NEW YORK, Feb 25 (Reuters Health) - While U.S. rates of obesity haven't changed much in a decade, preschool age children are showing signs of a turnaround, with rates nearly halved in that time, according to a new federal study released on Tuesday.
Obesity rates among 2- to 5-year-old Americans dropped from 13.9 percent to 8.4 percent between 2003 and 2012, according to the findings published in the Journal of the American Medical Association. Overall, however, more than a third of U.S. adults and 17 percent of kids and teens are obese.
"The rapid increase in obesity we saw in the '80s and '90s has definitely slowed," epidemiologist Cynthia Ogden told Reuters Health. "There's some glimmer of hope in the new data in relation to the 2 to 5 year olds."
Ogden, a branch chief at the National Center for Health Statistics in Rockville, Maryland, a division of the Centers for Disease Control and Prevention (CDC), is lead author of the new study.
CDC said it was not clear what factors had led to the decline, but cited improvements in the food and physical activity available at childcare centers, a drop in consumption of sugary drinks and even an increase in breastfeeding rates, which have been shown to help prevent obesity later in life.
"This confirms that at least for kids, we can turn the tide and begin to reverse the obesity epidemic," CDC Director Tom Frieden said in a statement.
Not all the news on the national state of weight was positive, however. Since 2003, women 60 years and older have been growing fatter. Their rate of obesity rose from 31.5 percent to 38 percent over nine years, the study found.
Ogden and her colleagues used the annual National Health and Nutrition Examination Surveys to examine obesity trends in representative samples of Americans between the 2003-2004 survey year and 2011-2012.
A 5.5 percentage point drop in the obesity rate among 2 to 5 year olds mirrored decreases found among preschoolers in previous studies, the authors write.
A report published last year, for example, found that after doubling over 30 years, the obesity rate among low-income preschool children fell in 19 U.S. states and territories (see Reuters story of August 6, 2013 here: reut.rs/OuyauP).
Nonetheless, more than two-thirds of American adults and nearly one-third of youth aged 2 to 19 fell into the overweight or obese categories in 2011-2012.
For adults body mass index (BMI), a measure of weight relative to height, defines obesity. A BMI above 25 is considered overweight, and BMI over 29.5, which is equivalent to a 5-foot, 4-inch adult weighing 174 pounds, is considered obese.
For children, BMI calculations also factor in the weights of other kids in the same age group.
Dr. David Ludwig, a pediatrics and nutrition researcher at the Harvard School of Public Health in Boston, read the report as a tiny step forward in the fight against obesity.
"The key finding is that obesity prevalence throughout the U.S. population has not changed in the last decade and remains at historic highs," Ludwig told Reuters Health in an email.
He also cautioned that the decline in obesity rates among preschool kids could result from chance.
"Nevertheless, if real, the lower prevalence among young children would be an encouraging sign that national pediatric obesity prevention efforts - though still grossly inadequate - may be having some impact," he said.
Michael Jacobson, executive director of the Center for Science in the Public Interest, told Reuters Health he sees the report as a sign the obesity epidemic may have peaked.
But Jacobson, who was not involved in the study, also pointed out its data on how differently obesity impacts ethnic groups, with 82 percent of African-American women and 77 percent of Hispanic women overweight or obese, compared to 63 percent of white women in 2011-2012.
"That's a real health crisis," Jacobson said. "These numbers are crying out for some real action." SOURCE: http://bit.ly/1c9i5E4 Journal of the American Medical Association, online February 25, 2014. (Editing by Christine Soares, Michele Gershberg and Chizu Nomiyama)