A new national study — touted by the authors as the first to examine obesity in 3-year-olds — found that Hispanic children are twice as likely to be overweight or obese as black or white children.

The study focused on urban, low-income children and found that overall, 35 percent were overweight or obese. The researchers followed 1,976 children from birth in 20 U.S. cities. Their work, funded by the nonprofit Robert Wood Johnson Foundation, was published online this past week in the American Journal of Public Health. It will appear in the journal's print edition in February.

"I hope that people will take seriously the problem of childhood obesity," said Rachel Kimbro, the study's lead author and the Robert Wood Johnson Health and Society Scholar at the University of Wisconsin-Madison. "I think it startles people to hear that 3-year-olds are obese ... and the problem gets magnified as children age."

It's a concern that has not escaped leaders at Salt Lake City's Guadalupe School, an elementary and pre-kindergarten school that serves disadvantaged children, many of them Hispanic immigrants with non-English-speaking parents.

Guadalupe parent-educators coach parents on how to read with their children as well as on good nutrition and health — how to prepare healthy snacks and encourage healthy eating and activity.

Patty Walker, principal at Guadalupe, said that as part of the school's preschool curriculum, children are taught how to kick, throw and catch a ball, pump a swing and run, skip and hop to ensure they learn to be active early on.

"I am amazed at how many 3-year-olds I see that can't pedal a tricycle," Walker said.

Childhood obesity is a growing public health worry, and the new study is significant because it is among the first that looks at the problem's origins, said Dr. Daniel Hale, a pediatric diabetes specialist and a professor of pediatrics at the University of Texas Health Science Center at San Antonio.

"I'm seeing 10- and 11-year-olds who weigh over 200 pounds," Hale said. "This is absolutely becoming routine in our practice."

Overweight and obese children are far more common among low-income families, the researchers said. Among the general population, about 10 percent of children ages 2 to 5 are believed to be overweight (defined as weighing more than 85 percent of other children of the same age and sex) or obese (weighing more than 95 percent of children of the same age and sex), Kimbro said.

For the study, the researchers chose children more likely to be low-income, with two-thirds born to unwed mothers. About 20 percent were not low-income, Kimbro said.