Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in the developed world, affecting 20 to 30% of Western adults. Nonalcoholic liver disease occurs with a range of severity from simple steatosis through nonalcoholic steatohepatitis (NASH) to fatty fibrosis and, ultimately, cirrhosis. The condition is a manifestation of the metabolic syndrome, strongly associated with obesity, insulin resistance, and dyslipidaemia. Dietary and genetic factors appear to determine susceptibility to the disease and its progression. In most patients, the condition is discovered incidentally when abnormal values of serum liver-related liver tests are reported. The diagnosis is usually one of exclusion. Liver biopsy is not always required but, in the absence of well-validated noninvasive biomarkers, remains the only way to detect steatohepatitis and accurately stage fibrosis of intermediate severity. However, biopsy is not practical in all cases and so a staged approach to patient assessment and risk stratification is advised. Treatment is directed at components of the metabolic syndrome: weight loss through diet and exercise has been shown to ameliorate disease. A range of novel pharmacological drug treatments are under evaluation.