Over the last decade, childhood obesity has grown into an epidemic, reflected in soaring rates of type 2 diabetes and recommendations that pediatricians check toddlers for elevated cholesterol.

What hasn't been as clear is how early to intervene.

A study presented at a pediatric research program on Friday suggested obesity prevention efforts should begin as early as age two, when children reach a "tipping point" in a progression that leads to obesity later in life.

"This study suggests that doctors may want to start reviewing the diet of children during early well-child visits," said John W. Harrington, M.D., a pediatrician at Virginia's Children's Hospital of The King's Daughters (CHKD). "By the time they reach eight years old, they're already far into the overweight category, making treatment more difficult."

The study examined records of 111 overweight children from a suburban pediatric practice. All of the children had their height and weight measured at least five times during pediatric visits. The average age was 12.

Children whose body mass index exceeded that of 85 percent of the general population were classified as overweight. Researchers charted the recorded body mass index of the children from infancy. through They found that the obese children had started gaining weight in infancy at an average rate of .08 excess BMI units per month. On average, they began this progression at three months of age.

Over half the children could be classified as overweight at two years old, 90 percent before reaching their fifth birthday.

Vu Nguyen, a second year student at Eastern Virginia Medical School, CHKD's academic partner, said the results surprised him.

"I didn't think that that obesity would start that early," said Nguyen, who presented the results Friday at a pediatric research scholars program.

Nguyen conducted the study with Harrington and Lawrence Pasquinelli, M.D., a pediatrician with Tidewater Children's Associates in Virginia Beach, Va.

More research is needed to determine the causes of early obesity including "information on family history and the dietary and exercise habits in infancy," said Harrington, an EVMS associate professor. "We may then have to look prospectively to see what interventions work in reversing this trend."