We explain the difference between the World Health Organisation's (WHO) growth chart and that of the Centers for Disease Control and Prevention (CDC) in America.
From the WHO website:
"There are important differences between the WHO and CDC charts that vary by age group, growth indicator, and specific Z-score curve. Differences are particularly important during infancy, which is likely due to differences in study design and characteristics of the sample, such as type of feeding.
"Overall, the CDC charts reflect a heavier, and somewhat shorter, sample than the WHO sample. This results in lower rates of undernutrition (except during the first 6 months of life) and higher rates of overweight and obesity when based on the WHO standards.
"Healthy breast-fed infants track along the WHO standard’s weight-for-age mean Z-score while appearing to falter on the CDC chart from 2 months onward.
"Shorter measurement intervals in the WHO standards result in a better tool for monitoring the rapid and changing rate of growth in early infancy. Their adoption would have important implications for the assessment of lactation performance and the adequacy of infant feeding and would bring coherence between the tools used to assess growth and U.S. national guidelines that recommend breast-feeding as the optimal source of nutrition during infancy."
From the Centers for Disease Control and Prevention (CDC) website:
"Growth charts consist of a series of percentile curves that illustrate the distribution of selected body measurements in children. Pediatric growth charts have been used by pediatricians, nurses, and parents to track the growth of infants, children, and adolescents in the United States since 1977.
CDC recommends that health care providers:
- Use the WHO growth standards to monitor growth for infants and children ages 0 to 2 years of age in the U.S.
- Use the CDC growth charts for children age 2 years and older in the U.S.
"Growth charts are not intended to be used as a sole diagnostic instrument. Instead, growth charts are tools that contribute to forming an overall clinical impression for the child being measured."
Zelda Ackerman, registered dietician:
"The WHO growth charts were launched in 2006. It was compiled after getting data from exclusively breastfed babies from 6 countries in the world so that the data would be able to use worldwide.
"The limitation is that these growth charts are only for birth to 5 years. In 2007 they also brought out some charts for 5-10 years but it is based on old data from 1977, so not the same quality as the birth to 5-year one. The problem that we as dieticians thus have is that the WHO charts only provide complete charts up to 5 years.
"The CDC growth charts were launched in 2000 and is based on American data. These charts have complete data for children up to 20 years.
"In my practice I use growth charts from both the CDC and WHO. Both have their strengths and limitations. The data do correlate closely, so the average mother can really use any one of the 2. When a child does have a weight problem (under or overweight), a dietician will mostly likely use a few different growth charts to assess the child’s growth.
"I do not advise mothers to use the growth chart on the Road to Health chart as this is only weight for age and for boys and girls combined, so this is the only chart that I personally see not much value in when used on its own."