'Just for Teens' Cholesterol Analysis
New System Could Help Spot Risk for Future Heart Disease
Aug. 29, 2006 - A new system for interpreting cholesterol levels in teens could help better identify those at risk for heart disease as adults, researchers say.
Unlike the current guidelines, the proposed classification system factors in an adolescent's age and gender when determining normal and abnormal cholesterol levels.
This is important, says a researcher who developed the new system, because cholesterol levels are known to change greatly with normal growth, and they also differ by gender prior to adulthood.
"With the current system, very, very few young children would be considered at risk, even if they have very high cholesterol values for their age," Ian Janssen, PhD, tells WebMD. "And girls mature much earlier than boys. So at age 12 or 13, we might see different values in females than in males."
Pediatricians do not routinely test cholesterol levels in children and teens, and adolescents are rarely put on cholesterol-lowering drugs because they have a low risk for heart disease.
But it is increasingly clear that the buildup of fatty plaque in the arteries that leads to heart disease can begin in childhood, Janssen says.
Current U.S. guidelines, in place since the early 1990s, have the same thresholds for identifying abnormal cholesterol and triglyceride levels for all children and teens between the ages of 2 and 19.
To create the new classification system, Janssen and colleague Courtney Jolliffe, MSc, of Ontario's Queen's University, Kingston, examined data from the U.S. National Health and Nutrition Examination Surveys (NHANES) collected between 1988 and 2002.
They looked at total cholesterol, LDL (bad) cholesterol, HDL (good) cholesterol, and triglyceride measurements for some 6,000 study participants between the ages of 12 and 20 to develop age- and gender-specific growth curves, similar to those used to monitor height and weight.
The New System
Under the new classification, a 12-year-old boy's total cholesterol level would be considered high at 233 mg/dL or greater, while the corresponding numbers for 15- and 19-year-old males would be 220 mg/dL and 238 mg/dL, respectively.
A 12-year-old girl's total cholesterol would be considered high at 211 mg/dL or greater, as would a 15-year-old's. The problem number for a 19-year-old female would be 238 mg/dL or above.
The report is published in the upcoming issue of the American Heart Association journal, Circulation.