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One in five American adolescents has unhealthy cholesterol and triglyceride levels, suggesting that targeted screening of youths would be a good idea, CDC researchers said.

Data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2006 indicated that 20.3% (95% CI 18.0% to 22.8%) of participants 12 to 19 years old had higher-than-normal levels of LDL cholesterol or triglycerides, or low levels of HDL cholesterol, according to Ashleigh L. May and colleagues at the CDC's National Center for Chronic Disease Prevention and Health Promotion.

They also found that about a third of American youths would be candidates for lipid screening on the basis of body mass index (BMI) value, under guidelines from the American Academy of Pediatrics.

Their findings, based on blood tests in 3,125 young NHANES participants, were published in the Jan. 22 issue of Morbidity and Mortality Weekly Report.

High LDL cholesterol was defined as at least 130 mg/dL. High triglyceride levels were 150 mg/dL or above. HDL cholesterol of 35 mg/dL or below was considered low. These applied equally across age groups.

Here is the overall prevalence of each individual lipid abnormality:

• High LDL: 7.6% (95% CI 6.2% to 9.3%)
• Low HDL: 7.6% (95% CI 6.3% to 9.2%)
• High triglycerides: 10.2% (95% CI 8.4% to 12.2%)

Those 18 to 19 years old were much more likely to have these abnormalities than younger adolescents: some 28.8% of participants in this age group had at least one, compared with 16.5% to 18.4% of those 17 and younger (P<0.05).

Prevalence of lipid abnormalities was also more common among white youths (22.4%) than among black (14.6%) and Hispanic (18.6%) participants (P≤0.05 for both groups versus whites). Girls were somewhat less likely than boys to have one or more abnormalities (prevalence ratio 0.7, 95% CI 0.5 to 0.9).

Not surprisingly, overweight and obese youths were much more likely than those of normal weight to have unhealthy lipid levels.

Some 43% of obese adolescents had at least one abnormality, as did 22% of those considered overweight for their age and height. Both were significantly higher than the 14.2% of normal-weight participants with abnormal lipid levels.

"Based solely on their BMI, 32% of all youths would be candidates for lipid screening," May and colleagues wrote.

An unsigned commentary by MMWR's editors noted that "untreated abnormal lipid levels in childhood and adolescence are linked to increased risk for cardiovascular disease in adulthood," but they stopped short of endorsing routine lipid testing for adolescents.

The American Academy of Pediatrics recommends screening youths with specific risk factors such as overweight and family history. The U.S. Preventive Services Task Force looked at the screening issue in 2007 and decided not to recommend for or against routine screening.

The MMWR editors suggested a strategy in line with the pediatrics group's recommendation. "Targeted screening of youths for abnormal lipid levels can identify those youths who might benefit from interventions that reduce the risk for CVD," they wrote.

"Based on the findings in this study, clinicians should be aware of lipid screening guidelines and recommended interventions for children and youths who are overweight or obese," the editors added.

Such interventions include behavior and nutrition counseling and, if lipid levels remain abnormal, drug treatment.

But the editors pointed out that fewer than 1% of NHANES participants included in the current study "had lipid levels high enough to warrant drug therapy according to AAP guidelines."

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