It is another hazard to American teens caused by obesity.

Some overweight teens have severe liver damage caused by too much body fat. And a few of them have even needed liver transplants.

Experts warn that many more of them may need a new liver by the time they are in their 30s or 40s.

Some recent medical studies, and some doctors interviewed by The Associated Press, say the condition is being seen in kids in the United States, Europe, Australia and even some developing countries.

It's called nonalcoholic fatty liver disease, and it can lead to cirrhosis and liver failure or liver cancer.

The American Liver Foundation and other experts estimate that two percent to five percent of American children over the age of 5 have the condition. Nearly all of them are obese or overweight.