Alternation of Non-alcoholic Fatty Liver Disease (NAFLD) and Cardiovascular Risks After Liftestyle Modification: A Ultrasound Attenuation Imaging-Based Study

Overview

The prevalence of obesity has significantly increased over the last few decades. The excessive fat accumulation in undesired areas in obese patients may lead to various complications, such as cardiovascular diseases and Non-alcoholic fatty liver disease (NAFLD) defined by intrahepatic triglycerides (IHTG) content higher than 5.5%. In Hong Kong, the incidence rate of NAFLD is as high as approximately 13.5%, while 60.5% of obese subjects suffer from NAFLD. NAFLD is found to be a well-established risk factor for chronic kidney disease, type 2 diabetes, and cardiovascular disease. Moreover, obesity is a strong independent risk factor for development of atherosclerosis. It also plays important role in pathogenesis of dyslipidaemia, insulin resistance, hypertension. Both NAFLD and cardiovascular risks can be reversed. Lifestyle modification program(LMP) including diet control and routine exercise has been widely recommended to patients with mild to moderate obesity. It is vital to have a non-invasive, non-ionizing, low cost, accessible or widely available and yet accurate assessment tool to diagnose NAFLD and some cardiovascular risk parameters and serially monitor changes to assess the efficacy of LMP. Ultrasound meets these requirements. To the best of our knowledge there has been no prior study similar to this one. In this study, we aim to assess and validate the diagnostic accuracy of a novel ultrasound attenuation imaging method for NAFLD, and to evaluate the effectiveness of LMP in reversal of NAFLD and reduction of cardiovascular risks in moderate obesity. A total of forty moderate obese patients with NAFLD will be recruited in this study, divided into lifestyle modification program group(n=20) and usual care group(n=20). All subjects will undergo dietary assessment based on 3-day diet record and power of food scale. Demographic data will be recorded, consisted of age, weight, height, waist circumference, BMI, and so on. Ultrasound attenuation imaging (ATI) will be performed to measure tissue attenuation coefficient so as to evaluate liver steatosis and liver fibrosis stage. Meanwhile, magnetic resonance imaging (MRI) will be carried out, which include cardiovascular risks measurement, liver proton density fat fraction (PDFF), volume quantification of abdominal white adipose tissue, liver inflammation and fibrosis assessment. Biochemistry tests will be conducted as supplementary for assessment of NAFLD and cardiovascular risks, comprising liver function test, lipid, fasting glucose, etc.