Heavy drinking is often the cause of liver failure. But much of the increase in serious liver disease these days is found among those who rarely or never drink.
Nonalcoholic fatty liver disease, or NAFLD, is caused by a build-up of fat in the liver; it can lead to cirrhosis, late-stage scarring or liver failure, just as alcoholism can. If you’re overweight, obese, suffer from sleep apnoea or have Type 2 diabetes along with several other conditions, you are at increased risk of NAFLD. But it’s unclear what causes the disease.
“Patients usually come to the clinic because their liver blood tests are elevated or fatty liver has shown up” on imaging scans, said Rohit Loomba, a professor at the University of California at San Diego School of Medicine who is an expert on the disease. But all other possible causes of liver disease have to be ruled out before a diagnosis of NAFLD is made.
Your liver is your body’s largest internal organ, about the size of a football and located in the upper right portion of your abdomen, above your stomach. It processes everything you eat and drink, and it removes toxic substances from the body.
NAFLD causes a build-up of too much fat in liver cells; over time, this can cause the liver to swell and severely damage the organ. According to the American Liver Foundation, about 25 per cent of the US population has the disease. Loomba says it may be even higher, with as many as 100 million people affected. Yet most people have no idea, and have no symptoms until it is well advanced.
As obesity rises, says Rohit Satoskar, medical director of liver transplantation at MedStar Georgetown University Medical Centre Transplant Institute, so does the incidence of NAFLD.
According to Loomba, the disease is expected to affect more than 40 per cent of the adult US population by 2030.
About a fifth of those diagnosed with NAFLD will eventually develop the most serious, progressive form of the disease (called nonalcoholic steatohepatitis, or NASH), which can cause cirrhosis and liver failure and is now one of the leading reasons for liver transplantation. Loomba says there are approximately 6,000 liver transplants a year in this country, and as many as 2,000 of them are related to NAFLD or a cirrhosis related to it.
People with this most severe form generally show few symptoms until very late in the disease’s progression, when fatigue, weakness, abdominal pain, weight loss, jaundice and mental confusion can appear.
Ben Goodman, who lives in Washington, is only 25 years old, but he may be at risk of getting the fatty liver disease. When he was a teenager, his father, who never drank alcohol, died of liver disease. His father’s father also died of liver disease. Given that background, Goodman’s doctor advised him when he was 15 to get a liver biopsy despite his apparent good health. That biopsy showed elevated levels of liver enzymes, a condition that can precede NAFLD.
Goodman says he was shocked when he got the results and has been determined to stay as healthy as he can in an effort to keep the disease at bay.
Jay H. Hoofnagle, director of the liver disease research branch at the National Institute of Diabetes, Digestive and Kidney Diseases, believes that while obesity appears to be a risk factor, there is probably a genetic component that makes obesity more harmful to some people’s livers than to others. He said Asians, Hispanics and Native Americans appear to be more prone to developing the more severe form of the disease, whites less so and African Americans the least. (Goodman is white.)
Loomba says there are no accurate tests to tell whether a case of NAFLD will develop into NASH. And because the disease is mostly asymptomatic for decades, many people get treatment only after beginning to feel unwell.
The only therapies that can stave off or reverse liver damage caused by early-stage NAFLD are weight loss, eating a healthful diet and getting exercise. Although the disease is not caused by alcohol consumption, drinking does stress the liver, and doctors often recommend that those with NAFLD avoid alcohol, along with drugs that can stress the liver. It is also important to keep cholesterol and diabetes under control.
“We have to deal with the underlying problems, which are lack of physical exercise and poor eating habits,” says Hoofnagle.
Satoskar said the biggest problem is that the disease is “underrecognised, even among primary-care doctors.” Yet screening the population isn’t realistic, he adds, because the only way to diagnose NASH is with a liver biopsy. But a biopsy is an invasive procedure “and usually only considered if someone is at high risk”, as was the case with Goodman.
Goodman, who is 5-foot-6 and weighs 75 kilograms, makes sure to exercise at least three times a week, stays away from fried foods and foods with too much sugar, and eats a lot of fruit, vegetables and lean meat. He has lost 13 kilograms over the past three years.
“It’s a constant battle to stay healthy,” he says. “But my father died at the age of 50. I just turned 25, and that weighs on me.”