A study published in the journal JAMA Pediatrics says that the conventional way of measuring adolescent obesity is inadequate. The United States is experiencing an obesity epidemic and an alarming rise in rates of diabetes. And because the two phenomena are related and Type 2 diabetes has been occurring at ever-younger ages, it’s crucial for health professionals to have reliable data on obesity in young people.
The standard way of measuring obesity has been BMI, or body-mass index, which is weight in kilograms divided by height in meters squared. It works quite well for adults, but not so much for children. The authors of the study used three calculations to compare BMI to other ways of measuring obesity. They found that the best overall body fat index to use in youngsters ages 8–17 years is TMI, or tri-ponderal mass index, which is mass divided by height cubed. They reported that adolescents are inaccurately diagnosed as overweight 19.4 percent of the time and that BMI is especially inaccurate in boys. A main reason for the problem, the researchers said, is that the math used to calculate the relationship between body weight and height is more complex in young people than it is in adults, especially during periods of rapid growth.
Courtesy of the University of Alabama at Birmingham (UAB).
The findings of the new study are especially important, according to lead author Courtney M. Peterson, PhD, because “many school districts [send] home report cards labeling adolescents as overweight…and children and adolescents tend to be more vulnerable to weight bias and fat shaming.”