Epidemiology of Non-alcoholic Fatty Liver Disease in North America.

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the most common cause of chronic liver disease worldwide. This is primarily driven by the global epidemic of obesity and diabetes as well as the aging of the general population. Most of the epidemiology data of NAFLD for North America are published from studies originating in the United States (U.S.). The overall prevalence of NAFLD in the U.S. is estimated to be 24%. Hispanic Americans have a higher prevalence of NAFLD, whereas African Americans have a lower prevalence of NAFLD. The exact contributions of genetic and environmental factors on these differences in the prevalence rates have not been determined. From the spectrum of NAFLD, patients with non-alcoholic steatohepatitis (NASH) are at the highest risk of progression to cirrhosis and hepatocellular carcinoma (HCC). The most recent data regarding the progression of NASH suggest a complex pattern of progression and regression of fibrosis. Factors influencing the progression and regression of NASH have not been fully described. More research is needed to better understand NAFLD in Mexico and Canada.