A recommendation from an influential doctors group that some children as young as 8 be aggressively treated with cholesterol-lowering drugs has triggered debate over whether there is enough scientific evidence to justify such a move.
Statins, already among the most widely prescribed drugs, have been shown to lower the risk of heart disease in certain adults. But there are no comparable long-term studies for children.
"We don't know the risks and the benefits," said Dr. Beatrice A. Golomb, a cholesterol expert at UC San Diego. "We don't really know the impact of long-term use."
The authors of the recommendation from the American Academy of Pediatrics concluded there was enough indirect evidence to suggest that starting treatment early makes sense in children with very high levels of cholesterol.
"The process that ends with a heart attack or stroke starts in childhood, even infancy," said Dr. Nicolas Stettler, a coauthor and pediatrician at the Children's Hospital of Philadelphia.
"The longer you slow down the process, the more you delay the progression," he said.
The guidelines, released Monday, are in response to the high rate of obesity among U.S. children and concerns that they could face increased risk of heart disease as adults.
The guidelines advise cholesterol testing for millions of children ages 2 to 10 who have a family history of early heart disease or other risk factors such as obesity or high blood pressure. Under the guidelines, those 8 and older should be considered for medication if they have a concentration of LDL, the so-called bad cholesterol, greater than 190 milligrams per deciliter.
The threshold drops to 160 milligrams per deciliter in children with a family history of heart disease or more than two other risk factors. In children with diabetes, the threshold for drug treatment is 130 milligrams.
Experts said those levels occurred only in children with a genetic predisposition to high cholesterol, including many who were of normal weight, and that under the guidelines, fewer than 1% of children would be considered for statins.
Children with these extremely high LDL levels are known to have an increased risk of heart disease later in life.
But some doctors predicted that the guidelines would lead to the use of drugs in children with only moderately high cholesterol levels.
"There may be some pressure to start them on drugs to make these numbers better," said Dr. Thomas B. Newman, an epidemiologist and pediatrician at UC San Francisco. He also worries that the acceptance of drug use would shift the focus of treatment away from diet and exercise.
The guidelines, produced by a seven-member panel and published in the academy's journal, Pediatrics, did not include any disclosures about the authors' ties to drug makers.
One author, Dr. Stephen Daniels, a pediatrician at Cincinnati Children's Hospital, has acknowledged working as a consultant for Merck & Co., which markets statins, and Stettler said he had participated in industry-funded clinical trials of cholesterol drugs.
Dr. Jerold F. Lucey, editor of the journal, said that disclosures weren't required for academy-issued guidelines because the panels were already rigorously vetted.
The academy issued a statement saying "there is no involvement by any commercial entity in the development of any statement or report emanating from the AAP."
The editors were "naive in expecting people would swallow those recommendations without letting us know if the participants had ties to the companies that make statins," said Dr. Jerome P. Kassirer, a professor at Tufts University School of Medicine and a former editor of the New England Journal of Medicine.
The idea of using cholesterol-fighting drugs in children is not new. Over the last decade, several clinical trials have shown that treatment with statins lowers their cholesterol levels.
In one study, children with extreme levels of cholesterol who were given statins had less thickening in their necks' carotid arteries than children on a placebo.
"You know what is going to happen to them if you don't treat them," said Dr. Peter O. Kwiterovich, a pediatrician and cholesterol expert at Johns Hopkins University who was not involved in making the guidelines. "They get heart attacks in their 30s, 40s and 50s."
There is no evidence from clinical trials in children that the drugs are damaging, he said. Growth, maturation and brain chemistry remained normal.
Most of the clinical trials involved teenagers. The authors of the guidelines settled on 8 as the minimum age for drug therapy because that was the age of the youngest patients in any clinical trial, Stettler said.
But the studies, the longest of which tracked children for four years, did not last long enough to show the long-term benefits of starting treatment earlier -- or the potential harms.