The aim of the present study was to reveal the metabolic disorders most commonly associated with nonalcoholic fatty liver disease (NAFLD). Triglyceride (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), blood glucose (BG) and hemoglobin A1c (HbA1c) were analyzed. NAFLD was diagnosed using abdominal ultrasound (US), and TG, HDL, LDL, BG and HbA1c were immediately collected on the same day and subjected to multivariate regression analysis. Stepwise analysis was performed to select the variables that were closely associated with NAFLD. The patients who were positive for the hepatitis B antigen and hepatitis C antibody were excluded from the study. Additionally, the patients who were prescribed prednisolone or methotrexate were excluded from the study as these agents may cause NAFLD or liver toxicity. The study included 168 and 125 patients with and without NAFLD, respectively. TG, BG and HbA1c were strongly correlated with NAFLD. Among these parameters, TG was the strongest predictor of NAFLD (χ=9.89, P=0.0017). TG was the parameter that was most strongly associated with NAFLD. In conclusion, elevated TG was a marker of NAFLD.

In the present study, the threshold values of laboratory data for the diagnosis of non-alcoholic fatty liver disease (NAFLD) were investigated. The study enrolled patients who had undergone abdominal ultrasound (US) between April 2013 and August 2013, and for whom laboratory data were available on the same day. NAFLD was diagnosed following observations of a bright liver or hepatorenal echo contrast on the abdominal US scans. Patients were excluded from the study if they had liver diseases or had been prescribed prednisolone or methotrexate. Receiver operating characteristic curves, the Wilcoxon signed-rank test and Fisher’s exact probability test were used for data analysis. In total, 80 NAFLD and 94 non-NAFLD patients were enrolled in the study. The threshold levels of alanine aminotransferase (ALT) and triglyceride (TG) for the diagnosis of NAFLD were 19.0 IU/l and 101 mg/dl, respectively. Patients were divided into two groups according to the levels of ALT and TG. Those with ALT levels of >19 IU/l and TG levels of >101 mg/dl were defined as the positive group, while the remaining patients were classified as the negative group. The specificity and positive predictive value using the combined threshold levels of ALT >19 IU/l and TG >101 mg/dl were 80.9 and 75.0%, respectively. Therefore, the results indicated that ALT levels of >19 IU/l or TG levels of >101 mg/dl were useful markers for the screening of NAFLD. However, NAFLD was more strongly suspected in patients with ALT levels of >19 IU/l and TG levels of >101 mg/dl.