DALLAS (American Heart Association) -- The cholesterol-lowering drug, simvastatin, significantly reduced cholesterol levels in children with inherited high cholesterol, according to an international study published in the rapid access issue of Circulation: Journal of the American Heart Association.

This randomized, double-blind, placebo-controlled trial is the most extensive study of cholesterol-lowering in children performed to date.

"We found that simvastatin at doses up to 40 milligrams (mg) is a well-tolerated and effective therapy for children with inherited high cholesterol. In addition, the drug exhibited a safety and tolerability profile similar to that seen in adults and does not influence growth and pubertal development," says lead author Saskia de Jongh, M.D., of the department of vascular medicine and Emma Children's Hospital of the Academic Medical Center at the University of Amsterdam in the Netherlands.

Inherited high cholesterol, known as heterozygous familial hypercholesterolemia (heFH), is common and caused by mutations in the receptor gene for low-density lipoprotein (LDL), the so-called bad cholesterol. People with this disorder show symptoms of heart disease at a young age. Untreated, they have a 50 percent risk of developing heart disease by age 50.

A total of 173 heFH children (98 boys and 75 girls) were included in the study. The children were between 9 and 18 years old and were from seven countries. They were randomized to take either simvastatin or placebo. The drug was started at 10 mg/d and gradually increased to 40 mg. After 48 weeks, there were significant reductions in all measures of cholesterol: LDL dropped 41 percent; total cholesterol decreased 31 percent; apolipoprotein B (a protein component of lipids) was down 34 percent; very low-density lipoprotein declined 21 percent; and triglycerides fell 9 percent.

The drugs didn't affect the growth or maturation of the children.

The U.S. National Cholesterol Education Program recommends cholesterol-lowering drugs for children over 10 years old whose LDL remains high after dietary changes. Researchers say, however, that the long-term effectiveness of dietary changes is poor, and the lipid-lowering success of the drug is modest.

They few studies to evaluate statin therapy in children and adolescents showed good effectiveness, but "they were short-term, had a limited sample size, were mostly conducted in boys, or did not provide extensive information about growth and development," note the authors.