for Health Care Providers
Nonalcoholic Fatty Liver Disease, Obesity and Viral Hepatitis
Nonalcoholic fatty liver disease (NAFLD) is the presence of hepatic steatosis (fat) in the absence of significant alcohol use as a cause. NAFLD is associated with obesity, diabetes mellitus, dyslipidemia (high or low HDL, or high triglyceride levels), and metabolic syndrome. Estimates of the prevalence of NAFLD vary widely but the median estimate is a prevalence of 20% in the general population, although some studies have found prevalence of 40-50%. The prevalence of NAFLD is expected to rise as obesity has reached epidemic levels around the world. Other risk factors for NAFLD may be older age, male gender, Hispanic ethnicity, hypothyroidism, hypopituitarism, hypogonadism, sleep apnea, and polycystic ovary syndrome.
Obesity is also associated with insulin resistance and other metabolic changes, which can directly cause liver damage. In addition to steatosis itself causing hepatic inflammation and fibrosis, obesity and fatty liver exacerbate the liver injury in patients with other chronic liver diseases such as hepatitis C infection. It is theorized that hepatocyte regeneration, which can occur in the setting of viral hepatitis, may be impaired in patients with fat deposition in hepatocytes. Clinically, it has been demonstrated that, when patients with hepatitis C who were also obese were compared with patients with hepatitis C who were not obese, the obese patients had increased levels of fibrosis. It also has been demonstrated that obese patients with hepatitis C have a decreased response to HCV treatment compared with non-obese patients. Furthermore, weight loss has been shown to provide benefit to patients with viral hepatitis. In nearly 1,000 subjects with hepatitis C cirrhosis, weight loss was associated with a decrease in inflammation on serial biopsies over 3.5 years and improved response to peginterferon plus ribavirin therapy.
As part of the general management of chronic viral hepatitis, providers are strongly encouraged to counsel patients who are overweight to lose weight--in order to reduce their rate of fibrosis progression and to reduce the multitude of other health risks associated with obesity. Providers can also refer their patients to additional behavioral health and weight loss resources in the VA like the MOVE! Program.
The Diagnosis and Management of Non-Alcoholic Fatty Liver Disease: Practice Guideline by the American Association for the Study of Liver Diseases, American College of Gastroenterology, and the American Gastroenterological Association
Chalasani, N, Younossi, Z, Lavine, J, et al; Hepatology, Vol. 55, No. 6, 2012, 2005-2023