Body Mass Index Added to New Pediatric Growth Charts

New CDC pediatric growth charts introduced during the National Nutrition Summit, held May 30-31, 2000, now include tables to assess body mass index or BMI.

The acronym BMI may sound familiar because it is already commonly used in adults to assess weight problems by measuring a person's body fat. The BMI number is derived from a formula of weight in relation to height or wt/ht2 (weight in pounds divided by height in inches squared). The new pediatric growth charts include a BMI chart for boys and one for girls to give pediatricians and other health care practitioners who care for children another means of monitoring early signs of weight problems.

Dr. Kenneth Ellis, a Baylor College of Medicine professor of pediatrics who studies growth and body composition at the USDA/ARS Children's Nutrition Research Center, notes that many factors should be considered when interpreting a BMI number.

"There are a lot of children who have very high amounts of body fat that the body mass index misses," says Dr. Ellis. "Just because you have a normal body mass index doesn't necessarily mean you have a normal fat-to-lean weight distribution." He says that the child's family history, ethnicity, maturity level, physical activity level, age and gender can all play roles in determining a child's body composition.

Why the need for an indicator of body fat in children?

The number of obese people in the United States has grown into a `super-sized' national health concern that is not limited to adults. According to data from the National Health and Nutrition Examination Survey (NHANES), the number of overweight children and adolescents has doubled over the last two decades.

Dr. Ellis cites two issues that, based on the available evidence, seem to be the culprits behind the obesity problem in children. The first involves dietary sources. "What is happening is that there are more and more prepared foods, whether it be fast foods or prepared foods at the grocery store. We don't have much control over what goes into those prepared foods, which tend to have a higher percentage of fat content," he says.

The second issue is a lack of physical activity. "If you look at the physical activity levels between now and 20 or 30 years ago, children are much less active today," he says. "So, they are taking in more calories and burning less fat."

Dr. Ellis says there are simple strategies parents can use to encourage their children toward healthy eating and exercise. This may include reminding the child to get exercise by riding a bike, jumping rope or participating in sports. Parents can also help their children understand that fruits and vegetables are healthy choices, he says.

The new pediatric growth charts total 16, eight for boys and eight for girls. In addition to the two new BMI charts, 14 other charts have been revised from previous versions. Pediatric growth charts have been used by health care professionals to assess a child's development since 1977.

The U.S. Department of Health and Human Services reports that the revised pediatric growth charts more accurately reflect the nation's cultural and racial diversity and track children and young people through age 20. The charts for infants have improved significantly thanks to new data and better statistical procedures.

During the National Nutrition Summit, organized by the U.S. Department of Health and Human Services and the U.S. Department of Agriculture, nutrition leaders also unveiled new dietary guidelines for Americans. In addition, Health and Human Services Secretary Donna E. Shalala and Surgeon General David Satcher announced that a workshop is planned for this fall to develop a strategy for addressing the country's weight problems.

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©2006 Texas Medical Center

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