Obesity and Air Pollution: Global Risk Factors for Pediatric Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is becoming as an important health problem in the pediatric age group. In addition to the well-documented role of obesity on the fatty changes in liver, there is a growing body of evidence about the role of environmental factors, such as smoking and air pollution, in NAFLD. Given that excess body fat and exposure to air pollutants is accompanied by systemic low-grade inflammation, oxidative stress, as well as alterations in insulin/insulin-like growth factor and insulin resistance, all of which are etiological factors related to NAFLD, an escalating trend in the incidence of pediatric NAFLD can be expected in the near future. This review focuses on the current knowledge regarding the epidemiology, diagnosis and pathogenesis of pediatric NAFLD. The review also highlights the importance of studying the underlying mechanisms of pediatric NAFLD and the need for broadening efforts in prevention and control of the main risk factors. The two main universal risk factors for NAFLD, obesity and air pollution, have broad adverse health effects, and reducing their prevalence will help abate the serious health problems associated with pediatric NAFLD.