NEW YORK (Reuters Health) - The childhood obesity epidemic is hitting some states much harder than others, threatening to further worsen geographic disparities in health, new research shows.

Pedestrians walk through Times Square in New York City in this August 28, 2007 file photo.

Adults in the southeastern US-the so-called “Stroke Belt”-are known to be fatter and sicker than Americans living elsewhere. And at least in terms of overweight and obesity, the same pattern holds for kids, Dr. Gopal K. Singh of the US Health Resources and Services Administration in Rockville, Maryland, and his colleagues found.

Singh and his team compared state-by-state changes in rates of overweight and obesity between 2003 and 2007, using data from the National Survey of Children’s Health. They report their findings in the Archives of Pediatrics and Adolescent Medicine.

The percentage of children 10 to 17 years old across the US who were overweight rose from 31 percent in 2003 to 32 percent in 2004, while obesity rates went from 15 percent to 16 percent.

But within states, there were much sharper differences, with the states that already had the biggest problems often showing the biggest jumps. For example, in 2003, 37 percent of 10- to 17-year-olds in Mississippi were overweight and 18 percent were obese; by 2007, those numbers had jumped to 45 percent and 22 percent, respectively.

Oregon had the fewest obese kids, at 10 percent; it also was the only state to show significant declines in childhood obesity and overweight between 2003 and 2007.

Overweight and obesity rose much more sharply for girls than boys across the US, and in many states. The percentage of obesity among boys was the lowest in Oregon, at 11 percent, and the highest in Arkansas, at 27 percent. Wyoming girls had the lowest rate of obesity (6 percent), while Texas had the highest (20 percent).

There were eight states where a third or more of the youth population was overweight in 2003, but 15 in 2007. What’s more, the “epidemic” of child overweight and obesity was no longer limited to mostly southeastern states by 2007, but had spread to the Midwest-and even Alaska.

The states with bigger childhood obesity problems were-no surprise-also the states where kids spent more time watching TV and less time being physically active. Singh and his team estimated that these and other social and environmental characteristics, for example ease of access to parks and playgrounds and availability of sidewalks and walking paths, accounted for more than 40 percent of the state-by-state differences.

It will take more investigation to find out what Oregon might be doing right, Singh said.

The next National Survey of Children’s Health will be done in 2011, Singh noted. It’s impossible to predict what it will find, he added; “I think the best thing at this point that we can anticipate is a stabilization of the trend. Hopefully we have seen the worst.”

SOURCE Archives of Pediatrics and Adolescent Medicine, online May 3, 2010.