Differences in Methodology
Different approaches were used to construct the 2000 CDC and 2006 WHO growth charts for children from birth up to 2 years and include differences in the
- Data sources.
- Type and frequency of data collection.
- Sample sizes.
- Exclusion criteria.
- Breastfeeding rates among infants in the sample.
- Use of cross-sectional data to construct the CDC charts versus longitudinal data to construct the WHO growth charts.
|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)|
||Multicenter 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])||
|Infant feeding||50% ever breastfed
33% breastfed at 3 mos