Metabolic dysfunction-associated fatty liver disease (MAFLD) is a new concept proposed in 2020. Unlike non-alcoholic fatter liver disease (NAFLD), the diagnosis of MAFLD requires the presence any of the following 3 metabolic risks, including overweight/obesity, presence of diabetes mellitus, and evidence of metabolic dysregulation. However, there are patients that have hepatic steatosis but no metabolic risk, who thus do not meet the diagnostic criteria of MAFLD. Besides, there are patients with both MAFLD and other liver diseases. The clinical features and the management of these patients remain unclear. Thus, further histopathological and clinical study is required to elucidate and compare the characteristics of MAFLD and NAFLD. Here, in this single-center, prospective clinical study, investigators are planning to establish a long-term follow-up cohort of patients with either MAFLD or NAFLD. In order to understand the risk of developing liver-related complications and important extra-hepatic outcomes (e.g. cardiovascular disease), and also to better elucidate the risk of disease progression in lean NAFLD individuals without any metabolic dysregulation and MAFLD individuals with dual or multiple causes. Ultimately, investigators aim to improve the diagnosis of MAFLD and improve patients' outcomes.