Fatty liver disease is the name given to a condition in which the liver’s healthy, reddish-brown tissue becomes streaked with fatty deposits. Fatty liver disease can be categorized as Alcoholic Fatty Liver Disease (AFLSD) or Non-Alcoholic Fatty Liver Disease (NAFLD), based on how the condition was acquired. Both AFLD and NAFLD encompass a range of conditions from simple steatosis (fatty infiltration of the liver tissue) to cirrhosis (an irreversible and potentially fatal build up of scar tissue in the liver).
What are the Risk Factors for Fatty Liver Disease?
AFLD– Chronic alcoholism or abuse of other potentially toxic substances damages the liver and can lead to three liver conditions of increasing severity: alcoholic fatty liver (sometimes called simple steatosis), alcoholic hepatitis, and alcohol-related cirrhosis. Alcoholic fatty liver is the least serious of these conditions and can be reversed with recovery from alcoholism.
Non alcoholic fatty liver disease is found in people of all ages, but it is seen most frequently in middle-aged people. It is more common in women than in men and is seen more frequently in overweight individuals. It is not associated with alcohol use. Paradoxically, people who have had operations, including gastric bypass weight loss surgeries, during which large sections of their small intestine were removed, may develop NAFLD as a result of rapid weight loss.
NAFLD– Follows the same basic progression as AFLD, but it is found in people who use little or no alcohol. The increasing incidence of obesity, diabetes, and prediabetic conditions such as insulin resistance and metabolic syndrome in industrialized countries has led to an increase in non-alcoholic fatty liver disease. The exact prevalence of NAFLD is unknown, but it has become increasingly common due to the increase of obesity.
Although obesity is a known risk factor for NAFLD, it tends to occur most frequently in people who carry their excess weight around their waist. Medical investigators believe this may be because abdominal obesity is a risk factor for other conditions like insulin resistance, type 2 diabetes, and metabolic syndrome, which also promote the development of NAFLS. Elevated cholesterol and triglycerides are often seen in people with this condition. Some health experts estimate that it may affect up to one-third of all American adults.
Symptoms and Diagnosis of NAFLD
The liver has tremendous reserve capacity so it can function within normal limits, even when fatty deposits infiltrate it. Consequently, early-stage NAFLD rarely causes any symptoms, or if symptoms do occur, they are tend to be vague and nonspecific. For example, patients may report fatigue, feeling mildly unwell, or discomfort in the upper right quadrant of their abdomen. Patients typically learn they have early stage NAFLD only when a blood test performed to evaluate an unrelated condition reveals abnormal liver function.
One paper published in 2005 estimated that 20% of all American adults have early stage NAFLD and that 10% to 15% of these people develop non-alcoholic steatohepetitis (NASH). Approximately 20% of patients with NASH are at risk for developing cirrhosis and for subsequently dying from end-stage liver disease.1
Progression and Treatment of NAFLD
NAFLD can remain stable in some people for years. If left untreated, it may progress, just as AFLD can, to non-alcoholic steatohepetitis, characterized by generalized inflammation of the liver tissue and some fibrous tissue development, and eventually transition into full-blown cirrhosis in which fibrous tissue replaces much of the functional liver tissue. However, what triggers the progression from early NAFLD to these more serious liver diseases is unclear. Medical researchers familiar with NAFLD believe that some type of secondary assault to the liver may cause the disease to progress.
Initial treatment of NAFLD includes weight loss, exercise, improved diabetes control, and the use of cholesterol-lowering medications. If your physician tells you that you have NAFLD, it is important that you follow the treatment plan, including weight loss, to prevent further liver damage and death.
Researchers suspect that there may be a genetic component to NAFLD. They are conducting studies to determine if genes play a role in the development of NAFLD or if genes influence how fast and far the disease progresses. They hope their research will lead to better treatments for this condition.
Major Risk Factors for NAFLD
Overweight and Obesity. Your risk increases with every pound of excess weight. More than 70 percent of people with nonalcoholic steatohepatitis (NASH) are obese.
Type 2 Diabetes. Insulin resistance and high blood sugar can damage many organs in your body, including your liver. As many as 75% of people diagnosed with NASH also have diabetes.
Hyperlipidemia. High blood cholesterol and triglyceride levels are found in 80% of people with NASH.
Intestinal Bypass Surgeries. These types of surgeries, including gastric bypass, which lead to rapid weight loss, can, paradoxically, trigger NAFLD.
Medications. The side effects of some medications include liver damage and may result in NAFLD.
Other Liver Diseases. Other disease and conditions which affect the liver such as glycogen storage disease and Wilson’s disease, which results in high levels of copper being stored in the liver, can lead to NAFLD.
1Neuschwander-Tetri, B A. Nonalcoholic Steatohepatitis and the Metabolic Syndrome, Am J Medical Sciences. 2005; 330(6):326-335,