Child obesity interventions: Is change in BMI a good measure of success?

Body mass index (BMI) or a change in BMI is often the sole measure used to evaluate whether an intervention intended to combat childhood obesity is effective. But a new study clearly shows that an intervention can have beneficial effects on other health outcomes, such as cardiovascular fitness, regardless of its effect on BMI. Focusing on a single factor like the degree of BMI change is restrictive and can overlook other important outcomes, according to an article published in Childhood Obesity.

Maria Kolotourou and a team of authors involved in the Mind, Exercise, Nutrition...Do It! (MEND) trial from University of London, University College London, and Mytime MEND gathered data from a group of obese children before they participated in the MEND childhood obesity intervention and again at 6- and 12-month follow-up intervals. The researchers measured BMI, degree of change in BMI, waist circumference, cardiovascular fitness, physical activity, sedentary behaviors, and self-esteem.

In the article "Is BMI Alone a Sufficient Outcome to Evaluate Interventions for Child Obesity?" the authors report improvements, in several of the parameters measured, independent of whether a child's BMI decreased, increased, or remained the same.

"Good interventions aimed at helping overweight children lose weight should be equally directed at helping them to find health. This article suggests that health benefits may be seen independent of weight change, per se, and we are thus better served by evaluation strategies that encompass an array of relevant and important measures," says David L. Katz, MD, MPH, Editor-in-Chief of Childhood Obesity and Director of Yale University's Prevention Research Center.