Body Mass Index or BMI
Body Mass Index, or BMI (wt/ht2), provides a guideline based on weight and height to determine underweight and overweight. As children grow, their body mass changes. The interpretation of BMI depends on the child’s age. Additionally, girls and boys differ in their body mass as they mature. Therefore, we plot the BMI-for-age according to sex-specific charts.
How to Interpret BMI for Age in Children and Adolescents
Established cut off points should be used to identify underweight and overweight children and adolescents.
The extremes in BMI-for-age that raise concern in children 2 to 20 years of age
Underweight BMI-for-age <5th percentile
At risk of overweight BMI-for-age >85th percentile
Overweight BMI-for-age >95th percentile
What are the advantages of using BMI-for-age with children from 2 to 20 years?
- BMI-for-age can be used for adolescents beyond puberty.
- BMI in children and adolescents compares well to laboratory measures of body fat.
- BMI is related to health risks.
Sixty percent of children and teens with a BMI-for-age above the 95th percentile have at least one risk factor while 20 percent have two or more risk factors for cardiovascular disease.
Overweight children are likely to become overweight adults. The standards used to identify obesity and overweight in children and adolescents agree with standards used to identify overweight and obesity in adults.