It's often said, these days, that we're a nation of fatties. And, not coincidentally, we're also a nation of fatty livers.
Increasingly, millions of those livers belong to children -- though most of them don't know it, and neither do their parents and doctors.
Usually, no symptoms show up until damage has been done, damage that may ultimately lead to cirrhosis of the liver, liver cancer and end-stage liver disease.
Until the 1990s, no one knew that fatty livers were a problem in children, and now, doctors say, the situation has become serious. "If you were to go into any large California high school with a couple thousand students and screen, you'd expect 200 children with fatty livers," says Dr. Jeffrey Schwimmer, director of the Fatty Liver Clinic at Rady Children's Hospital in San Diego and associate professor of pediatrics at UC San Diego.
Schwimmer was lead author of a study published in the journal Pediatrics in October 2006 that found evidence that nearly 10% of children between 2 and 19 years old in San Diego County have fatty livers. If that percentage holds throughout the U.S., 6.5 million children are affected.
The data show that fatty livers in children are highly correlated with weight. About 80% of kids with the condition are obese or overweight. Nearly 40% of obese children have fatty livers.
"It's the most common serious complication of childhood obesity," Schwimmer says. And doctors fear it may cause serious problems for these children as adults. In a study published in the October 2006 issue of the journal Hepatology, researchers in Sweden followed up on adult patients an average of 14 years after they were diagnosed with fatty livers and found that most of them had diabetes or impaired glucose tolerance. Many had end-stage liver disease.
Experts say it is likely that children with fatty livers have a head start on these problems and may be at risk for developing them while still young.
To date, biopsies are the only effective diagnostic test for fatty livers. Diet and exercise are the only effective treatments. And it's a mystery why the condition can be harmless for many, yet dangerous for others.
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Under-the-radar disease
People with fatty livers are said to have nonalcoholic fatty liver disease. By definition, this disease occurs when 5% or more of the liver is fat. Often no damage is done, but in about 20% to 25% of cases, excess fat in the liver results in cell destruction and inflammation. At that point it becomes a condition known as nonalcoholic steatohepatitis, a form of hepatitis caused not by a virus but by too much fat.
