Another reason for kids to trim down

Obese children and those at risk for obesity show early signs of heart disease -- similar to that seen in obese adults, U.S. researchers say.

"In the patients who are obese, the rate of motion of heart muscle changed," Dr. Angela Sharkey, an associate professor of pediatrics at Washington University School of Medicine and a pediatric cardiologist at St. Louis Children's Hospital, said in a prepared statement. "As a child's BMIA (body mass index for age) increases, we see alterations in both the relaxation and contraction phase of the heartbeat. Many of these changes that have been seen in adults were assumed to be from long-standing obesity, but it may be that these changes start much earlier in life than we thought."

About 19 percent of American children ages 6 to 11 and 17 percent of those ages 12 to 19 are overweight, according to the U.S. Centers for Disease Control and Prevention.