ORLANDO — The prevalence of morbid obesity has grown dramatically among American adolescents and children, according to an analysis of data collected by the most recent national health survey.
On the basis of data from the National Health and Nutrition Examination Survey (NHANES) 1999–2004, about 418,000 adolescents aged 12–19 had a body mass index (BMI) of at least 40 kg/m
This number represented about 1.3% of the adolescent population in the United States in 2000.
Included in this group total were 71,000 adolescents with a BMI of 50 kg/m
With another definition of severe obesity, 3.8% of American children aged 2–19 had a BMI at or above the 99th percentile for their age in the National Health and Nutrition Examination Survey 1999–2004 sample, reported Dr. Cook and his associates on the study.
This prevalence translates into about 2.7 million children.
By convention, children who are younger than 12 years of age are defined as severely obese if their BMI meets or exceeds the 99th percentile for age. This is because the usual definition of morbid obesity—40 kg/m
The spread of obesity is reflected by the fact that BMI levels that, several years ago, were only reached by the heaviest 1% of children in each age group has now been reached by 3.8% on average.
More specifically, the prevalence of BMIs at or above the 99th percentile for age jumped by more than 50% between the prior NHANES in 1988–1994 and the 1999–2004 survey, said Dr. Cook, who is a pediatrician at the University of Rochester (N.Y.).
“The high prevalence and rapid increase of this group of children and adolescents portend a large burden to the health care system,” the researchers said in their poster.
“The progress that we've made in preventing and treating cardiovascular disease in adults will be reversed by childhood and teenage obesity,” Dr. Cook commented in an interview.
The large increase in obesity rates between the current survey and prior surveys was the sharpest among Mexican Americans, African Americans, and racial and ethnic groups classified as “other.”
In contrast, there was essentially no change among those children who were classified as white.
In the NHANES of 1999–2004, the highest prevalence of a body mass index of 40 or greater was among African Americans, with 3.4% of this subgroup in that range.
The National Health and Nutrition Examination Survey of 1999–2004 collected data on 12,384 American children who were selected for a sample that represented the total American population at that time.