March 11 (HealthDay News) -- In yet another sign that obesity poses health risks at any age, new research shows that overweight children as young as age 3 can begin to show signs of cardiovascular disease risk factors.
About 24 percent of U.S. children aged 2 to 5 are overweight, defined as having a body-mass index (BMI) in the 85th percentile or above for their height and age. That number rises to 33 percent among children aged 6 to 11, according to the U.S. Centers for Disease Control and Prevention.
Using data on 3,098 children aged 3 to 6 taking part in the National Health and Nutrition Examination Survey, researchers analyzed levels of HDL, or "good," cholesterol and C-reactive protein, a marker for inflammation that can warn of cardiovascular disease.
They found that children with high BMIs and large waist circumferences were more likely to have elevated levels of C-reactive protein and lower levels of HDL cholesterol than children of normal weight. Data on LDL, or "bad," cholesterol was not available.
"Overall, as waist circumference and body-mass index increases, HDL cholesterol decreases and C-reactive protein increases," said study author Sarah Messiah, a research assistant professor at the University of Miami. "It's pretty clear that even at this young age, these cardiovascular risk factors are in motion."
The findings were expected to be presented Wednesday at the American Heart Association's Cardiovascular Disease Epidemiology and Prevention annual conference, in Palm Harbor, Fla.
About 12 percent of children aged 2 to 5 are obese, defined as having BMIs in the 95th percentile or above for their height and weight, according to the CDC. Among children aged 6 to 11, 17 percent are obese.
In the study, researchers noted that links between children's weight and levels of cholesterol and C-reactive protein varied according to ethnicity, gender and race.
Elevated BMI and waist circumference significantly predicted higher C-reactive protein levels in white girls and in black and Hispanic boys.
High BMI and waist circumference predicted lower HDL cholesterol in Hispanic boys and girls, while a high BMI was linked to elevated total cholesterol in black boys.
Researchers said the differences could have to do with the children's diets, genetics or other lifestyle factors.
But researchers stressed that the key message of the study was that all children should have their BMI and waist circumference monitored, and if the numbers are found to be creeping up, doctors and parents should intervene.
"It's frightening," Messiah said. "We are in uncharted territory. We have never had this number of children this heavy so young. We don't know the cumulative effect of all of these years of having all of your organs -- heart, kidneys, liver, heart, pancreas -- under stress from being overweight."
While worrisome, the findings are not surprising, said Dr. Ronald Krauss, director of atherosclerosis research at Children's Hospital Oakland Research Institute. In adults, the relationship between obesity and elevated LDL cholesterol and C-reactive protein has been well-established.
"It reinforces how serious it is and how much of an effort it's going to take to reduce the risk by going back to early childhood," Krauss said.
This summer, the American Academy of Pediatrics recommended children as young as 2 start having their cholesterol levels screened if they have a family history of heart disease or high cholesterol, and that screening should start no later than 10.
They also recommended, controversially, that children as young as 8 be given cholesterol-lowering drugs.
Both Messiah and Krauss are opposed to children aged 3 to 6 taking statins; the focus should instead be on better nutrition and more physical activity.
SOURCES: Sarah Messiah, Ph.D., M.P.H., research assistant professor and epidemiologist, University of Miami; Ronald Krauss, M.D., director, atherosclerosis research, Children's Hospital Oakland Research Institute; March 11, 2009, presentation, American Heart Association's Cardiovascular Disease Epidemiology and Prevention annual conference, Palm Harbor, Fla.