May 4--KIDS IN OREGON -- unlike those in 49 other states -- are getting leaner, a new study suggests.
Problem is, experts can't explain why Oregon has veered from the extreme weight-gain trend that continues at an alarming rate elsewhere.
The prevalence of obesity among 10- to 17-year olds climbed 10 percent nationwide, and it doubled among girls in two states: Arizona and Kansas. But Oregon's youth obesity rate fell by 32 percent between 2003 and 2007, researchers with the U.S. Department of Health and Human Services reported this week.
"It seems quite substantial," said Gopal Singh, an epidemiologist with the U.S. Health Resources and Services Administration. "We don't know precisely the reasons for it."
Singh and others tracked obesity using the National Survey of Children's Health, a telephone survey of parents. The researchers used height and weight to calculate whether children were overweight or obese.
More than 16 percent of U.S. children qualified as obese (defined as having a body mass index at or above the 95th percentile for children historically, before the obesity epidemic began). From state to state, researchers found stark differences.
Rates of obesity in 2007 pushed above 20 percent in Alabama, Illinois, Kentucky, Louisiana, Mississippi, Tennessee and Texas, compared with a national low of 9.6 percent in Oregon, according to the study published Monday in Archives of Pediatrics and Adolescent Medicine. Obesity appeared to drop in several states, but only Oregon showed a statistically significant decline.
Christina Bethell, an associate professor at Oregon Health & Science University who has independently analyzed the national survey data, said states with high rates of obesity might be able to learn from states with low rates.
"The value of this type of national data is exactly this -- it allows us to see where things are improving and target those areas for learning," Bethell said.
But researchers are still trying to figure out what's driving the trend in Oregon. State surveys using different methods suggest that obesity rates, while lower than the national average, continue to increase, said Karen Girard, health promotion manager with the state Public Health Division.
The Oregon Healthy Teens Survey found that between 2001 and 2007, eighth-graders who are obese increased from 7.3 percent to 10.6 percent, and 11th-graders who are obese increased from 6.7 percent to 10.2 percent. The state survey draws on questionnaires filled out by students in school, and includes only eighth- and 11th-graders, which could account for differences from the national survey.
"There are certain states with much bigger problems," Girard said. "But childhood obesity is still a major public health problem here -- more than one in five Oregon youth are overweight or obese." In the new federal study, 24.3 percent of Oregon kids were overweight, a rate unchanged since 2003.
Bethell and colleagues, in a study reported in March, called attention to factors at home and in neighborhoods that seem to promote weight gain and obesity.
-- Poverty -- Children in low-income households are more than twice as likely to be overweight or obese as those in wealthy households.
-- Television viewing -- Children with TVs in their rooms or who watch more than two hours a day are 50 percent more likely to be overweight.
-- No parks -- Excess weight gain is 20 percent more common among children in neighborhoods without parks or recreation centers, regardless of socioeconomic status or health coverage.
-- No regular source of medical care -- Children lacking an established primary care provider are also more likely to be overweight or obese (34.7 percent versus 28.9 percent among those with an established caregiver). Singh's study found that being African American increased the risk of obesity by about 71 percent, and being Latino increased the risk by about 76 percent.
But Singh said ethnicity, poverty and inactivity patterns can't account for Oregon's low rate of obesity. Singh and colleagues used a statistical model to subtract the influence of these factors and still found that Oregon children were about half as likely to be obese as children in Illinois, Tennessee, Kentucky, West Virginia, Georgia and Kansas.
Oregon lawmakers have taken steps to reduce junk food in schools by setting nutrition standards for all foods and beverages sold in vending machines, student stores and a la carte lines in school cafeterias. State lawmakers also have boosted requirements for physical education in schools. But these laws were passed in 2007 -- too late to account for Oregon's performance in the new study.
A task force created by the Oregon Legislature in 2007 asked lawmakers for $10 million a year for an obesity prevention and education program starting in 2009. But the latest budget passed by the Legislature included no funding for it.
"We still have a long ways to go," Girard said.
Under the Healthy People 2010 initiative, states were expected to reduce their rates of childhood obesity to 5 percent this year. Girls in Wyoming and Montana came closest, with obesity rates of less than 7 percent.
-- Joe Rojas-Burke
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