Fatty liver disease and its determinants in an American Indian Population: the Strong Heart Study

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Abstract: Fatty liver disease (FLD), hepatic steatosis and fibrosis, often leads to cirrhosis and cancer. Among American Indians (AI), chronic liver disease is the fifth leading cause of death (CDC). However, few data exist on age-adjusted prevalence rates of chronic liver disease, and none on hepatic steatosis and fibrosis in AI. Risk factors include obesity, insulin resistance, alcohol consumption and viral hepatitis, but there are also few data available on the individual and combined influence of each of these factors on the development of fatty liver and its progression to fibrosis. The Strong Heart Study (SHS) is the largest multicenter, prospective, epidemiologic study in American Indians, and has shown that AI have higher rates of obesity, insulin resistance, type 2 diabetes mellitus (T2D), and CVD than other groups in the United States. Although the presence of viral hepatitis is relatively low (<1%) prior exams show that >65% of SHS participants have elevated aminotransferase levels indicating liver injury; there is a wide range of alcohol consumption (with a majority reporting none [59%] or binge drinking [33%]). Given the high prevalence of known metabolic risk factors, the wide range of alcohol consumption and the availability of longitudinal data, the SHS of AI represents an excellent cohort with which to ask questions on the prevalence, cross-sectional associations and prospective determinants for hepatic steatosis and fibrosis, and could yield unique and valuable information on the links between insulin resistance, alcohol consumption and FLD. This study will use advanced magnetic resonance imaging (MRI) of the liver to non-invasively assess hepatic steatosis by MRI-derived proton density fat fraction (MRI-PDFF) and hepatic fibrosis by MR elastography-derived stiffness (MRE-stiffness) in a population-based sample of AI participants of the SHS. We propose to identify cross-sectional associations and longitudinal determinants of hepatic steatosis and fibrosis in AI from the SHS. We anticipate that we will gain an understanding of the longitudinal determinants explaining the increased rate of chronic liver disease in AI and identify important targets of intervention and prevention of FLD in populations with high rates of metabolic disease.