Should Infants and Toddlers Be Measured for Obesity?

April 27, 2006 — -- As part of an effort to better monitor the health of children everywhere, the World Health Organization has announced standardized measurement tests today to assess children's growth, nutritional status and motor development.

In many parts of the world, children are malnourished, and the standards will help health-care workers to better understand when a child's needs are not being met.

However, in the United States -- a country where children are far more likely to be overnourished -- the new WHO standards raise an interesting issue: whether health-care workers should measure infants, toddlers and young children for their body mass index -- a quick height-weight ratio measurement test to see whether a person is overweight or obese.

The new guidelines include a BMI test for children from birth to five years. Does testing children that young really help, though, especially when it comes to obesity?

(To find out your BMI, go here: CDC Body Mass Index page.)

Doctors' opinions are mixed. That's because there are other, more specific ways to see whether a young child is overweight, said Sandra Hassink, a pediatrician on the American Academy of Pediatrics' Task Force on Obesity.

"It is only one piece of data that a physician needs to put into context," Hassink said.

BMI is a good way to determine the average body fat in a population, but it does not directly measure fat so it shouldn't be used for individuals, said Dr. David Heber of the Center for Human Nutrition at the University of California Los Angeles.

Specifically, it doesn't take into account factors like muscle mass or muscle loss that can contribute to a person's weight, he said.

"[BMI] is misleading in many adults and kids," Heber said.

The U.S. Centers for Disease Control and Prevention has its own standard BMI chart for children older than 2, and Hassink said most pediatricians were familiar with it.

Years ago, a high BMI was linked to an increased risk of disease or death, which made it useful for adults, but "it's a little less clear especially in the first two years of life what [BMI] means."