BMI-for-Age as a Screening Measure

The American Academy of Pediatrics Clinical Practice Guideline for the Evaluation and Treatment of Children and Adolescents With Obesity (CPG) and the Bright Futures Guidelines recommend that pediatricians and other pediatric health care providers measure height and weight, calculate BMI, and assess BMI percentile using BMI-for-age growth charts at least annually for all children and teens. BMI-for-age screening provides an opportunity for health care providers to talk with patients and their families about children’s growth.

There are other advantages to using BMI-for-age to screen for underweight, healthy weight, overweight, obesity, and severe obesity in children and teens:

  • BMI-for-age is a continuous measure that can be used for all children and teens aged 2 to 20 years.
  • BMI-for-age can be plotted on growth charts. Percentile curves on the CDC growth charts indicate the relative position of the child’s BMI to children of the same sex and age from the reference population used to create the growth charts.
Child BMI categories and their corresponding sex- and age-specific BMI percentile ranges are shown in the following table:
BMI Category BMI Range
Underweight < 5th percentile
Healthy Weight 5th to < 85th percentile
Overweight 85th to < 95th percentile
Obesity ≥ 95th percentile
Severe Obesity ≥ 120% of the 95th percentile or ≥ 35 kg/m2

Remember: Because children are growing, their BMI values need to be expressed relative to other children of the same sex and age. These values are known as BMI percentiles.

An expanded definition of severe obesity is used by the AAP CPG:

  • Class 2 Obesity: BMI ≥ 120% to < 140% of the 95th percentile or BMI ≥ 35 to < 40 kg/m2
  • Class 3 Obesity: BMI ≥ 140% of the 95th percentile or BMI ≥ 40 kg/m2
BMI-for-Age as a Screening Measure—Test Your Knowledge
  1. According to the AAP and the Bright Futures Guidelines, which of the following should pediatricians and other pediatric health care providers do at least annually for all children and teens?

  2. In children and teens, obesity is defined as a BMI that is greater than or equal to the 95th percentile for age and sex.

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