CORRECTED: One-fifth of US teens have unhealthy cholesterol

(Corrects AAP recommendations in fifth and sixth paragraphs)

By JoAnne Allen

WASHINGTON (Reuters) - One in five American teens has unhealthy cholesterol levels, a major risk factor for heart disease in adults, the U.S. Centers for Disease Control and Prevention said on Thursday.

The heavier teens were, the more likely they were to have high cholesterol but even 14 percent of teens with normal body weight were found to have unhealthy cholesterol levels, the CDC said.

CDC researchers studied data on 3,125 teens collected from the National Health and Nutrition Examination Survey for 1999 through 2006.

They found that 20.3 percent of young people aged 12 to 19 and more boys than girls had unhealthy cholesterol levels.

The study found that, based on American Academy of Pediatrics guidelines, a third of teens would be eligible for cholesterol screening based solely on being overweight or obese.

The AAP also recommends screening for young people who have a family history of high cholesterol or premature heart disease.

The researchers analyzed measurements of low-density lipoprotein -- LDL or so-called bad cholesterol; high-density lipoprotein, the HDL or "good," cholesterol; and triglycerides.

Bad cholesterol can help clog arteries while good cholesterol carries away the bad stuff. People should aim for low LDL and triglycerides and high HDL.

Ashleigh May of the CDC, who led the study, said the results were "very concerning."

"It's a large proportion of the youth that have at least one abnormal lipid level. That is concerning given the long term implications for heart disease," May said in a telephone interview.

Unhealthy cholesterol levels, which often begin during childhood and adolescence, are a big risk factor in heart disease, the No. 1 cause of death among adults in the United States.

"We really want to make sure that clinicians are aware of lipid screening guidelines and lifestyle interventions that are recommended, for youth, especially overweight and obese youth," May said.

"For all youth, healthy eating habits and physical activity are good ways to reduce their risk for abnormal lipids and heart disease in the long term."

(Editing by Cynthia Osterman)