Measuring Growth for Children and Adolescents

Body mass index (BMI), an indirect measure of body fat based on height and weight, has traditionally been used in the screening and assessment of overweight and obesity and is independent of age and sex when used with adults.

In the pediatric population, both age and sex are important considerations since body composition changes as children grow and can differ depending on their sex and maturity. In the year 2000, the Centers for Disease Control and Prevention published revised growth charts for "assessing the size and growth patterns of infants, children and adolescents" in the United States. The CDC's growth charts, intended for use in children and adolescents ages 2 to 20 years old, include BMI-for-age, Weight-for-age and Stature-for-age.

These growth charts aid in tracking a child or adolescent's growth over time and are not meant to be used as a diagnostic tool. BMI is evaluated in relation to percentile cutoffs, which were determined by an expert committee based on nationally representative data from 1963 to 1980. According to the CDC, pediatric overweight and obesity are defined as a BMI-for-age "at the 85th and 95th percentiles or greater."

Since the development of the CDC growth charts, there has been an increasing trend of children with severe obesity in the United States, which is "defined as a BMI greater than or equal to 120% of the 95th percentile on BMI-for-Age growth charts."

In December 2022, the CDC released "Extended BMI-for-Age Growth Charts" based on population data from 1988 to 2016 and an evaluation of BMI metrics for monitoring weight status. This set of growth charts, which also are sex-specific and intended for children and adolescents 2 to 20 years old, includes four additional percentile curves above the 95th percentile, and each chart extends beyond a BMI of 37 kg/m² for plotting a BMI up to 60 kg/m².

These new growth charts are expected to assist practitioners in clinical and research settings with the monitoring of weight status and the assessment of an obesity intervention's effectiveness when working with pediatric patients who have a BMI value that is defined as being extremely high.

Although more research is needed in measuring health outcomes of pediatric weight management interventions, multicomponent nutrition interventions that have included a registered dietitian nutritionist (or international equivalent) have been more effective than those without. RDNs play an important role in both helping to prevent pediatric overweight and obesity, as well as in their treatment. Screening and identifying youth over the age of 2 who are at risk of overweight or obesity can lead to early interventions and therefore decrease the potential for diet-related chronic diseases in the future.

References:

• Mullen CM, Shield J. Academy of Nutrition and Dietetics Pocket Guide to Pediatric Weight Management, 2nd ed. 2018.
• Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC growth charts for the United States: Methods and development. National Center for Health Statistics. Vital Health Stat. 11(246). 2002.
• Centers for Disease Control and Prevention, National Center for Health Statistics. CDC growth charts: United States. May 30, 2000. Accessed March 22, 2022.
• Hoelscher DM, Brann LS, O'Brien S, et al. Prevention of Pediatric Overweight and Obesity: Position of the Academy of Nutrition and Dietetics Based on an Umbrella Review of Systematic Reviews. J Acad Nutr Diet. 2022;122(2):410-423.
• Kirk S, Ogata B, Wichert E, et al. Treatment of Pediatric Overweight and Obesity: Position of the Academy of Nutrition and Dietetics Based on an Umbrella Review of Systematic Reviews. J Acad Nutr Diet. 2022;122(4):848-861.
• Centers for Disease Control and Prevention, Division of Nutrition, Physical Activity, and Obesity. Growth Chart Training: 2022 CDC Extended BMI-for-Age Growth Charts for Children and Adolescents with Severe Obesity. Accessed February 9, 2023.
• Hales CM, Freedman DS, Akinbami L, Wei R, Ogden CL. Evaluation of alternative body mass index (BMI) metrics to monitor weight status in children and adolescents with extremely high BMI using CDC BMI-for-age growth charts. National Center for Health Statistics. Vital Health Stat 2(197). 2022. DOI: https://dx.doi.org/10.15620/cdc:121711.