Abstract
Non-alcoholic fatty liver disease determined by MRI and its association with metabolic variables in non-diabetic subjects Background: Non-alcoholic fatty liver disease (NAFLD) is defined as the presence of hepatic steatosis (liver fat accumulation higher than 5% of liver weight) in the absence of other causes. Liver biopsy is recognized as a gold standard for diagnosis, but it is limited by the risks of serious complications. Besides that, the increasing prevalence of NASH led to improved imaging methods, such as Magnetic Resonance Imaging (MRI), that enable quantitative assessment of steatosis by quantifying the hepatic fat fraction (HFF), even with steatosis levels as low as 5.56%. Objective: The aim of this study was to evaluate the metabolic profile of patients without T2DM according to hepatic steatosis measured by MRI. Methods: This was cross-sectional study conducted in an Endocrinology Unity in Minas Gerais, Brazil. The study complied with the WMA Declaration of Helsinki and was approved by the Ethical Committee on Human Subject Research from the Faculty Patos de Minas. We recruited non-diabetic subjects aged above 20 years with hepatic steatosis detected by liver sonography. Exclusion criteria were alcohol consumption of more than 20 grams/day for female and 30 grams/day for male, ferritin serum levels above 1000 mg/dL, positive serology for hepatitis B or C and intake of medications known to produce hepatic steatosis. Included subjects underwent HFF quantification by MRI, and the degree of liver fatty infiltration was estimated by using chemical shift imaging. The following biochemical variables were assessed: fasting glucose and HbA1c, HOMA-IR, lipids, AST, ALT and GGT. Analysis: we grouped individuals according to the quartile of HFF and compared clinical and biochemical variables between the groups. Results: A total of 30 subjects (18 male and 12 females) were included. All subjects were overweight (10% overweight and 90% obese); 7 (23.3%) had 3 criteria and 16 (53.3%) had two criteria for MS. The only variable assessed herein that was different between males and females was HDL-c (40.5 vs 50.5 mg/dL, respectively, p=0.0255). ALT serum levels were significantly higher in subjects in the fourth quartile of HFF, when compared to those in the third quartile (76 vs 47 UI/L, respectively, p=0.037). The other clinical of biochemical variables assessed did not differ between the quartiles of HFF. Conclusion: our preliminary findings indicate that the biochemical variables related to metabolic homeostasis are poor predictors of the degree of liver fat in overweight non-diabetic subjects. Although screening for NAFLD is still a matter of debate, our results suggest that future discussions about this should take into account that excess body weight per se, independently from biochemical abnormalities, should be considered in the recommendations for screening non-diabetic subjects.