NEW ORLEANS - Using carotid artery ultrasound with a high-resolution probe, researchers have found that vascular age is advanced in children who are obese or who have unfavorable lipid profiles, according to a report at this week's American Heart Association (AHA) meeting.
The carotid artery intima-media thickness (IMT) of about three-fourths of children and teens with these heart disease risk factors is comparable to that of a 45-year-old, said Dr. Geetha Raghuveer, a cardiologist at Children's Mercy Hospital in Kansas City, MO.
"Carotid artery ultrasound and estimation of vascular age may help further stratify children with risk factors who are at greatest risk for heart disease and need intensive management," she said.
Raghuveer and colleagues studied 70 children and teens ages 6 to 19 years, with an average age of 13 years. Nearly all (89%) were white, and 34 (49%) were male.
Forty of the subjects had a body mass index (BMI) above the 95th percentile for their age, and "almost all had some abnormality in their lipid profiles," Raghuveer said.
Specifically, 59 youngsters had total cholesterol levels greater than 170 mg/dL, 51 had low-density lipoprotein (LDL) cholesterol levels greater than 110 mg/dL, 17 had high-density lipoprotein (HDL) levels less than 35 mg/dL, and 43 children had triglyceride levels greater than 100 mg/dL.
The carotid artery IMT was calculated from multiple frames of the far wall of the common carotid artery, 2 cm proximal to the bifurcation, using semiautomated edge-detection software.
The children's average carotid artery IMT was 0.45 mm, which is more typical of adults in their mid-40s, Raghuveer said.
Next, the researchers gauged each child's vascular age by comparing his or her IMT measurement to IMT percentile tables published for a 45-year-old race- and sex-matched population.
"There are no population-based norms for children, so we plotted against this published standard for 45-year-olds. We defined advanced vascular age as any child above the 25th percentile for race- and gender-matched adults," she explained.
Using this definition, 75% of the children had advanced vascular ages, Raghuveer said.
High triglyceride levels -- above 100 mg/dL -- proved to be the strongest risk factor for advanced vascular age. Of children with advanced vascular age, 38 had high triglyceride levels and only 14 had triglyceride levels below 100 mg/dL, a significant difference.
BMI above the 95th percentile also was a strong predictor: Of the children with advanced vascular age, 26 had a BMI above this cutoff, while only four had lower BMIs.
In multiple regression analysis, weight, BMI, and systolic blood pressure remained significant predictors of mean carotid IMT.
"Childhood obesity is a public health problem. Determining vascular age using carotid intima-media thickness may help to assess the burden of atherosclerosis," Raghuveer said.
Dr. Stephen Daniels, Ph.D., chairman of the department of pediatrics at the University of Colorado in Denver, said that this and other recent studies "are really beginning to demonstrate that being overweight or obese in childhood is not innocuous." Daniels moderated a press conference to discuss the findings.
"Over the past 20 years, we've started seeing changes in risk factors that are of concern: higher blood pressure, higher triglyceride levels, and increases in waist circumference," he said.
The good news, Raghuveer said, is that the process can probably be reversed in these children.
"Children don't have as much hardening, or calcification, in their arteries," she said. "I'm optimistic we can improve the vessel walls and blood flow in adults through lifestyle and pharmaceutical interventions."
By Charlene Laino
AuntMinnie.com contributing writer
November 12, 2008
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