Children who have high blood cholesterol levels probably will grow up to be adults with high blood cholesterol and have a higher-than-average chance of developing heart disease, several studies have shown.

That doesn't mean, however, that parents should run out and have their children tested or immediately put them on a low-fat diet, the experts currently agree.

"I think parents should first worry about their own cholesterol. If they are O.K., then I would be less concerned about the child," said Dr. Peter Kwiterovich, chief of the lipid research-atherosclerosis unit of Johns Hopkins University School of Medicine in Baltimore. "If it's high in the parents, then it may be a good idea to test it in the children."

There are no national guidelines on testing or treating children and adolescents under the age of 19. Most physicians don't recommend testing children unless there is a strong family history of heart disease or if the child has symptoms of excessive cholesterol in the blood.

"We have established that children with elevated cholesterol levels come from families where there is a higher incidence of coronary heart disease in the adults of that family," said Dr. William Weidman of the Mayo Clinic in Rochester, Minn. "It is probably an interaction of genetics and diet."

Even so, said Dr. Basil Rifkind of the National Heart Lung and Blood Institute and others, the best advice for parents is to relax. "You are talking about preventing a disorder that occurs in 30 or 40 or 50 years. With children, you have lots of time to work on this. Unless you are working with a child that has really high cholesterol, it is something you can be patient with."

What's more, while there is a general association between high cholesterol levels in children and high levels later in life, there is not a clear link to future heart disease. "We have not shown that if you have a high cholesterol level in an 8-year-old that it will predict the rate of heart attacks in a 50-year-old," said Hopkins' Kwiterovich.

For all Americans including children over 2, a 1984 National Institutes of Health consensus conference on cholesterol recommended "a prudent diet" that involved a general reduction of the number of calories consumed as fat and an increase in calories from complex carbohydrates. "One of the reasons to teach a prudent diet in childhood is that if you teach the children to eat good foods early in life, then it is much easier to follow later in life," Kwiterovich said.

No dietary restrictions are advocated "for children less than 2 years old. "It is prudent not to interfere with the child's nutrition at that point," Kwiterovich said. One of the dangers, he added, is that "conscientious parents put the children on {low-fat and low-cholesterol} diets and they don't get enough calories. The children need the calories for growth and development."

In those cases where children are tested, the experts currently agree that the child's total blood cholesterol level should be at or below 170 milligrams per deciliter of blood. At that point, most physicians would recommend no changes in diet.

If the child's total cholesterol is significantly higher, the test probably should be repeated to confirm the results and then, said Weidman, a measurement of the low-density lipoproteins, the LDLs, and of triglycerides should be made, just as in the adult recommendations.

Weidman said low-density lipoproteins should be about 105 to 110 and triglycerides should be at or lower than 100. If they, too, are high, then the physician may begin to intervene, primarily with diet.

Within the next month or so, the NHLBI's National Cholesterol Education Program will convene a committee of experts to evaluate what is known about cholesterol in children and decide what national recommendations should be made for them. The committee's report is due in about a year.

Physicians point out that blood cholesterol levels are only one factor in trying to cut down the heart disease risk factors in children as they become adults. "It is just as important to check their blood pressure, move them into aerobic exercise, try to keep their weight at desirable levels and don't let them start smoking," said Weidman.

"We can do this gradually," he said. "We have plenty of time."