Non alcoholic fatty liver disease Foreword

Non alcoholic fatty liver disease (NAFLD) is highly prevalent in Western countries as well as in some Latin American countries such as Brazil, Chile and Mexico. In fact, it has been estimated that the prevalence of NAFLD ranged from 17 to 33% in the general population of Western countries. Besides, it has been identified some ethnic differences in the epidemiology of NAFLD. For example, the prevalence of steatosis in United States, assessed by magnetic resonance spectroscopy, was highest in Hispanics (45%), followed by whites (33%), and African Americans (24%). Interestingly, the genetic variants contributing to differences in hepatic fat content have been identified in a recent study carried-out in a genome-wide association scan of nonsynonymous sequence variations. This investigation found an allele in PNPLA3 (rs738409[G], encoding I148M) that was strongly associated with increased hepatic fat levels and with hepatic inflammation. The allele was most common in Hispanics, the group most susceptible to NAFLD. This information clearly emphasizes the importance of NAFLD in this population. On the other hand, currently NAFLD is a recognized as a condition that ranges from simple steatosis to steatohepatitis (NASH). NASH is a more severe form of NAFLD in which fatty infiltration of the liver is accompanied by necroinflammatory activity, and is now recognized as one of the most common cause of chronic liver disease. The occurrence of NASH is clinically important as approximately 15– 25% of these patients will progress to cirrhosis. In this supplement the epidemiology, pathophysiology, diagnosis, treatment as well as other comorbidities of NAFLD are carefully reviewed by some experimented researches in this field. I am delighted to present the edition of the Symposium on Non-Alcoholic Fatty Liver Disease held at Medica Sur Clinic & Foundation in Mexico City in October 3, 2008. I hope you will enjoy this thorough update of current knowledge in the field.