Systematic Review Article: Etiology of Non-Alcoholic Fatty Liver Disease (NAFLD)

Non-Alcoholic Fatty Liver Disease (NAFLD) is now the most common cause of chronic liver disease worldwide, affecting approximately 25% of the adult population. NAFLD encompasses a spectrum of conditions ranging from simple hepatic steatosis to the more severe Non-Alcoholic Steatohepatitis (NASH), which can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. The etiology of NAFLD is multifactorial and involves complex interactions between genetic, metabolic, and environmental factors. Central to the pathogenesis of NAFLD is insulin resistance, which promotes fat accumulation in the liver through increased de novo lipogenesis and impaired lipid oxidation. Other contributing factors include dyslipidemia, oxidative stress, chronic inflammation, and dysregulation of the gut-liver axis. This systematic review aims to provide a comprehensive synthesis of the current understanding of the etiology of NAFLD, including key mechanisms and risk factors that drive disease development and progression. The review also highlights emerging research on the role of genetic predisposition and the gut microbiome in NAFLD.