Cholesterol Levels Fall Among Young - Wall Street Journal

By JENNIFER CORBETT DOOREN

WASHINGTONâ€"Cholesterol levels in U.S. children and adolescents dropped in the past two decades, according to federal health researchers, but a large proportion of young people still have abnormal levels that could place them at risk of prematurely developing heart disease.

The study showed that 8.1% of children and adolescents ages 6 to 19 had elevated total cholesterol levels between 2007 and 2010, a decline from 11.3% who had high cholesterol between 1988 and 1994. The findings, led by researchers at the Centers for Disease Control and Prevention, were published Tuesday in the Journal of the American Medical Association.

Cholesterol refers to types of fat that can be found in the blood. The two main types are LDL cholesterol, the "bad" kind that can clog blood vessels, and HDL cholesterol, the "good" kind that helps the body remove bad cholesterol. An elevated total cholesterol level in children and adolescents is represented by a reading of 200 milligrams per deciliter of blood or greater.

The findings might seem surprising given that obesity levels in children have been rising. The CDC has estimated that about 17% of children are obese, triple the level three decades ago. Obesity often is associated with increases in blood pressure and blood sugar as well as adverse changes in cholesterol levels, which in turn raise the risk of developing heart disease and diabetes.

"There are a lot of factors that can cause changes in blood cholesterol levels," said lead author Brian Kit of the CDC's National Center for Health Statistics. One possible factor, Dr. Kit said, is a drop in adolescent smoking rates and lower exposure to secondhand smoke. Some studies have shown that exposure to smoking can reduce good cholesterol.

Another factor might be a decline in consumption of trans fat, a type of processed vegetable fat that contributes to higher cholesterol. Some cities and states have banned trans fats in restaurants, while many food makers have substituted other types of oil in their products.

The proportion of children and adolescents who had any type of cholesterol problemâ€"involving too little "good" cholesterol or too much of the "bad"â€"fell to 22% in the 2007-10 period from 27% in the 1988-94 period.

Even with the improvement, the figures suggest that more than 1 in 5 children have some kind of cholesterol issue that may raise their risk of cardiovascular disease, the nation's leading cause of death.

Last November, for the first time, the National Heart, Lung and Blood Institute said a child's first cholesterol test should be done between ages 9 and 11, and repeated between ages 17 and 21. The recommendation reflects growing evidence that the biological processes underlying heart attacks and related diseases begin in childhood, although the diseases generally don't strike until middle age or later.

The new report isn't expected to affect those testing recommendations, which have also been endorsed by the American Academy of Pediatrics. Recommendations from that group are influential among doctors who treat children and adolescents.

Stephen Daniels, chairman of the task force that wrote the guidelines and a pediatrician at Children's Hospital Colorado, said the latest data represent good news but won't necessarily translate into a reduced risk of developing cardiovascular disease in adulthood.

"One of the biggest health challenges now is to figure out how to have kids stay at a low-risk status" by exercising and adhering to a healthy diet, he said.

The CDC study involved more than 16,000 people ages 6 to 19. Researchers used data collected as part of the National Health and Nutrition Surveys taken during three time periods from 1988 to 2010.

Total cholesterol levels, which include the "bad" and "good" kinds, were obtained using a blood test. Adolescents ages 12 to 19 didn't eat for several hours before their tests were taken, considered the most accurate way to measure cholesterol.

Write to Jennifer Corbett Dooren at jennifer.corbett-dooren@dowjones.com