Fatty liver disease in the pediatric population: history, definitions, and challenges in nomenclature (NAFLD/MAFLD/MASLD)

This review focuses on the evolution in the nomenclature of fatty liver disease in the pediatric population, from the initial definition non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated fatty liver disease (MAFLD), and more recently to metabolic dysfunction-associated steatotic liver disease (MASLD). These changes in the nomenclature aim to more accurately reflect the relation between the disease and the underlying metabolic alterations, while also seeking to reduce the stigma associated with earlier definitions. Epidemiological data indicate an increase in the global burden of NAFLD in the pediatric population, with a prevalence of 5%-10%, more commonly affecting males. The condition is strongly associated with obesity, type 2 diabetes mellitus (T2DM), and genetic factors, including the PNPLA3 polymorphism. Prevalence rates are significantly higher in Latin America (24%-68%), which is linked to the growing epidemic of metabolic syndrome. In terms of pathophysiology, pediatric NAFLD differs from the adult form in the histological patterns and has a strong link to insulin resistance. Each definition of the disease has pros and cons. NAFLD is a simple definition but exclusionary, while MAFLD incorporates metabolic factors to better characterize the disease. The most recent term, MASLD, aims to reduce the stigma of this disease and emphasize the metabolic factor of this pathology. Various scientific societies consistently recommend lifestyle changes as the first-line treatment, although adherence to this intervention remains a challenge in the pediatric population. In addition, there is a strong consensus on the need for noninvasive tools and longitudinal studies to better understand this disease in children.