Obese children have neck arteries that have prematurely aged and look more like those of 45-year-olds, new research says, putting them at high risk for future heart disease and high cholesterol.

After measuring the inner-wall thickness of the carotid (neck) arteries in 70 children, researchers found the children's vascular age was 30 years older than their real age.

Vascular age is the age at which the thickening is normal for a subject's gender and race.

"There's a saying that 'you're as old as your arteries,' meaning that the state of your arteries is more important than your actual age in the evolution of heart disease and stroke," Dr. Geetha Raghuveer, associate professor of pediatrics at the University of Missouri Kansas City School of Medicine and cardiologist at Children's Mercy Hospital, said in a statement. "We found that the state of the arteries in these children is more typical of a 45-year-old than of someone their own age."

The average carotid artery intima-media thickness (CIMT) measurement was 0.45 millimetres, with the highest being 0.75 mm.

The higher the CIMT reading, the more plaque is built up in the arteries that allow blood to flow to the brain. When these arteries become constricted, it can lead to heart attack and stroke.

The findings will be presented Wednesday at the American Heart Association's Scientific Sessions 2008 conference in New Orleans.

The researchers used ultrasounds to measure the artery thickness in their study subjects, who had an average age of 13.

The study found that the subjects had abnormal levels of one or more types of cholesterol: high levels of low-density lipoprotein (LDL), the so-called bad cholesterol; low levels of high-density lipoprotein (HDL), the good cholesterol; or high triglyceride levels, which is the amount of fat circulating in the blood.

On average the children had:

• cholesterol levels of 223.4 milligrams per declitre (mg/dL), less than the reading of 170 recommended by the American Heart Association.
• LDL levels of 149.8 mg/dL, more than the acceptable 110.
• triglyceride levels of 151.9, which is higher than the recommended cap of 150.

The researchers found that having a higher body mass index (BMI) and higher triglyceride levels had the biggest impact on CIMT.

The 38 children who had high triglyceride levels had a CIMT reading above the 25th percentile for the average 45-year-old, which means these children "had better get serious in doing everything they can in terms of changing their diets and activity," Raghuveer told CTV News.

Previous research has shown that CIMT can be reduced when high-risk children take cholesterol-lowering drugs. As well, other studies have shown that exercise can improve blood-vessel function in children with a high BMI.

"One hopes that most of these kids won't have to go to the cholesterol-lowering drugs, but will go for lifestyle changes," Dr. Ruth McPherson of the Ottawa Heart Institute told CTV News. "But a few will require medications."

Further studies must be conducted to determine if exercising, losing weight or taking medication for high triglyceride levels can lower existing plaque buildup, Raghuveer said.

With a report from CTV's medical specialist Avis Favaro and senior producer Elizabeth St. Philip