Extreme Obesity is Prevalent in Children and Adolescents

Nancy Fowler Larson

September 18, 2010

March 18, 2010 — More than 7% of American boys and 5% of American girls are extremely obese, according to a study published online March 18 in the Journal of Pediatrics.

"The American Medical Association and the Centers for Disease Control and Prevention...recommendations on prevention, assessment, and treatment of childhood obesity are based on relatively limited knowledge about extreme childhood obesity at the population level," write Corinna Koebnick, PhD, research scientist, Kaiser Permanente Southern California's Department of Research and Evaluation, Pasadena, and colleagues. "Newer data on recent trends are not available. The present economic burden and health consequences are largely unknown and ill defined."

Reliable figures do exist for nationwide childhood obesity, which affects 17.1% of boys and 15.5% of girls. To determine the scope of extreme obesity in a multicultural, racially diverse population, the research team conducted a cross-sectional study in of 710,949 children aged 2 through 19 years. Approximately half were Hispanic. All were enrolled between 2007 and 2008 in a managed healthcare system that recorded information about height and weight, using electronic health records.

The researchers employed Centers for Disease Control and Prevention definitions for obesity and overweight, which include:

  • Extreme obesity: weight more than 1.2 times the 95th percentile, or body mass index (BMI) greater than or equal to 35 kg/m2

  • Obesity: weight higher than the 95th percentile, or BMI of 30 kg/m2 or more

  • Overweight: weight above the 85th percentile, or BMI of 25 kg/m2 or more

Among other findings, the study authors discovered that more boys are extremely obese than girls, and that the condition varies between sexes and among ethnic groups, as follows:

  • 7.3% of boys and 5.5% of girls were extremely obese

  • Extreme obesity peaked at 10 years of age in boys and at age 12 years in girls, who also demonstrated a second peak at ages 18 years (P value for sex × age interaction = .036); rates of extreme obesity are similar for boys and girls after age 18 years

  • Hispanic boys (as many as 11.2%) and black girls (up to 11.9%) were the heaviest of all children

  • The percentage of extreme obesity was lowest in Asian-Pacific Islanders (2.2%) and non-Hispanic white children (3.3)

  • Extremely obese children are at risk for conditions including heart disease, type 2 diabetes, fatty liver disease, and joint problems decades before those of normal weight

"Children who are extremely obese may continue to be extremely obese as adults, and all the health problems associated with obesity are in these children's futures," Dr. Koebnick said in a press release. "Without major lifestyle changes, these kids face a 10 to 20 years shorter life span and will develop health problems in their twenties that we typically see in 40-60 year olds."

The investigators acknowledged that race and ethnicity information was missing for more than half the participants. However, the study findings did not change when figured only for those whose race and ethnicity was known. Researchers also noted that because the data were entered manually, there may have been some inaccuracies. Weighing conditions may have also affected the data, with an undetermined number of children likely weighed while wearing shoes and/or heavier winter clothing.

Subsequent studies will explore the future implications of extreme obesity and its treatment.

"Now we are trying to quantify the health risks and long-term effects associated with extreme obesity, determine which groups are affected most, and develop strategies for population care management to reduce these health risks," Dr. Koebnick said in the press release. "Children's health is important and we have a long way to go."

Kaiser Permanente Direct Community Benefit Funds supported the study. The study authors have disclosed no relevant financial relationships.

J Pediatr. Published online March 18, 2010.


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