Comparison of clinical characteristics between lean and obese nonalcoholic fatty liver disease in the northeast Chinese population

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is seen commonly in patients with obesity, but there are many non-obese people who also have NAFLD, which we call lean NAFLD. The objective of this study is to compare the characters of lean and obese NAFLD individuals aimed to better understand the pathogenesis of NAFLD. MATERIAL AND METHODS: A total of 496 NAFLD cases (history of alcohol consumption, medication used within the last 3 months, hepatitis virus infection, autoimmune or hereditary liver disease were excluded), divided into an obese (body mass index (BMI) ≥ 25 kg/m(2)) NAFLD group (n = 395) and lean (BMI < 25 kg/m(2)) NAFLD group (n = 101), were investigated. Gender, age, alanine aminotransferase, triglycerides, cholesterol, and the blood glucose were compared between the two groups. RESULTS: A male-dominated discrepancy of gender distribution was more evident in obese NAFLD group. Elevated alanine amonotransferase was more common in the obese NAFLD group. 50–59 years was the peak age of both lean and obese NAFLD groups. Normal triglycerides (TG) patients were more common in the lean NAFLD group, while the proportion of elevated TG patients was higher in the obese NAFLD group. No statistically significant difference in the proportion of elevated cholesterol patients was found between the two groups. In the lean NAFLD group, the proportion of females was higher in the normal fasting glucose group. CONCLUSIONS: Sexual dimorphism exists in lean NAFLD patients, but this trend was most pronounced during the age range 40–49 years and disappeared after entering the 50–59-year-old age range. In lean NAFLD patients, normal levels of TG and blood glucose were more common, and occurrence of non-alcoholic steatohepatitis was less common than among obese NAFLD.