According to a study published in the May 28 issue of JAMA, US children and teens were no more obese in 2006 than they were in 1999 – a finding that is contrary to the increase in obesity that was found in prior years.

“In the United States, the prevalence of overweight among children increased between 1980 and 2004, and the heaviest children have been getting heavier,” write Cynthia L. Ogden, Ph.D. (Centers for Disease Control and Prevention (CDC), Hyattsville, Md.) and colleagues, authors of the study.

Ogden and colleagues reached their conclusions by updating the national estimates of the prevalence of young persons with high body mass indexes (BMI). From the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey (NHANES) – a nationally representative survey of the U.S. population – the researchers obtained height and weight measurements from 8,165 children and adolescents.

The researchers used the year-2000 sex-specific BMI-for-age growth charts from the CDC to define three levels of high BMI: at or above the 97th percentile, at or above the 95th percentile, and at or above the 85th percentile. These charts allowed outcome measures to be assessed according to age, sex and racial/ethnic group.

One main finding was that between 2003-2004 and 2005-2006, there was no statistically significant change in high BMI for age. Additionally, the researchers found no statistically significant trend in high BMI in the periods from 1999-2000, 2001-2002, 2003-2004, and 2005-2006.

The researchers then combined the 2003-2004 and 2005-2006 survey data to make detailed estimates of the prevalence of high BMI in the population. It was found that 11.3% of children and adolescents were at or above the 97th percentile of BMI for age (meaning that their BMIs were greater than 97% of the reference population used for the growth charts) for the 2003-2006 period. In the same time frame, 16.3% and 31.9% of children and adolescents had a BMI for age at or above the 95th and 85th percentiles of BMI for age, respectively.

High BMI prevalence estimates were found to vary along age and racial/ethnic groups. The authors report that non-Hispanic black and Mexican American girls had a greater likelihood of high BMI for age than non-Hispanic white girls. Mexican American boys were significantly more likely to have high BMI for age than non-Hispanic white boys.

An accompanying editorial, written by Cara B. Ebbeling, Ph.D., and David S. Lugwig, M.D., Ph.D. (Children’s Hospital Boston), adds:

“. do current CDC data suggest that the end of the pediatric obesity epidemic is in sight? After years of unremittingly bad news about increasing rates of pediatric obesity, Ogden et al report no increase in prevalence between 1999-2000 and 2005-2006. Perhaps recent public health campaigns aimed at raising awareness of childhood obesity and improving the quality of school food have begun to pay off. However, it is too early to know whether these data reflect a true plateau or a statistical aberration in an inexorable epidemic, and pre-existing racial/ethnic disparities show no sign of abating. On one point there is no uncertainty: without substantial declines in prevalence, the public health toll of childhood obesity will continue to mount, because it can take many years for an obese child to develop life-threatening complications.”

High Body Mass Index for Age Among US Children and Adolescents, 2003-2006
Cynthia L. Ogden; Margaret D. Carroll; Katherine M. Flegal
JAMA (2008). 299[20]:2401 – 2405.
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Written by: Peter M Crosta