Comparing Growth Chart Methodologies

What to know

The World Health Organization (WHO) child growth standards describe how healthy infants and young children worldwide should grow under optimal environmental and health conditions. CDC growth charts are growth references that describe the growth of children in the United States. This page describes the similarities and differences between the methodologies.

Mother holding an infant while grandmother looks on.

WHO growth standards

WHO child growth standards represent how healthy infants and young children should grow under optimal environmental and health conditions. The study that informed the growth standards creation included healthy infants who were well-fed according to international recommendations.

The WHO growth standards:

  • Are an international standard for infants and young children.
  • Provide a standard against which to compare all infants.
  • Help clinicians identify and address environmental conditions that might negatively affect growth.
  • Are recommended for use in U.S. clinical settings for children from birth to 2 years.

CDC growth charts

The CDC growth charts are a growth reference. They describe the growth of children in the United States during a particular time period.

CDC growth charts:

  • Indicate how children grew in the United States from 1963 to 1994.
  • Do not imply that the represented growth pattern is healthy.

Methodology differences

Different approaches were used to make the 2000 CDC growth charts and the 2006 WHO growth standards for children from birth to 2 years. These differences are outlined in the table below.

Comparison of sample populations used to create the CDC and WHO growth curves for children younger than aged 2 years
CDC Growth Reference (2000) WHO Growth Standard (2006)
Data sources
  • National vital statistics (birthweight)
  • Missouri and Wisconsin vital statistics (birth length)
  • Pediatric Nutrition Surveillance System
    (length, 0.1 to <5 mos)
  • NHANES I (1971-74): 12-23 mos
  • NHANES II (1976-80): 6-23 mos
  • NHANES III (1988-94): 2-23 mos
 Multicentre Growth Reference Study (longitudinal component)
Type and frequency of  data collection Cross-sectional data on weight and length starting at age 2 mos, with mathematical models used to connect birth weights and lengths to survey data Longitudinal data with measurements of weight and length at birth; 1, 2, 4, 6, and 8 weeks; and 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, and 24 mos
Sample size 4,697 observations for 4,697 distinct children 18,973 observations for 903 distinct children
Exclusion criteria Very low birth weight  (<1,500 g [<3 lbs, 4 oz])
  • Low socioeconomic status
  • Born at altitude >1,550
    m/4,921 f
  • Birth at <37 wks or >42 wks
  • Multiple births
  • Perinatal morbidities
  • Child health conditions known to affect growth
  • Mother smoked during pregnancy or lactation
  • Breastfeeding <12 mos
  • Introduction of complementary foods before age 4 mos or after 6 mos
  • Weight-for-length measurements >3
    standard deviations above or below study median for sex
Infant feeding 50% ever breastfed
33% breastfed at 3 mos
  • 100% ever breastfed
  • 100% predominantly breastfed at 4 mos
  • 100% breastfed at 12 mos
  • Complementary foods introduced at mean age of 5.4 mos

Methodology similarities

The WHO and CDC growth charts had several similarities. Both were developed to replace the 1977 National Center for Health Statistics (NCHS)/WHO growth reference. The NCHS/WHO growth reference was considered the international reference at the time.

Growth curves for both charts were developed using an LMS methodology12 to describe both percentiles and z-scores (standard deviation units). However, there were some differences in the smoothing techniques used to create the growth curves.

Data quality was tightly controlled in both studies. There were precise training procedures and measurement standardization using high-quality anthropometry equipment. In addition, optimal data entry and cleaning techniques were used34.

More information

2000 CDC Growth Charts for the United States: Methods and Development

WHO Child Growth Standards

CDC Growth Charts

Test your knowledge

  1. The WHO growth standards are considered a standard against which to compare all infants and young children because these standards:
    1. Describe how healthy infants and young children should grow under optimal conditions.
    2. Represent the growth of infants and young children under less than optimal conditions.
    3. Are based on data that included infants who stopped breastfeeding at 6 months.
  2. To achieve optimal environmental and health conditions, infants were excluded from the WHO Multicentre Growth Reference Study used to create the WHO growth standards if the infants were:
    1. Born to mothers who smoked during pregnancy or lactation.
    2. Breastfed for less than 12 months.
    3. Introduced to complementary foods before 4 months of age.
    4. All of the above.

See answers.A

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Content Source:
National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP)
  1. Question 1 is A. The WHO growth standards are standards against which to compare all infants and young children because these standards describe how healthy infants and young children should grow under optimal environmental, behavioral, and health conditions. Question 2 is D. All of the above were exclusion criteria.
  1. Cole TJ. The LMS method for constructing normalized growth standards. Eur J Clin Nutr. 1990;44(1):45–60.
  2. Cole TJ, Green PJ. Smoothing reference centile curves: the LMS method and penalized likelihood. Stat Med. 1992;11(10):1305–1319.
  3. de Onis M, Onyango AW, Van den Broeck J, Chumlea WC, Martorell R. Measurement and standardization protocols for anthropometry used in the construction of a new international growth reference. Food Nutr Bull. 2004;25(1 Suppl):S27–S36.
  4. Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC Growth Charts for the United States: methods and development. Vital Health Stat 11. 2002;(246):1–190.