Defining obesity in children and adolescents: clinical approaches

For clinical utility, obesity should be defined as a condition of excess adipose tissue associated with adverse health outcomes. Based on a number of criteria, body mass index (BMI) (weight/height) is the most appropriate measure for clinical assessment of adiposity in children and adolescents. However, sufficient information regarding associations between adiposity and current or future morbidity is lacking. Available data suggest a definition of obesity based on adiposity alone would perform poorly as a clinical screening test for adverse health outcomes. In addition, labeling and attempted weight control therapy may produce more harm than benefit. Therefore, until better information regarding the risks of adiposity and risks of treatment are available, recommendations for weight control therapy should be focused primarily on those children and adolescents who currently manifest adiposity-related morbidity, those with a BMI above the 95th percentile, or those above the 85th percentile who perceive their adiposity to be a significant psychosocial problem. To produce a clinically useful definition of obesity, longitudinal data should be used to determine the sensitivities, specificities, and predictive values of comparative measures of childhood and adolescent adiposity for predicting current and future morbidity, and to evaluate the utilities of including characteristics such as age, age of adiposity rebound, persistence of increased adiposity, family adiposity, family morbidities, and fat distribution to improve predictive values and minimize misclassification. Weight control research should attempt to identify patient characteristics that predict long-term treatment success, treatment failure, and treatment side effects.