Obese children as young as 10 had the arteries of 45-year-olds and other heart abnormalities greatly increasing their risk of heart disease, say doctors who used ultrasound tests to take a peek inside.
The studies, reported Tuesday at an American Heart Association conference, found about a third of American children are overweight and one-fifth are obese.
"It reiterates what we know - which is there's an obesity epidemic," Dr. Travis Stork, host of the T.V. show "The Doctors," tells CBS News' The Early Show. "Nine million kids are overweight. This is a study of 70 kids, but they're looking at the arteries at the average age of 13. And their arteries are the age of a 45-year-old.
"In the world of medicine, there's a saying: 'You're only as young as your oldest part.' This is going to lead to strokes, heart attacks. This is probably going to take five, ten, 15, 20 years off these kids' lives."
Many parents think "baby fat" will melt away as kids get older. But research increasingly shows fat kids become fat adults, with higher risks for many health problems.
"Obesity is not benign in children and adolescents," said Dr. Robert Eckel, a former heart association president and cardiologist at the University of Colorado-Denver.
The American Academy of Pediatrics recently recommended cholesterol-lowering drugs for some kids, he noted.
Raghuveer wanted to see if early signs of damage could be documented. She and colleagues used ultrasound to measure the thickness of the wall of a major neck artery in 70 children, ages 10 to 16. Almost all had abnormal cholesterol and many were obese.
No one knows precisely how thick a 10-year-old's artery should be, since they're not regularly checked for signs of heart disease, but they do know that they should not look like those of people much older and larger.
Researchers used tables for 45-year-olds, who often do get such exams, found the kids' "vascular age" was about 30 years older than their actual age.
A separate study tied childhood obesity to abnormal enlargement of the left atrium, one of the chambers of the heart. Enlargement is a known risk factor for heart disease, stroke and heart rhythm problems.
Julian Ayer, a researcher at Royal Prince Alfred Hospital Sydney Australia, did ultrasound exams on 991 seemingly healthy children ages 5 to 15. He saw a clear link between rising weight and size of the left atrium.
A third study by Dr. Walter Abhayaratna of Australian National University in Canberra, Australia, found impairment in the heart's ability to relax between beats in children who were overweight or obese.
The study involved the first 150 children participating in a larger community-based study.
Earlier research, he helped conduct, found more rigid arteries in such children - a possible sign of plaque deposits starting to form.
"Even at this young age of 10, you can have children who have got arterial stiffness who are comparable to 30- and 40-year-olds," he said.
Dr. Michael Schloss, a New York University heart disease prevention specialist, said the evidence shows obesity is more than a cosmetic issue for children.
"If you've seen what's on the menu for most school lunches, these findings are no surprise," he said. "The time has come to seriously deal with the issue of childhood obesity and physical inactivity on a governmental and parental level."