摘要目的 观察不同糖代谢人群中肝酶与肝脏脂肪含量(LFC)的关系.方法 109例受试者分为糖调节异常(IGR)31例,新诊断2型糖尿病(NT2DM)31例,正常糖耐量(NGT)47例,采用质子磁共振波谱分析(1H-MRS)定量测定LFC,分析LFC与丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、碱性磷酸酶(AKP)、γ-谷氨酰转肽酶(GGT)的关系.利用受试者工作曲线(ROC)获得ALT诊断非酒精性脂肪肝病(NAFLD)的最佳临界值.结果 (1)LFC在NGT、IGR、NT2DM组中分别为3.83(2.35～7.59)%、12.82(8.10～21.37)%、21.99(11.89～34.43)%,随着糖代谢异常程度增加依次增高(P＜0.01);(2)根据LFC四分位数分组,分为Q1～4组.随着LFC增加,腰围、体质指数(BMI)、收缩压、甘油三酯、总胆固醇、空腹血糖、OGTT 2 h血糖、HOMA胰岛素抵抗指数(HOMA-IR)从Q2起呈现增高趋势,HDL-C从Q2起呈现降低趋势,组间比较差异有统计学意义;(3)随着LFC增加,ALT、AST、AKP、GGT均数虽尚在正常范围,但ALT、GGT在Q3时,AST、AKP在Q4时出现增高(P＜0.01);(4)偏相关分析发现,校正了性别、年龄、BMI后,LFC与AST(r=0.329,P＜0.05),ALT(r=0.454)、GGT(r=0.378)(均P＜0.01)呈正相关,与AST/ALT(r=-0.364,P＜0.01)呈负相关;(5)多元回归分析显示LFC是ALT、AST、GGT、AST/ALT独立影响因子;(6)ALT检测NAFLD,ROC曲线下面积为0.813(男),0.769(女)(均P＜0.01),ALT最佳临界值23.5 U/L(男),17.5 U/L(女).结论 肝酶在正常的范围内即与LFC相关,以目前ALT正常切点来诊断NAFLD,低估了NAFLD的实际患病率.

abstractsObjective To study the relationship between liver fat content (LFC) and liver enzymes in individuals with various statuses of glucose metabolism. Methods 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 1H magnetic resonance spectroscopy (1H-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). Results (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 singnificantly 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 ROCAuc 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. Conclusions 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.