Context: In the last few years, several data have accumulated suggesting that obesity may be associated with liver disease and disease progression. Accordingly, the worldwide epidemic of obesity is likely to become a relevant source of morbidity and mortality in the general population.
Evidence acquisition: We reviewed the literature on two main issues: 1) the evidence that obesity carries out an increased risk of liver disease, both in the general population and in selected cohorts; and 2) the evidence that obesity is a risk factor for nonalcoholic fatty liver disease and its progression in a series observed in liver units.
Evidence synthesis: The presence of obesity increases the risk of elevated liver enzymes by a factor of two to three, whereas the risk of steatosis at ultrasonography is increased by a factor of 3 in the presence of overweight and peaks at a factor of approximately 15 in the presence of obesity. Both cirrhosis (cryptogenic cirrhosis) and hepatocellular carcinoma are also associated with obesity in the general population. In patients with nonalcoholic fatty liver disease observed in liver units, obesity and weight gain are systematically associated with advanced fibrosis and fibrosis progression.
Conclusion: Liver disease of metabolic origin, associated with obesity, is now recognized as the most prevalent liver disease in Western countries. Strategies are needed to approach obesity-associated liver disease by behavior programs, motivating people to adopt a healthier lifestyle. Such programs should be coupled with public policies at a societal level to obtain the maximum effects in lifestyle changes.