used to compare the means of continuous variables (age, BMI, blood pressure, glucose, lipid, insulin, liver enzymes and blood cell counts) and the χ2 test was used to compare the differences in frequency of categorical variables (sex, education, physical activity, smoking, alcohol consumption and prevalence of hypertension, hyperlipidemia, diabetes, metabolic syndrome central obesity and obesity). Both univariate and multivariate logistic regression models were adopted to calculate odds ratios (ORs) and predict hyperlipidemia, hypertension, diabetes and metabolic syndrome when we respectively set all controls, lean-control and overweight-obese-control as references. In multivariate logistic regression models, we adjusted potential confounding factors, including age, sex, smoking, alcohol consumption and physical activity.

RESULTS: The prevalence of NAFLD was very high in China. NAFLD patients were older, had a higher BMI, waist circumference, blood pressure, fasting blood glucose, insulin, blood lipid, liver enzymes and uric acid than the controls. Although lean-NAFLD patients had lower BMI and waist circumstance, they had significantly higher visceral adiposity index than overweight-obese controls. Lean-NAFLD patients had comparable triglyceride, cholesterin and low-density lipoprotein cholesterin to overweight-obese NAFLD patients. In blood cell examination, both lean and overweight-obese NAFLD was companied by higher white blood cell count, red blood cell count, hemoglobin and hematocrit value. All NAFLD patients were at risk of hyperlipidemia, hypertension, diabetes and metabolic syndrome (MetS). Lean-NAFLD was more strongly associated with diabetes (OR = 2.47, 95%CI: 1.14-5.35), hypertension (OR = 1.72, 95%CI: 1.00-2.96) and MetS (OR = 3.19, 95%CI: 1.17-4.05) than overweight-obese-NAFLD (only OR for MetS was meaningful: OR = 1.89, 95%CI: 1.29-2.77). NAFLD patients were more likely to have central obesity (OR = 1.97, 95%CI: 1.38-2.80), especially in lean groups (OR = 2.17, 95%CI: 1.17-4.05).

CONCLUSION: Lean-NAFLD has unique results in demographic, biochemical and blood examinations, and adds significant risk for diabetes, hypertension and MetS in lean individuals.

Keywords: Lean-non-alcoholic fatty liver disease; Metabolic disorder; Diabetes; Risk; Chinese

Core tip: Obesity is an important risk factor for non-alcoholic fatty liver disease (NAFLD). NAFLD can also occur in lean subjects. Chinese people have lower body mass index than Americans and Europeans, but a similar prevalence of NAFLD. There might be different metabolic characters in Chinese population. We conducted this study to characterize metabolic features of lean-NAFLD and identify its association with metabolic disorders.