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Kids Not Only Obese, They're Extremely Obese

Study: Extreme Obesity in 7% of Boys, 5% of Girls; as High as 12% in Some Ethnic Groups
WebMD Health News
Reviewed by Laura J. Martin, MD


March 18, 2010 -- Extreme obesity has reached ''alarming'' levels among children, according to a new study that looked at the weights and heights of more than 710,000 children aged 2 to 19.

''The prevalence of extreme obesity was much higher than we thought," says the study’s lead author, Corinna Koebnick, PhD, a research scientist at Kaiser Permanente in Southern California, a large prepaid health plan.

''Seven percent of boys and 5% of girls -- that is scary," she tells WebMD. That was the overall prevalence of extreme obesity she found. Before the study findings, Koebnick says, she would have expected perhaps 3% to 5%.

And the 7% and 5% figures are overall. For some ethnic groups, the prevalence of extreme obesity was much higher -- up to nearly 12%.

Extreme Obesity in Children: Study Details

Koebnick and her colleagues looked at electronic medical charts that had the height and weight of more than 700,000 children who had inpatient and outpatient visits in 2007 and 2008.

The sample studied was gender-balanced, with 357,205 boys and 353,744 girls.

They classified them as overweight, obese, or extremely obese.

Overweight is defined as the 85th or higher percentile on the growth charts, according to guidelines from the CDC. Obese is defined as the 95th percentile or higher.

"Extreme obesity is defined as 120% of the 95th percentile for weight for age and sex," Koebnick says.

In simpler terms, Koebnick says, ''For a 10-year-old boy or girl, you would expect him or her to weigh about 70 pounds." If the child weighs 140 pounds, that would be extreme obesity, she says.

''This is the first study using the new CDC definition of extreme obesity," she says.

Extreme Obesity in Children: Findings

Koebnick's team found:

  • 37.1% of the children were overweight
  • 19.4% were obese
  • 6.4% were extremely obese

Then they looked at gender and ethnic or racial differences. The prevalence of extreme obesity was highest in Hispanic boys, with as many as 11.2% being extremely obese, and in black girls, with as many as 11.9% of them extremely obese.

The prevalence of extreme obesity peaked at 10 years in boys and at 12 and also 18 in girls, the researchers found.

''This is a serious health issue,'' Koebnick says. ''These children are very likely to continue to be obese adults and face all the health consequences that come with obesity at a very early age.'' That includes heart disease and diabetes, among other ailments, she says.

Extreme Obesity: Second Opinion

The findings of the new study are no surprise to Lisa Goldman Rosas, PhD, postdoctoral fellow in family and community medicine at the University of California San Francisco School of Medicine, who has researched obesity in Hispanic children. The finding of increased obesity among Hispanic and black children has been consistent, she says. “That’s shown in national data, other studies of Kaiser populations,’’ and other research, she says.

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