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CHICAGO -- Clinicians have been urged to relay on BMI to determine whether or not a child is obese, but there may be as many drawbacks as benefits to this type of screening -- as even the "pro" advocate conceded during a debate held here at the .

Joseph Thompson, MD, president and CEO of the Arkansas Center for Health Improvement in Little Rock, Ark., and Stephen Cook, MD, of the University of Rochester in Rochester N.Y., traded thoughts on using BMI as a method to screen children for obesity, especially in light of the recent U.S. Preventive Services Task Force recommendation to screen for obesity in children.

Thompson, taking the "pro" side of the debate, called it "a pretty strong recommendation of BMI as a screening tool for all children in the U.S."

But he acknowledged that BMI has important limitations, and noted that a diagnosis of obesity -- by whatever method -- should not be the end of pediatricians' probing of a child's health status.

Prior to the USPSTF recommendation statement, Thompson, the former Arkansas Surgeon General for 10 years, oversaw a program where Arkansas schools measured children's BMI at school and sent a "health report" home to the parents.

"The battle with obesity is going to be won in the communities, families and schools," he said.

Taking the "con" position, Cook pointed out that BMI-z scores are a poor indicator of adiposity compared to indicators such as skinfold thickness.

"There is no good consensus about what is the abnormal amount of body fat in a child," Cook said. "We have to understand what else goes into it -- it's not just a number."

In addition, Cook argued that parents often do not understand measures such as BMI, and cited surveys that showed most parents feel even their overweight kids are "about the right weight." He said that "respect for autonomy" is important because the parents need to be part of this.

"It's a blunt instrument -- calling every child with a high BMI overweight or obese is like saying every patient with a tumor has cancer," Cook argued.

Thompson conceded that "this is not a perfect test," but that parents often have trouble accepting their children are overweight or obese if they are overweight or obese themselves.

"I'm not okay putting my head in the sand, pretending this issue doesn't exist and we don't have to take action," he said.

Instead of BMI, Cook recommended a different method of communicating levels of severe obesity, such as "20% or 30% over a healthy range," that might be more understandable to parents, who don't always understand growth curves.

He added that the Edmonton Obesity Staging System for adults shows an alternate way of looking at the problem. Not only does it address weight, but medical, mental and functional problems in the patient. A similar tool has been proposed for pediatric use.

After the initial back-and-forth, clinicians in the audience were allowed to ask questions. One wondered if sharing BMI with children increases eating disorder behavior.

Thompson said that comorbidity with obesity and mental health issues is a cause/effect that is "difficult to disentangle," but "nobody has published anything that says a measure of BMI causes an eating disorder."

Cook and Thompson went on to address the continued misperceptions about obesity and BMI in children. Cook said that "to say high BMI and high percent body fat is obesity is probably a disservice. It's discouraging to hear obesity continually listed as a lifestyle condition, as obesity does not have one phenotype."

Thompson also pointed out that there are a subset of kids where "obesity is a marker for an underlying condition" and "an indicator to look for other issues," but that clinicians too often "stop short" and fail to look for other issues in their obese patients.

"We may have done the area of clinical care a disservice by having obesity classified as a disease," he said.

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