Body mass index (bmi) for children and adolescents

Pediatrics 2020

Body Mass Index (BMI) for children and adolescents

BMI is used differently in children than in adults at Children and adolescents the body mass index is used to assess underweight, overweight and risk of being overweight. Children’s physical form changes over the years as they grow. Girls and boys also differ in their body fatness when they mature. For this reason, the BMI for children, also known as the BMI for children and adolescents, is sometimes also called "BMI-for-age" designated. BMI-for-Age is shown on gender-specific growth charts. These diagrams are used for children and adolescents aged 2 to 20 years. For the CDC 2000 Growth Tables and more information, visit the CDC’s National Center for Health Statistics.

Each of the gender-specific CDC BMI-for-Age charts contains a series of curved lines that show specific percentiles. Healthcare professionals use the following percentile cutoff points to identify underweight and overweight in children.

underweight

BMI-for-age 95th percentile

The BMI decreases in the pre-school years and then increases into adulthood. The percentile curves show this growth pattern.

What does it mean when my child is in the 60th percentile? The 60th percentile means, that 60% have a lower BMI compared to children of the same sex and age.

Example: Let’s look at the BMI for a boy as he grows. As his BMI changes, he remains at the 95th percentile BMI for old age.

Age	BMI	percentile
2 years	19.3	95
4 years	17.8	95
9 years	21.0	95
13 years old	25.1	95

We see the boy’s BMI decrease during his preschool years and increase with age.

Why is BMI-for-age a useful tool? BMI-for-Age is used for children and adolescents due to their growth rate and development. It is a useful tool because:

BMI-for-Age provides a reference for adolescents who can be used beyond puberty.
BMI for age at Children and Adolescents compares well with laboratory measurements of body fat.
BMI-for-Age can be used to track height throughout life.

Source: Centers for Disease Control and Prevention (www.cdc.gov)

For more information, please visit the Diet and Child Health Channels.