Nonalcoholic Fatty Liver Disease

Pouneh S. Mofrad, MD, Arun J. Sanyal, MD


April 16, 2003

In This Article


The prevalence of NAFLD in the general population ranges from 13% to 15%. These data have been obtained from a number of studies that have used varying criteria for the diagnosis of NAFLD. Studies that have used histologic characterization of the condition have all focused on specific patient populations within a hospital environment and are therefore potentially subject to selection and ascertainment bias.[4,5,6] However, population-based studies have used sonographic methods to make a presumptive diagnosis of NAFLD.[7,8,9,10,11] The latter studies are unable to distinguish between a fatty liver and steatohepatitis. Even more important, sonography cannot effectively distinguish between a fatty liver and other medical disorders of the liver.

Perhaps the studies least subject to selection bias are those of air crash victims who have undergone autopsies. Despite the heterogeneity of study methodologies, the overall prevalence of NAFLD in all investigations is similar, and ranges between 13% and 18%. Studies of liver biopsies of unselected autopsies or living donors for liver transplant indicate that the prevalence of steatohepatitis ranges from 2% to 4%.[12,13] This condition can affect any age group, including about 2.6% of children and up to 52.8% of obese children. NAFLD was originally believed to occur primarily in middle-aged obese women; however, more recent studies have shown that it occurs with equal frequency in men.[14]