Thursday June 19 3:40 PM EDT

-- Adults are not the only ones who should be concerned about cholesterol. The high number of obese Americans, both children and adults, are cause for concern, say health officials. And testing the cholesterol levels of children is one way to look for factors that may adversely affect children's heart health as they grow up.

A new study, from researchers at the University of Texas Houston Health Science Center, shows that current cholesterol testing guidelines for children may need updating, however.

The researchers tested the cholesterol levels of 678 children, ages 8 to 18, taking samples three times a year for four years. Though pediatricians have always used the same targeted cholesterol levels to evaluate children of all ages, and for both boys and girls, it turns out that this may not be appropriate.

"Our findings show that cholesterol levels are not constant during childhood and adolescence, but tend to peak around ages 10 to 11, depending on the sex, and decrease to a low level at 16 or 17, with girls maturing and exhibiting these changes about a year ahead of boys," one of the researchers, Dr. Darwin Labarthe, explains. "This means the current practice of testing for cholesterol in children by use of a single value for all ages and for both boys and girls should be reconsidered."

Labarthe and his colleagues are developing new testing recommendations that will be submitted for publication in the next few weeks and may be published later this year. The researchers' current study appears in the June 17 issue of Circulation.

In the meantime, Labarthe has advice for parents who take their children for physical exams and are concerned about cholesterol testing.

"In the U.S., where heart attacks continue to be the leading cause of death of the population as a whole, we all have problems with cholesterol. My advice to all parents and their children is to adopt a dietary pattern that limits fat intake, especially animal and dairy fats, which reduces cholesterol consumption. And they need a pattern of living that involves frequent strenuous or at least moderately strenuous activity."

Labarthe says families with a history of heart disease should pay particularly close attention to children's cholesterol levels. "Testing that comes in at the highest 25% level will identify a group that may need personal intervention or advice," he explains.

But he cautions that "a higher cholesterol value around age 10 or 12 is perhaps less indicative of future problems than is a similarly high level at 16 or 17, where, on average, the values decrease."

Because cholesterol levels fluctuate, parents may want to have children's levels tested more than once a year if they think their children are at high risk. But Labarthe said he and his colleagues are still evaluating that recommendation.

SOURCE: Circulation (1997;95:2636-2642)