As American waistlines continue to expand, a lesser-known obesity-related disease is quickly becoming more common. In fact, in its most serious form, the disease is estimated to become the leading cause for liver transplants by 2020, outpacing even hepatitis C. It's known as nonalcoholic fatty liver disease (NAFLD), an umbrella term for a range of liver conditions that, as the name implies, affects people who drink little to no alcohol yet have more than 5 percent of their liver made up of fat cells. According to the Mayo Clinic, NAFLD affects an estimated 80 million to 100 million Americans.
The more progressive — and therefore more worrisome — form of the disease is known as NASH, or nonalcoholic steatohepatitis. By this stage the disease has progressed to liver inflammation, which can lead to cirrhosis, liver failure and liver cancer — similar to the kind of damage occurring with heavy alcohol use. Dr. Rohit Loomba, chairman of the American Liver Foundation's National Medical Advisory Committee, estimates that about 30 million Americans have NASH.
Like many adverse medical conditions, NAFLD — and especially the more progressive form of the disease — is linked to obesity. Dr. Loomba says that 90 percent of the patients diagnosed with NASH are either overweight or obese. "Obesity and diabetes rates are very high in the U.S. and are also increasing worldwide," he says. "So when we look at the rising rates of NASH in people who don't drink and don't have hepatitis C yet are still developing cirrhosis of the liver, we know something is damaging the liver and we're not containing it."
Perhaps the most alarming aspect of NAFLD, says researchers, is that in its mildest form it typically causes no signs or symptoms, isn't readily picked up in a routine physical, and currently there are no drugs on the market to treat it (although several are in the pipeline).
Dr. Jay Horton, director of the Center for Human Nutrition at UT Southwestern Medical Center, says an individual will typically discover he or she has fatty liver disease if they have a liver function test that comes back abnormal or if they have a scan of their abdomen for some other reason, such as gallstones. "Even though they're finding out about it almost by accident, it's actually very easy to detect excess liver fat with an imaging modality, such as an MRI, CT scan or ultrasound," he says.
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