Error processing SSI file

# What Is Body Mass Index (BMI)?

The Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) recommend that health care providers in primary care settings use:

• The 2000 CDC BMI-for-Age Growth Charts to monitor growth of children and teens aged 2 to 20 years in the United States.
• The 2022 CDC Extended BMI-for-Age Growth Charts to plot BMI and monitor growth of children and teens aged 2 to 20 years with very high BMIs (above the 97th percentile for sex and age).

## What Is BMI?

### A measure of weight relative to height

Body Mass Index (BMI) is a calculated measure of body weight in kilograms divided by height in meters squared (Keys et al., 1972).

BMI = weight (kg) / height (m)2

### A screening measure

The AAP and the Bright Futures Guidelines [PDF-245KB] recommend annual BMI screening for children and teens as part of routine pediatric care. BMI is a screening measure used to identify whether a BMI falls into the underweight, healthy weight, overweight, obesity, or severe obesity category. Because children are growing, their BMI values need to be expressed relative to other children of the same sex and age. These are called BMI-for-age percentiles.

### An indirect measure of adiposity

BMI is highly correlated with direct measures of adiposity (body fatness), such as dual energy x-ray absorptiometry (or DEXA). However, BMI is not a direct measure of adiposity, and BMI does not distinguish between fat and fat-free body mass. Compared to direct measures of adiposity, BMI is simpler, less expensive, less invasive, and collected in routine pediatric health care.

What is Body Mass Index - Test Your Knowledge
1. Body mass index (BMI) is a calculated measure of body weight relative to height.

True
False

ANSWER: TRUE – That’s correct. BMI is a calculated measure of body weight in kilograms divided by height in meters squared.

2. BMI percentiles are age- and sex-specific for children and teens. Thus, sex-specific BMI-for-age percentiles are used to screen children and teens for underweight, healthy weight, overweight, obesity, or severe obesity:

True
False

ANSWER: True – That is correct. Because children and teens are growing, their BMIs need to be expressed relative to others of the same sex and age. This is often referred to as sex-specific BMI-for-age percentiles. BMI categories for children and teens are based on BMI-for-age percentiles.

3. Which statement accurately describes BMI?

A. BMI highly correlates with direct measures of body fat.
B. BMI directly measures body fat.

ANSWER: A – That’s correct. BMI does not directly measure body fat nor distinguish between fat and fat-free body mass. However, BMI correlates with direct measures of body fat.