Relationship between liver fat content and liver enzymes in individuals with various statuses of glucose metabolism

Abstract

To study the relationship between liver fat content (LFC) and liver enzymes in individuals with various statuses of glucose metabolism. A total of 109 subjects including with impaired glucose regulation (IGR) (n = 31), newly diagnosed type 2 diabetes (NT2DM) (n = 31) and normal glucose tolerance (NGT) (n = 47) were recruited. The level of LFC was measured by (1)H magnetic resonance spectroscopy ((1)H-MRS) to study the relationship between liver fat content (LFC) and alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP) and γ-glutamyltransferase (GGT). The receiver operating characteristic curve (ROC) was employed to obtain the optimal cut-off point of ALT to predict the occurrence of nonalcoholic fatty liver disease (NAFLD). (1) The levels of LFC were progressively raised in NGT, IGR and NT2DM groups respectively [3.83 (2.35 - 7.59)%, 12.82 (8.10 - 21.37)% and 21.99 (11.89 - 34.43)%, P < 0.01]; (2) the subjects were divided into four subgroups by the method of LFC quartile. And quartile subgroups Q1-4 were associated with the increase of LFC. Waist, BMI, systolic blood pressure, triglyceride, total cholesterol, fasting plasma glucose, OGTT 2 h postprandial glucose and HOMA-IR had a rising trend from Q2. But HDL-C showed a declining trend from Q2; (3) ALT and GGT significantly increased from Q3 (P < 0.01) while AST and AKP significantly increased in Q4 (P < 0.01); (4) adjusted by gender, age and body mass index (BMI), LFC was positively correlated with AST (r = 0.329, P < 0.05), ALT (r = 0.454) and GGT (r = 0.378) (All P < 0.01). But it was negatively correlated with AST/ALT (r = -0.364, P < 0.01); (5) the analysis of stepwise regression demonstrated that LFC was a predictor of ALT, AST, GGT and AST/ALT; (6) ALT had a ROC(AUC) of 0.813 (male) and 0.769 (female) (All P < 0.01). The optimal cut-off point of 23.5 U/L (male) and 17.5 U/L (female) might predict the occurrence of NAFLD. Liver enzymes are correlated with LFC even in normal range. The optimal cut-off point of 23.5 U/L (male) and 17.5 U/L (female) might predict the occurrence of NAFLD. The current used ALT upper limit could underestimate the NAFLD.