Nonalcoholic fatty liver disease (NAFLD) has been associated with relative skeletal muscle mass in several cross-sectional studies. We explored the effects of relative skeletal muscle mass and changes in relative muscle mass over time on the development of incident NAFLD or the resolution of baseline NAFLD in a large, longitudinal, population-based 7-year cohort study. We included 12,624 subjects without baseline NAFLD and 2943 subjects with baseline NAFLD who underwent health check-up examinations. A total of 10,534 subjects without baseline NAFLD and 2631 subjects with baseline NAFLD were included in analysis of changes in relative skeletal muscle mass over a year. Subjects were defined as having NAFLD by the hepatic steatosis index, a previously validated NAFLD prediction model. Relative skeletal muscle mass was presented using the skeletal muscle mass index (SMI), a measure of body weight-adjusted appendicular skeletal muscle mass, which was estimated by bioelectrical impedance analysis. Of the 12,624 subjects without baseline NAFLD, 1864 (14.8%) developed NAFLD during the 7-year follow-up period. Using Cox proportional hazard analysis, compared with the lowest sex-specific SMI tertile at baseline, the highest tertile was inversely associated with incident NAFLD (adjusted hazard ratio [AHR] = 0.44, 95% confidence interval [CI] = 0.38-0.51) and positively associated with the resolution of baseline NAFLD (AHR = 2.09, 95% CI = 1.02-4.28). Furthermore, compared with the lowest tertile of change in SMI over a year, the highest tertile exhibited a significant beneficial association with incident NAFLD (AHR = 0.69, 95% CI = 0.59-0.82) and resolution of baseline NAFLD (AHR = 4.17, 95% CI = 1.90-6.17) even after adjustment for baseline SMI. Conclusion: Increases in relative skeletal muscle mass over time may lead to benefits either in the development of NAFLD or the resolution of existing NAFLD.

The effects of exendin-4 on Sirt1 expression as a mechanism of reducing fatty liver have not been previously reported. Therefore, we investigated whether the beneficial effects of exendin-4 treatment on fatty liver are mediated via Sirt1 in high-fat (HF) diet-induced obese C57BL/6J mice and related cell culture models. Exendin-4 treatment decreased body weight, serum free fatty acid (FA), and triglyceride levels in HF-induced obese C57BL/6J mice. Histological analysis showed that exendin-4 reversed HF-induced hepatic accumulation of lipids and inflammation. Exendin-4 treatment increased mRNA and protein expression of Sirt1 and its downstream factor, AMPK, in vivo and also induced genes associated with FA oxidation and glucose metabolism. In addition, a significant increase in the hepatic expression of Lkb1 and Nampt mRNA was observed in exendin-4-treated groups. We also observed increased expression of phospho-Foxo1 and GLUT2, which are involved in hepatic glucose metabolism. In HepG2 and Huh7 cells, mRNA and protein expressions of GLP-1R were increased by exendin-4 treatment in a dose-dependent manner. Exendin-4 enhanced protein expression of Sirt1 and phospho-AMPKα in HepG2 cells treated with 0.4 mM palmitic acid. We also found that Sirt1 was an upstream regulator of AMPK in hepatocytes. A novel finding of this study was the observation that expression of GLP-1R is proportional to exendin-4 concentration and exendin-4 could attenuate fatty liver through activation of Sirt1.

BackgroundNon-alcoholic fatty liver disease (NAFLD) is a prevalent and rapidly increasing disease worldwide; however, no widely accepted screening models to assess the risk of NAFLD are available. Therefore, we aimed to develop and validate a self-assessment score for NAFLD in the general population using two independent cohorts.MethodsThe development cohort comprised 15676 subjects (8313 males and 7363 females) who visited the National Health Insurance Service Ilsan Hospital in Korea in 2008–2010. Anthropometric, clinical, and laboratory data were examined during regular health check-ups and fatty liver diagnosed by abdominal ultrasound. Logistic regression analysis was conducted to determine predictors of prevalent NAFLD and to derive risk scores/models. We validated our models and compared them with other existing methods using an external cohort (N = 66868).ResultsThe simple self-assessment score consists of age, sex, waist circumference, body mass index, history of diabetes and dyslipidemia, alcohol intake, physical activity and menopause status, which are independently associated with NAFLD, and has a value of 0–15. A cut-off point of ≥8 defined 58% of males and 36% of females as being at high-risk of NAFLD, and yielded a sensitivity of 80% in men (77% in women), a specificity of 67% (81%), a positive predictive value of 72% (63%), a negative predictive value of 76% (89%) and an AUC of 0.82 (0.88). Comparable results were obtained using the validation dataset. The comprehensive NAFLD score, which includes additional laboratory parameters, has enhanced discrimination ability, with an AUC of 0.86 for males and 0.91 for females. Both simple and comprehensive NAFLD scores were significantly increased in subjects with higher fatty liver grades or severity of liver conditions (e.g., simple steatosis, steatohepatitis).ConclusionsThe new non–laboratory-based self-assessment score may be useful for identifying individuals at high-risk of NAFLD. Further studies are warranted to evaluate the utility and feasibility of the scores in various settings.

OBJECTIVETo evaluate whether there is a difference in the association between nonalcoholic fatty liver disease (NAFLD) and incident diabetes based on the presence of impaired fasting glucose.RESEARCH DESIGN AND METHODSA total of 7,849 individuals (5,409 men and 2,440 women) without diabetes, who underwent comprehensive health check-ups annually for 5 years, were categorized into four groups by the presence of impaired fasting glucose and NAFLD at baseline. The association between NAFLD and incident diabetes was evaluated separately in groups with normal and impaired fasting glucose.RESULTSFor 4 years, the incidence of diabetes in the NAFLD group was 9.9% compared with 3.7% in the non-NAFLD group, with multivariable-adjusted hazard ratio of 1.33 (95% CI 1.07–1.66). However, this higher risk for diabetes only existed in the impaired fasting glucose group.CONCLUSIONSOur study suggests that NAFLD has an independent and additive effect on the development of diabetes under conditions of impaired insulin secretion.

A cross-sectional analysis was conducted in healthy, nondiabetic Korean adults to assess the prevalence of nonalcoholic fatty liver disease (NAFLD), to compare the prevalence of NAFLD across different glycemic ranges as assessed by glycosylated hemoglobin (HbA1c), and to examine the impact of NAFLD on insulin resistance in relation to HbA1c levels. METHODS:After rigorous exclusion criteria, the fi nal number of subjects who participated in a comprehensive health status checkup program was 99,969. All subjects were classifi ed into four categories with respect to HbA1c level ( ≤ 4.9, 5.0 -5.4, 5.5 -5.9, and 6.0 -6.4 % ). We estimated the odds ratio (OR) for prevalence of NAFLD according to the categorized level of HbA1C and evaluated the association of NAFLD with the homeostatic model assessment of insulin resistance (HOMA-IR) in relation to the HbA1c level. RESULTS:Twenty-eight percent ( n = 28,130, 40.2 % of the men, 10.3 % of the women) of the study subjects had NAFLD. Men had a 5.83-fold (95 % confi dence interval 5.63 -6.05) increased risk for having NAFLD than did women. The risk for NAFLD increased with increasing level of HbA1c (OR 1.44, 2.62, and 7.18) when compared with the lowest quartile (HbA1C ≤ 4.9 % ). HOMA-IR increased in the NAFLD subjects as the level of HbA1c increased. The magnitude of association of HOMA-IR with HbA1c level was greater in NAFLD subjects than in non-NAFLD subjects ( P < 0.001 for interaction). These associations were consistent even after adjustment for body mass index and other metabolic components.CONCLUSIONS: NAFLD had an association with HbA1c level and insulin resistance in nondiabetic individuals, and these associations were independent of obesity and other metabolic components.

OBJECTIVEWe aimed to evaluate the effects of carnitine-orotate complex in patients with nonalcoholic fatty liver disease (NAFLD) and diabetes. RESEARCH DESIGN AND METHODSEight hospitals in Korea participated in this randomized, controlled, double-blind trial of patients with diabetes and NAFLD. Seventy-eight patients were randomly assigned in a 1:1 ratio to receive carnitine-orotate complex (824 mg, three times daily) or matching placebo. The primary study outcome was decline in alanine aminotransferase (ALT) to the normal range. Secondary study outcomes were change in ALT, radiological hepatic steatosis, parameters for anthropometry, liver function, lipid profiles, and glycemic control. Hepatic steatosis was assessed using Hounsfield units on noncontrast computed tomography (CT) imaging with hepatic attenuation. RESULTSAfter 12 weeks of treatment, compared with placebo group, carnitine-orotate complex-treated participants had a significantly higher rate of normalization of serum ALT level (17.9% vs. 89.7%, P < 0.001). On hepatic CT analysis, participants treated with carnitine-orotate complex showed an increased liver attenuation index (0.74 6 8.05 vs. 6.21 6 8.96, P < 0.008). A significant decrease in HbA 1c was observed in the carnitine-orotate complex group (20.33 6 0.82% [23.6 6 9.0 mmol/mol], P = 0.007), but no significant change was seen in the placebo group. CONCLUSIONSTreatment with carnitine-orotate complex improves serum ALT and may improve hepatic steatosis as assessed by CT in patients with diabetes and NAFLD. Further studies using more advanced magnetic resonance imaging and liver histology as an end point are needed to assess its efficacy in NAFLD.Ectopic fat accumulation in a visceral organ is associated with insulin resistance (1). As an example of such ectopic fat accumulation, nonalcoholic fatty liver disease (NAFLD) is now recognized as the hepatic component of metabolic syndrome and is even reportedly associated with insulin resistance independent of obesity and other metabolic components. Therefore, NAFLD can be a major determinant of insulin

Context:Traditional lipid measures are known to be associated with incident type 2 diabetes.Objective: Our objective was to assess the independent association between lipid profiles and the development of type 2 diabetes in nondiabetic Korean subjects over a 4-yr period. Design and Methods:A total of 5577 Koreans without diabetes who underwent consecutive comprehensive health check-ups annually for 5 yr were enrolled. We measured concentrations of total cholesterol (TC), triglyceride (TG), apolipoprotein B (apoB), apolipoprotein A-I, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) and calculated lipid ratios. The association between incident type 2 diabetes and the initial values for lipid ratios and other lipoprotein components was examined.Results: Over the course of 4 yr, 330 subjects (5.9%) developed type 2 diabetes. TC, LDL-C, TG, non-HDL, apoB, apoB to apolipoprotein A-I ratio, TC to HDL ratio, TG to HDL ratio, LDL to HDL ratio and apoB to HDL ratio were associated with incident type 2 diabetes in multivariate analysis after adjustment for age and gender. Of these, the ratio of TC to HDL and apoB to HDL showed a significant association with increased risk of type 2 diabetes, compared with other lipoprotein parameters: odds ratio (1.340, 95% confidence interval 1.166 -1.538; and 1.338, 95% confidence interval 1.162-1.540), respectively. The odds ratio for the development of type 2 diabetes increased significantly as the tertiles of the baseline ratio of TC to HDL and apoB to HDL increased from the first to the third tertile.Conclusions: This study suggests that lipid and lipoprotein profiles can be independently associated with later development of type 2 diabetes in nondiabetic Korean adults in a longitudinal analysis. (J Clin Endocrinol Metab 96: E2050 -E2054, 2011)

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