A woman walks on the National Mall in Washington DC on August 13, 2010. Obesity in the United States has increased to 2.4 million obese Americans since 2007, according to a report released this week by the Centers for Disease Control and Prevention (CDC). UPI/Alexis C. Glenn | License Photo

LONDON, Nov. 27 (UPI) -- Obesity is a warning sign of eventual heart disease as early as age 9, British researchers say.

And if youngsters have not established a healthy weight by 15, they begin to show risk factors, according to the study published in the British Medical Journal Friday and reported in The Daily Telegraph.

Tam Fry of the National Obesity Forum said the study bolsters the case that obesity must be addressed at earlier ages.

"We have left things too late for far too long," he said. "If you start early enough, you might be able to nip it in the bud. We should be assessing our children on a routine basis."

In the Bristol University study, led by Professor Debbie Lawlor, more than 5,000 children ages 9 to 12 were measured for body mass index and other indicators of obesity. They were measured again at 15.

At 9, almost a quarter were either overweight (18.5 percent) or obese (4.5 percent). Those who remained so at 15 had significantly higher blood pressure, cholesterol and insulin levels than thinner children.

But those who lost weight tended to reduce their risk factors, with girls recovering better than boys.