Even at ages 8 to 11, as many as 9.5% of obese children already have metabolic syndrome. That means they have at least three of these risk factors: abnormally large waist size, high blood-sugar levels, low levels of HDL "good" cholesterol, high blood fat levels, and high blood pressure.
"If a kid is age 8 with metabolic syndrome, it will take 10 years or less for that child to become a type 2 diabetic or develop heart disease," Messiah tells WebMD. "So as these kids enter adulthood, they could be faced with an entire life of chronic disease."
Obese kids aren't dropping dead in their teens, but by then, many have serious heart problems, says John K. Stevens Jr., MD, a cardiologist at Children's Healthcare of Atlanta's Sibley Heart Center.
Stevens sees more and more teens with dangerously high blood pressure that is reshaping their hearts. He sees teens with dangerously high levels of blood fats. He sees teens with plaque streaking the walls of their arteries. And he sees teens far down the road toward type 2 diabetes, a major risk factor for heart disease.
"I am very fearful that in the next 10 to 20 years we will have an explosion of type 2 diabetes and coronary artery disease as these very young, very obese kids become 20-year-olds and 30-year-olds," Stevens tells WebMD.
The problem isn't a heart disease epidemic. It's a child obesity epidemic, Stevens says -- and Messiah's numbers lead to the same conclusion.
The analysis comes from combined data on some 1,700 children ages 8 to 14 collected from 1999 to 2002 as part of the National Health and Nutrition Examination Survey (NHANES). The main findings:
About 17% of boys and girls ages 8 to 11 and 12 to 14 are overweight or obese.
Between 6.5% and 9.5% of overweight 8- to 11-year-olds have metabolic syndrome, depending on how the data are adjusted to account for sex, age, and ethnicity.
Between 26.3% and 52.4% of overweight 12- to 14-year olds have metabolic syndrome.
This does not mean that overweight kids who don't yet have metabolic syndrome are out of the woods.
"Children who are obese and who don't have these risk factors should not be feeling good about it, because they will have them down the road," Stevens warns. "When we hear of people dying of coronary artery disease in their 30s and 40s, we are shocked and amazed and say, 'That is too young.' But I am fearful we are going to be seeing coronary artery disease a lot earlier in these kids growing up obese."