Thursday, August 31, 2006

New Cholesterol Guidelines Proposed for Teens

Gender, age taken into account to assess future heart-disease risk

By Ed Edelson
HealthDay Reporter

TUESDAY, Aug. 29 (HealthDay News) -- Canadian researchers are reporting what they say is a better way to identify teens whose cholesterol levels put them at high risk for heart disease as adults.

The current guidelines, established in 1992 in the United States, have limited ability to single out younger people who will be at high risk in the future, said the research team led by Ian Janssen, a professor of kinesiology and epidemiology at Queen's University in Kingston, Ontario.

"The essential difference with our method is that it takes into account the age and gender of a teen when determining who is at risk," Janssen said.

The report was expected to be published in the Aug. 29 issue of Circulation.

Janssen and his colleagues used data from the U.S. National Health and Nutritional Examination Surveys conducted between 1988 and 2002. Information on more than 6,000 participants aged 12 to 20 was used to develop age- and gender-specific growth curves for total cholesterol, LDL ("bad") cholesterol, HDL ("good") cholesterol and triglyceride fat levels. These curves are similar to the curves used to monitor and estimate height and weight patterns in children and teens.

The cholesterol curves were then linked to adult cholesterol and fat levels that predict cardiovascular risk. The result is a reading that can predict a teen's future risk of heart disease, Janssen said.

The major advantage of the new guidelines is that they take into account the fluctuations in cholesterol and fat levels that occur with age, Janssen said. "We know that your cholesterol levels change significantly from age 2 to 20, changes that go with maturation," he said.

The current guidelines published by the U.S. National Cholesterol Education Program don't take those age-related changes into account, Janssen said. They simply say that any teen in the top 5 percent of readings is at risk, an entirely arbitrary level, he said.

"Why not choose the 90th percentile instead of the 95th?" he asked. "There is no real risk attached to either of these percentiles."

Gender must also be taken into account because the curves for the two sexes differ, the Canadian researchers said. For example, male levels of LDL cholesterol decrease early in the teen years, then start rising at about 15 years of age, while female levels increase steadily from 12 to 20.

The current federal guidelines, endorsed by the American Heart Association, recommend cholesterol screening tests for adolescents whose parents have abnormal cholesterol levels or if there is a family history of cardiovascular disease before age 50.

"Hopefully, physicians already are testing those teenagers," Janssen said. "Hopefully, this method provides a better way to identify those at high risk."

More information

For more on cholesterol testing, visit the National Library of Medicine.

SOURCES: Ian Janssen, Ph.D., professor, kinesiology and epidemiology, Queen's University, Kingston, Ontario, Canada; Aug. 29, 2006, Circulation


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