Extreme Adolescent Obesity in US Almost Triples in 25 Years

Marcia Frellick

June 07, 2016

Obesity among adolescents aged 12 to 19 has doubled over the past 25 years to 20.6% of that population, researchers from the US Centers for Disease Control and Prevention (CDC) have found. Extreme obesity in that age group more than tripled, from 2.6% to 9.1%.

The findings, published in the June 7 issue of JAMA, also show that obesity prevalence among 2- to 5-year-olds increased until 2003–2004 but then fell and stabilized at 9.4% in 2013–2014. Among children 6 to 11 years old, the prevalence increased until 2007–2008 and then leveled at 17.4% in 2013–2014.

The researchers used the latest data from the National Health and Nutrition Examination Surveys (NHANES), which are conducted every 2 years, and then they looked at how those numbers fit with patterns since 1988.

Lead author Cynthia Ogden, PhD, of the National Center for Health Statistics with the CDC, told Medscape Medical News these data have the advantage of documented height and weight instead of reported measurements, which tend to underestimate weight and overestimate height.

Previous obesity studies in this age group have shown inconsistent results, and part of the problem lies in using body mass index (BMI) for comparisons, she and her coauthors say.

They write: "There are racial and ethnic differences in body fat at the same BMI level. Among children and adolescents, the definition of obesity is statistical. Children and adolescents are compared with a group of US children in the 1960s to early 1990s, so the prevalence of obesity is dependent on the characteristics of the age-specific population during that period. In addition, among young children, small changes in weight can lead to relatively large changes in BMI percentile."

NHANES measurements are standardized over time and numbers go directly from the scale into the database, reducing the potential for recording errors.

Looking at a Quarter Century Paints a Clearer Picture

Measurements from 40,780 children and adolescents (average age, 11 years) between 1988–1994 and 2013–2014 were analyzed. Obesity was defined as a BMI at or above the sex-specific 95th percentile on the CDC growth charts. Extreme obesity was defined as a BMI at or above 120% of the sex-specific 95th percentile on the CDC charts.

Dr Ogden said they decided to look back 25 years because there had been no significant increase in any of the youth age groups over the past decade and, in fact, there was a decrease among 2- to 5-year-olds.

Extending the timeframe painted a clearer picture of patterns.

Researchers were also interested in whether the head of household's education level or other demographic variables made a difference.

In the subset of years 2011 to 2014, there were significant differences in obesity and extreme obesity by age, race, and education level of the head of the household.

Obesity odds were higher among non-Hispanic black children and adolescents (19.5%) (odds ratio [OR], 1.34) and Hispanic children and teens (21.9%) (OR, 1.48), compared with non-Hispanic white children and teens.

In contrast, obesity odds were lower for non-Hispanic Asian children and adolescents (8.6%; OR, 0.57) compared with non-Hispanic white children and adolescents.

The odds of obesity among children was also higher (OR, 1.41) when the head of the household had a high school degree (21% prevalence) than when that person had education beyond a high school degree (14.1% prevalence).

Findings were the same in relation to extreme obesity, the researchers found.

The authors report no relevant financial relationships.

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JAMA. 2016;315:2292-2299. Abstract


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