Mercedes de Onis
The WHO holds copyright of the WHO Child Growth Standards.
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The growth charts presented in this Annex are a subset of the WHO Child Growth Standards [2, 3] , which are based on an international sample of healthy breastfed infants and young children [4] .
Construction of the WHO Child Growth Standards
The origin of the WHO Child Growth Standards dates back to the early 1990s, when the WHO conducted a comprehensive review of anthropo- metric references. This review showed that the growth pattern of healthy breastfed infants devi- ated significantly from the National Center for Health Statistics/WHO international reference [5] . In particular, the reference was inadequate for assessing the growth pattern of healthy breast- fed infants. The expert group recommended the development of new standards, adopting a novel approach that would describe how children should grow when free of disease and when their care follows healthy practices such as breastfeed- ing and nonsmoking [5] . This approach would permit the development of a standard as opposed to a reference merely describing how children grew in a particular place and time. Although standards and references both serve as a basis for comparison, each permits a different interpreta- tion. Since a standard defines how children should grow, deviations from the pattern it de- scribes are evidence of abnormal growth. A refer- ence, on the other hand, does not provide as sound a basis for such value judgments, although, in practice, references often are mistakenly used as standards.
Following a resolution from the World Health Assembly in 1994 endorsing these recommenda- tions, the WHO Multicentre Growth Reference Study (MGRS) [4] was launched in 1997 to collect primary growth data that would allow the con- struction of new growth charts consistent with
‘best’ health practices.
The goal of the MGRS was to describe the growth of healthy children. The MGRS was a population-based study conducted in 6 countries from diverse geographical regions: Brazil, Gha- na, India, Norway, Oman and the USA [4] . The study combined a longitudinal follow-up from birth to 24 months with a cross-sectional compo- nent of children aged 18–71 months. In the longi- tudinal component, mothers and newborns were enrolled at birth and visited at home a total of 21 times at weeks 1, 2, 4 and 6, monthly from 2–12 months, and bimonthly in the second year.
The study populations lived in socioeconomic conditions favorable to growth. The individual inclusion criteria were: no known health or envi- ronmental constraints on growth; mothers will- ing to follow MGRS feeding recommendations (i.e. exclusive or predominant breastfeeding for at least 4 months, introduction of complementary foods by 6 months of age, and continued breast- feeding to at least 12 months of age); no maternal smoking before and after delivery; single term birth; and absence of significant morbidity. Rig- orously standardized methods of data collection and procedures for data management across sites yielded high-quality data [2, 3] .
The length of children was strikingly similar among the 6 sites, with only about 3% of variabil- ity in length being due to intersite differences compared with 70% for individuals within sites [6] . The striking similarity in growth during ear- ly childhood across human populations means either a recent common origin, as some suggest [7] , or a strong selective advantage associated with the current pattern of growth and develop- ment across human environments. The data from all sites were pooled to construct the standards, following state-of-the-art statistical methodolo- gies [2] .
This Annex presents growth charts for weight-for-age, length/height-for-age, weight- for-length/height, BMI-for-age and head cir- cumference-for-age, in percentile values, for boys and girls aged 0–60 months. The full set
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of tables and charts is presented on the WHO website (www.who.int/childgrowth/en), together with tools such as software and training materi- als that facilitate their clinical application. The disjunction observed at 24 months in the length-/
height-based charts represents the change from measuring recumbent length to standing height.
Standards for other anthropometric variables (i.e. mid-upper-arm circumference, and triceps and subscapular skinfolds) are also available on the website.
Implications of Adopting the WHO Child Growth Standards
The scrutiny that the WHO Standards have un- dergone is without precedent in the history of de- veloping and applying growth assessment tools.
Governments set up committees to scrutinize the new standards before deciding to adopt them, and professional groups conducted thorough ex- aminations of the standards. The detailed evalua- tion allowed assessing the impact of the new stan- dards and documenting their robustness and benefits for child health programs. Since their re- lease in 2006, the WHO Growth Standards have been widely implemented globally [8] . Reasons for adoption include: (1) providing a more reli- able tool for assessing growth that is consistent with the Global Strategy for Infant and Young Child Feeding; (2) protecting and promoting breastfeeding; (3) allowing monitoring of malnu- trition’s double burden, i.e. stunting and over- weight; (4) promoting healthy growth and pro- tecting the right of children to reach their full ge- netic potential; and (5) harmonizing national growth assessment systems. In adopting the WHO Growth Standards, countries have harmo- nized best practices in child growth assessment and established the breastfed infant as the norm against which to assess compliance with chil- dren’s right to achieve their full genetic growth potential.
The detailed examination of the WHO Growth Standards by technical and scientific groups has provided a unique opportunity to val- idate their robustness and to improve our under- standing of their broad benefits:
• The WHO Standards identify more children as severely wasted [9] ; besides being more ac- curate in predicting mortality risk [10–12] , use of the WHO Standards results in shorter dura- tion of treatment, higher rates of recovery and fewer deaths, and it reduced loss to follow-up or the need for inpatient care [13]
• The WHO Standards confirm the dissimilar growth patterns of breastfed and formula-fed infants, and provide an improved tool for cor- rectly assessing adequacy of growth in breast- fed infants [14–16] ; they thereby considerably reduce the risk of unnecessary supplementa- tion or cessation of breastfeeding, which are major sources of morbidity and mortality in poor-hygiene settings
• In addition to confirming the importance of the first 2 years of life as a window of opportu- nity for promoting growth, the WHO Stan- dards demonstrate that intrauterine retarda- tion in linear growth is more prevalent than previously thought [17] , making a strong case for the need for interventions to start early in pregnancy and before
• Another important feature of the WHO Stan- dards is that they demonstrate that undernu- trition during the first 6 months of life is a con- siderably more serious problem than previ- ously detected [16–18] , thereby reconciling the rates of undernutrition observed for young infants and the prevalence of low birth weight and early abandonment of exclusive breast- feeding
• The WHO Standards also improve early de- tection of excess weight gain among infants and young children [19, 20] , showing that obesity often begins in early childhood, as should measures to tackle this global ‘time bomb’
Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 278–294 DOI: 10.1159/000360352
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• Last but not least, the WHO Standards are an important means of ensuring the right of all children to be healthy and to achieve their full growth potential; they provide sound scientif- ic evidence that, on average, young children everywhere experience similar growth pat- terns when their health and nutritional needs are met. For this reason the WHO Standards can be used to assess compliance with the UN Convention on the Rights of the Child, which recognizes the duties and obligations to chil- dren that cannot be met without attention to normal human development
Conclusions
The WHO Child Growth Standards were derived from children who were raised in environments that minimized constraints on growth such as poor diets and infection. In addition, their mothers followed healthy practices such as breastfeeding their children and not smoking during and after pregnancy. The standards depict normal human growth under optimal environmental conditions
and can be used to assess children everywhere, re- gardless of ethnicity, socioeconomic status and type of feeding. They also demonstrate that healthy children from around the world who are raised in healthy environments and follow recommended feeding practices have strikingly similar patterns of growth. The International Pediatric Association has officially endorsed the use of the WHO Stan- dards, describing them as ‘an effective tool for de- tecting both undernutrition and obesity’ [21] .
Early recognition of growth problems, such as faltering growth and excessive weight gain rela- tive to linear growth, should become standard clinical practice by:
• routine collection of accurate weight and height measurements to permit monitoring of childhood growth;
• interpretation of anthropometric indices such as height-for-age and BMI-for-age based on the WHO Child Growth Standards, and • early intervention after changes to growth pat-
terns (e.g. upward or downward crossing of percentiles) have been observed to provide parents and caregivers with appropriate guid- ance and support.
8 de Onis M, Onyango A, Borghi E, Siyam A, Blửssner M, Lutter CK; WHO Multi- centre Growth Reference Study Group:
Worldwide implementation of the WHO Child Growth Standards. Public Health Nutr 2012; 15: 1603–1610.
9 Dale NM, Grais RF, Minetti A, Miettola J, Barengo NC: Comparison of the new World Health Organization growth standards and the National Center for Health Statistics growth reference re- garding mortality of malnourished chil- dren treated in a 2006 nutrition pro- gram in Niger. Arch Pediatr Adolesc Med 2009; 163: 126–130.
References
1 Physical status: the use and interpreta- tion of anthropometry. Report of a WHO Expert Committee. World Health Organ Tech Rep Ser 1995; 854: 1–452.
2 WHO Multicentre Growth Reference Study Group: WHO Child Growth Stan- dards: length/height-for-age, weight- for-age, weight-for-length, weight-for- height and body mass index-for-age:
methods and development. Geneva, WHO, 2006.
3 WHO Multicentre Growth Reference Study Group: WHO Child Growth Stan- dards based on length/height, weight and age. Acta Paediatr Suppl 2006; 450:
76–85.
4 de Onis M, Garza C, Victora CG, et al (eds): WHO Multicentre Growth Refer- ence Study (MGRS): rationale, planning and implementation. Food Nutr Bull 2004; 25(suppl 1):S3–S84.
5 Garza C, de Onis M; WHO Multicentre Growth Reference Study Group: Ratio- nale for developing a new international growth reference. Food Nutr Bull 2004;
25(suppl 1):S5–S14.
6 WHO Multicentre Growth Reference Study Group: Assessment of differences in linear growth among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl 2006; 450:
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7 Rosenberg NA, Pritchard JK, Weber JL, et al: Genetic structure of human popu- lations. Science 2002; 298: 2381–2385.
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Shepherd S, Grais RF: Prognostic accu- racy of WHO growth standards to pre- dict mortality in a large-scale nutritional program in Niger. PLoS Med 2009; 6:
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11 Vesel L, Bahl R, Martines J, Penny M, Bhandari N, Kirkwood BR; WHO Im- munization-Linked Vitamin A Supple- mentation Study Group: Use of new World Health Organization child growth standards to assess how infant malnutri- tion relates to breastfeeding and mortal- ity. Bull World Health Organ 2010; 88:
39–48.
12 O’Neill S, Fitzgerald A, Briend A, van den Broeck J: Child mortality as predict- ed by nutritional status and recent weight velocity in children under two in rural Africa. J Nutr 2012; 142: 520–525.
13 Isanaka S, Villamor E, Shepherd S, Grais RF: Assessing the impact of the intro- duction of the World Health Organiza- tion growth standards and weight-for- height z-score criterion on the response to treatment of severe acute malnutri-
tion in children: secondary data analy- sis. Pediatrics 2009; 123:e54–e59.
14 Saha KK, Frongillo EA, Alam DS, Arifeen SE, Persson LA, Rasmussen KM:
Use of the new World Health Organiza- tion child growth standards to describe longitudinal growth of breastfed rural Bangladeshi infants and young children.
Food Nutr Bull 2009; 30: 137–144.
15 Bois C, Servolin J, Guillermot G: Usage comparé des courbes de l’Organisation mondiale de la santé et des courbes franỗaises dans le suivi de la croissance pondérale des jeunes nourrissons. Arch Pediatr 2010; 17: 1035–1041.
16 de Onis M, Onyango AW, Borghi E, Gar- za C, Yang H; WHO Multicentre Growth Reference Study Group: Comparison of the WHO Child Growth Standards and the NCHS/WHO international growth reference: implications for child health programmes. Public Health Nutr 2006;
9: 942–947.
17 Victora CG, de Onis M, Hallal PC, Blửss- ner M, Shrimpton R: Worldwide timing of growth faltering: revisiting implica-
tions for interventions using the World Health Organization growth standards.
Pediatrics 2010; 125:e473–e480.
18 Kerac M, Blencowe H, Grijalva-Eternod C, McGrath M, Shoham J, Cole TJ, Seal A: Prevalence of wasting among under 6-month-old infants in developing countries and implications of new case definitions using WHO growth stan- dards: a secondary data analysis. Arch Dis Child 2011; 96: 1008–1013.
19 van Dijk CE, Innis SM: Growth-curve standards and the assessment of early excess weight gain in infancy. Pediatrics 2009; 123: 102–108.
20 Maalouf-Manasseh Z, Metallinos-Kat- saras E, Dewey KG: Obesity in preschool children is more prevalent and identi- fied at a younger age when WHO growth charts are used compared with CDC charts. J Nutr 2011; 141: 1154–1158.
21 International Pediatric Association En- dorsement: the new WHO Growth Stan- dards for infants and young children.
2006. http://www.who.int/childgrowth/
Endorsement_IPA.pdf.
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Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 278–294 DOI: 10.1159/000360352
4 Annexes
Key Words
Growth assessment ã Growth references ã Anthropometry ã Interpretation
Key Messages
• Growth charts are essential tools for the interpreta- tion of growth measurements in children
• The CDC and Euro Growth charts are growth refer- ences that describe the growth of populations of children as they exist at a given time in a given loca- tion
• Growth standards (e.g. WHO Child Growth Stan- dards) describe the growth of children who live in favorable circumstances, receive optimal nutrition and show desirable growth characteristics • Anthropometric measurements need to use proper
techniques. Measurements of recumbent length must be interpreted against charts of recumbent length, and measurements of standing height must be interpreted against charts of standing height
© 2015 S. Karger AG, Basel
Introduction
Growth assessment is an integral part of child- hood health monitoring. For interpretation, growth measurements must be compared with appropriate norms. Such norms are provided by growth references which describe the growth of
children who are living in a defined geographic area and are deemed healthy. The relative position of a child undergoing assessment in comparison with reference data determines whether the child’s growth is judged normal or abnormal. Widely used growth references are the CDC Growth Charts [1] and the Euro Growth Charts [2] . Both were released in 2000. These charts describe the growth of children living in the USA and in Eu- rope, respectively. The WHO Growth Standards [3, 4] , on the other hand, describe the growth of children worldwide; for these standards, data were obtained in Norway, the USA, Brazil, Ghana, Oman and India from children living under ‘ideal’
circumstances with nonsmoking mothers and from infants receiving ‘optimal nutrition’ (pre- dominantly breast milk for the first 6 months), and thus they illustrate what ‘normal growth’ is under optimal environmental conditions.
When growth has to be assessed on the basis of a single measurement, its interpretation has to rely solely on the relative position of the mea- sured value on the growth reference chart. The accuracy of growth assessment is greatly im- proved if two or more measurements are per- formed at different times. This not only mini- mizes the impact of inherent measurement er- rors, it also permits the assessment of time trends and thus strengthens the assessment of a child’s growth vis-à-vis the growth reference chart.
Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 295–307 DOI: 10.1159/000360353