Anthropometric Indices: Definitions and Categories

What to know

Weight and height (also referred to as stature) are commonly used to assess the growth of children and adolescents aged 2 to 20 years. An anthropometric index occurs when age is combined with weight, height, or body mass index (BMI). The CDC Growth Charts for children and adolescents reflect three anthropometric indices that are sex- and age-specific.

Health care provider measuring a boy's height.

Anthropometric indices definitions

Stature-for-age describes linear growth relative to age. Stature- or length-for-age is used to define how short or tall the child or adolescent is at the time.

Weight-for-age reflects body weight relative to age and might be influenced by recent changes in health or nutrition. Weight-for-age is not used to classify children and adolescents as having underweight or overweight. However, the index can help explain changes in BMI-for-age in some children and adolescents.

BMI-for-age reflects BMI relative to age. BMI is a measure of weight adjusted for height. In children and adolescents, BMI-for-age percentiles are used to define BMI categories.

Child BMI categories

Percentiles indicate what percent of a reference population an individual would equal or exceed. Using sex- and age-specific percentiles to define BMI categories in children is important because they are still growing.

The definitions of BMI categories are:

BMI Range BMI Category
< 5th Percentile Underweight
5th Percentile to < 85th Percentile Healthy Weight
≥ 85th Percentile to < 95th Percentile Overweight
≥ 95th Percentile Obesity
≥ 120% of the 95th Percentile or ≥ 35 kg/m2 Severe Obesity

Test your knowledge

  1. BMI-for-age is an anthropometric index that reflects body mass index relative to age.
    1. True
    2. False
  2. Percentiles are used to indicate the position of a person by indicating what percent of the reference population the person would equal or exceed.
    1. True
    2. False

See answers.A

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Content Source:
National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP)
  1. Question 1: True. Question 2: True. Using sex- and age-specific percentiles to define BMI and stature categories in children and adolescents is particularly important because they are still growing.