The good news, announced in February by researchers
at the U.S. Centers for Disease Control and Prevention (CDC),
received widespread media coverage and prompted first lady Michelle
Obama to say she was "thrilled at the progress we've made over the
last few years in obesity rates among our youngest Americans.
The new study, published online in the medical journal JAMA
Pediatrics, used the same data source as the CDC, but analyzed
obesity rates over a different timeframe. It found increases in
obesity for children age 2 to 19, and a marked rise in the
percentage who were severely obese.
Asheley Cockrell Skinner of the University of North Carolina at
Chapel Hill, who led the new study, said the main message of her
analysis is that childhood obesity rates have not improved.
"I don't want a study like the previous one to change the national
discourse," she told Reuters Health, referring to the CDC's work.
Obesity experts had already begun to question the large drop
reported by the CDC for children ages 2 to 5. In their February
paper the CDC scientists themselves acknowledged the statistical
limitations of their data.
CDC researcher Cynthia Ogden, who led the study released in
February, said in response that her report described trends over the
last 10 years and found "an apparent decline in obesity among
children ages 2-5 (which we said in the paper should be interpreted
"We're confident in our analysis for this time period," she wrote in
an email to Reuters Health on Monday,
NATIONAL HEALTH SURVEY
The February report from the CDC found that the rate of obesity
among children ages 2 to 5 fell to 8.4 percent in 2011-2012 from
13.9 percent in 2003-2004.
Skinner and her colleagues used the same data as the CDC
researchers, from the National Health and Nutrition Examination
Survey, but looked at a few additional years.
"In 2003 there was an unusual spike in the number for whatever
reason — probably an error," Skinner said. "When you take a long
view from 1999 to now, you don't see that decline."
About 27,000 U.S. children between the ages of 2 and 19 were
included in the survey between 1999 and 2012.
Children are considered obese when their body mass index, a measure
of weight in relation to height, exceeds that of 95 percent of their
peers of the same age and sex.
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Overall, obesity rates increased from 14.5 percent in the
1999-2000 survey to 17.3 percent in 2011-2012. There was also a
marked increase in the rate of severe obesity over the study period,
the researchers found. Among preschoolers age 2 to 5, the rate was
slightly lower, but that could have been due to chance.
"Even though we don't see huge increases in the rates of children
who are overweight or obese, there are clearly more in the
categories that are severely obese," Skinner said.
There were especially noticeable increases in the rates of severe
obesity among black boys, Hispanic girls and white girls, Skinner
Rates for all obesity categories remained relatively unchanged
between the 2009-2010 and 2011-2012 surveys.
Skinner said there is some evidence that intensive weight loss can
be beneficial for overweight and obese children, but intensive
weight loss programs are not widely available.
Referring to the CDC's conclusion that obesity among preschoolers
had fallen 43 percent, Dr Ihuoma Eneli, medical director for the
Center for Healthy Weight and Nutrition at Nationwide Children's
Hospital in Columbus, Ohio, said, "we definitely have to look to see
what the results are over the next few years to see if that 43
percent drop is sustained and a true decline."
JAMA Pediatrics, online April 7, 2014.
(Additional reporting by Sharon Begley;
editing by Genevra Pittman,
Michele Gershberg and Tom Brown)
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