Dr Mercedes de Dr Mercedes de OnisOnis

Department of NutritionDepartment of NutritionWorld Health OrganizationWorld Health OrganizationGeneva, SwitzerlandGeneva, Switzerland

1 year 2 years 3 years 4 years 5 years

WHO Child Growth StandardsImplications for everyday practice

Why?Why?

WHO Child Growth Standards

Milestones in the development of theMilestones in the development of the WHO child growth standardsWHO child growth standards

19911991--19931993 WHO Working Group on Infant GrowthWHO Working Group on Infant Growth

Comprehensive review shows growth patterns of Comprehensive review shows growth patterns of healthy breastfed infants differ from the current healthy breastfed infants differ from the current NCHS/WHO international reference NCHS/WHO international reference

A new growth reference is needed to improve infant A new growth reference is needed to improve infant health managementhealth management

The reference population should reflect health The reference population should reflect health recommendations in view of the frequent use of recommendations in view of the frequent use of references as references as ““standardsstandards””

Mean ZMean Z--scores of healthy breastfed infants scores of healthy breastfed infants relative to the NCHS/WHO referencerelative to the NCHS/WHO reference

Source: An Evaluation of Infant Growth, WHO, 1994

Source: An Evaluation of Infant Growth, WHO, 1994

Milestones in the development of the Milestones in the development of the WHO child growth standardsWHO child growth standards

19931993 WHO Expert CommitteeWHO Expert Committee

Recommends development of a new international Recommends development of a new international growth referencegrowth reference

Based on an international sample of Based on an international sample of ““healthyhealthy”” infantsinfants

19941994 WHA resolution (WHA 47.5)WHA resolution (WHA 47.5)

Endorses need for new referenceEndorses need for new reference

Requests it to be based on breastfed infantsRequests it to be based on breastfed infants

How?How?

WHO Child Growth Standards

A Growth Curve for the A Growth Curve for the 21st Century21st Century

Department of Nutrition World Health Organization

Geneva, Switzerland

The WHO Multicentre The WHO Multicentre Growth Reference Growth Reference

StudyStudy

Approaches for developing growth referencesApproaches for developing growth references

Descriptive approach (existing growth charts):Descriptive approach (existing growth charts):defines growth on the basis of representative samples of defines growth on the basis of representative samples of healthy groups, i.e., without identifiable disease healthy groups, i.e., without identifiable disease

Prescriptive approach (new approach by WHO):Prescriptive approach (new approach by WHO):defines growth on the basis of health and feeding defines growth on the basis of health and feeding practices known to promote optimal growth and selects practices known to promote optimal growth and selects the sample accordinglythe sample accordingly

Optimal NutritionOptimal Nutrition–– Breastfed infantsBreastfed infants–– Appropriate complementary feedingAppropriate complementary feeding

Optimal EnvironmentOptimal Environment–– No microbiological contaminationNo microbiological contamination–– No smokingNo smoking

Optimal Health CareOptimal Health Care–– ImmunizationImmunization–– PediatricPediatric routinesroutines

OptimalGrowth

WHO Growth Reference StudyWHO Growth Reference Study Prescriptive ApproachPrescriptive Approach

Conceptual basis for the selection of the Conceptual basis for the selection of the population population

"What we want is not a higher standard of "What we want is not a higher standard of perfection in a few, but a higher average, perfection in a few, but a higher average, and this can be best produced by the and this can be best produced by the elimination of the lowest of all and a free elimination of the lowest of all and a free intermingling of the rest"intermingling of the rest"

Alfred Alfred RusselRussel Wallace (1900)Wallace (1900)

WHO Child Growth StandardsWHO Child Growth StandardsStudy sampleStudy sample

Six countriesSix countries

<5% stunting, wasting, underweight<5% stunting, wasting, underweight

At least 20% mothers breastfeedingAt least 20% mothers breastfeeding

No health/environmental constraints on growthNo health/environmental constraints on growth

NonNon--smoking mothersmoking mother

Willing to follow feeding recommendationsWilling to follow feeding recommendations

Single, term birthSingle, term birth

No significant morbidityNo significant morbidity

Measurement and Measurement and standardization protocolsstandardization protocols

Rigorous scientific standards are Rigorous scientific standards are applied to a complex crossapplied to a complex cross--cultural cultural fieldfield--based project. based project.

WHO Multicentre Growth Reference Study

Time schedule child anthropometry in Time schedule child anthropometry in longitudinal study (21 visits)longitudinal study (21 visits)

Measurement Time frame Frequency No. of visitsBirth Once 1Weeks 2-8 Bi-weekly 43-12 months Monthly 10

Weight, length, headcircumference

14-24 months Bi-monthly 6

3-12 months Monthly 10Arm circumferenceSkinfold thicknesses 14-24 months Bi-monthly 6

Motor developmentMotor development

Six universal motor Six universal motor development development milestones assessed milestones assessed between 4 and between 4 and

18 18

months of age. months of age.

The WHO Multicentre Growth Reference Study Rationale, Planning & Implementation

Food and Nutrition BulletinVol 25, Suppl no.1 March 2004

ConstructionConstructiongrowth growth

standardsstandardsWHO, Geneva WHO, Geneva

1 year 2 years 3 years 4 years 5 years

WHO Child Growth StandardsWHO Child Growth Standards

Mean length from birth to 24 months for the six MGRS sitesMean length from birth to 24 months for the six MGRS sites

Age (days)

Mea

n of

Len

gth

(cm

)

0 200 400 600

5060

7080

BrazilGhanaIndiaNorwayOmanUSA

WHO Multicentre Growth Reference Study Group. Assessment of linear growth differences among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl 2006;450:56-65.

Length at selected centiles for the pooled sample and the Length at selected centiles for the pooled sample and the sample following the exclusion of Norwaysample following the exclusion of Norway

0 200 400 600

Age (days)

5060

7080

90

Leng

th (c

m)

Pooled P3Pooled P25Pooled P50Pooled P75Pooled P97Exc Norway P3Exc Norway P25Exc Norway P50Exc Norway P75Exc Norway P97

WHO Multicentre Growth Reference Study Group. Assessment of linear growth differences among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl 2006;450:56-65.

Length at selected centiles for the pooled sample and the Length at selected centiles for the pooled sample and the sample following the exclusion of Indiasample following the exclusion of India

0 200 400 600

Age (days)

5060

7080

90

Leng

th (c

m)

Pooled P3Pooled P25Pooled P50Pooled P75Pooled P97Exc India P3Exc India P25Exc India P50Exc India P75Exc India P97

WHO Multicentre Growth Reference Study Group. Assessment of linear growth differences among populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl 2006;450:56-65.

Construction of growth curves Construction of growth curves

The rigorous methods of data collection yielded very high-quality dataset

State-of-art statistical methods applied in a methodical way:

– Detailed examination of 30 existing methods, including types of distributions and smoothing techniques;

– Selection of a software package flexible enough to allow comparative testing of alternative methods and the actual generation of the curves;

– Systematic application of the selected approach to the data to generate models that resulted in the best fit

Ongoing statistical review by external expert panel

WHO Child Growth StandardsWHO Child Growth Standards

Attained growth

Length/height-for-age

Weight-for-age

Weight-for-length/height

Body mass index-for-age

Arm circumference-for-age

Triceps skinfold-for-age

Subscapular skinfold-for-age

Head circumference-for-age

Growth velocity

Weight

Head circumference

Length

April 2007

April 2006

April 2009

WHO Multicentre Growth Reference Study

Motor Development Assessment

WeightWeight--forfor--ageage, 0, 0--6 6 monthsmonths

WHO Child Growth StandardsWHO Child Growth StandardsGrowth velocity

Variables: weight, length, head circumference

Increments: 1-, 2-, 3-, 4-, 6-months

Total of 160 tables!

Software for PC and PDASoftware for PC and PDAPC PDA

Adoption and implementationAdoption and implementation

Standards well received: Standards well received: opportunity to redefine opportunity to redefine and revitalize actions to promote child growth and and revitalize actions to promote child growth and developmentdevelopment

Incorporation of height and BMI to assess Incorporation of height and BMI to assess double burden (stunting and overweight)double burden (stunting and overweight)

> 120 countries adopted and in different phases > 120 countries adopted and in different phases of implementationof implementation

> 30 countries in process of adopting> 30 countries in process of adopting

Implementation WHO Child Growth StandardsImplementation WHO Child Growth StandardsNovember 2009November 2009

!!!!

!

Implementation StatusImplementing

Adoption being discussed

Not being discussed

Status unknown

Motives for adoptionMotives for adoption Improved tool for growth assessmentImproved tool for growth assessmentCoherence with country adoption of IYCF Coherence with country adoption of IYCF

global strategyglobal strategy To monitor double burden of malnutrition To monitor double burden of malnutrition

(stunting and overweight)(stunting and overweight)Harmonizing growth assessment systems Harmonizing growth assessment systems

within within andand between countriesbetween countries

Training of trainers regional workshopsTraining of trainers regional workshops

EMRO: El Cairo, February 2007

AMRO (South America): Bolivia, April 2007

AMRO (Central America): Nicaragua, May 2007

AFRO: Ethiopia, June 2007

WPRO: Malaysia, September 2007

SEARO: Indonesia, October 2007

Did we Did we achieved achieved what we what we

aimed to?aimed to?

WHO Child Growth Standards

Major differences between WHO standards Major differences between WHO standards and existing growth charts and existing growth charts

Measurement schedules (21 visits in 24 mo)

Infant feeding modes

Standardization measurement techniques

Availability empirical data in early months!

Mean ZMean Z--scores of healthy breastfed infants scores of healthy breastfed infants relative to the NCHS/WHO referencerelative to the NCHS/WHO reference

Source: An Evaluation of Infant Growth, WHO, 1994

Source: An Evaluation of Infant Growth, WHO, 1994

Weight-for-age Z-scores WHO standard versus NCHS reference

-2.5

-2

-1.5

-1

-0.5

0

0.5

1 3 5 7 9 11 13 15 17 19 21 23 25

Age (mo)

Wei

ght-f

or-a

ge Z

-sco

re

Boys WHO Girls WHOBoys NCHS Girls NCHS

Fuente: Saha KK, Frongillo EA, Alam DS, Arifeen SE, Persson LA, Rasmussen KM. Use of the new World Health Organization child growth standards to describe longitudinal growth of breastfed rural Bangladeshi infants and young children.Food Nutr Bull 2009;30:137-44.

Consistency Consistency

National and international infant feeding guidelines National and international infant feeding guidelines that recommend breastfeeding as the optimal source that recommend breastfeeding as the optimal source of nutrition during infancy of nutrition during infancy

andandThe growth charts recommended for assessing the The growth charts recommended for assessing the

pattern of infant growthpattern of infant growth

NoNo

giftgift

isis

moremore

preciousprecious

BreastfeedingBreastfeeding

• provides perfect nutrition

• provides initial immunization

• prevents diarrhoea

• maximizes a child’s physical

and intellectual potential

• supports food security

• bonds mother and child

• helps birth spacing

• benefits maternal health

• saves money

• is environment-friendly

Severe malnutrition Severe malnutrition

Very low weight/height (Very low weight/height (--3SD)3SD)

19 million preschool age children19 million preschool age children

Mortality risk 9.4 times higher Mortality risk 9.4 times higher

WHO standards impact:WHO standards impact:-- shorter durations of treatmentshorter durations of treatment-- greater rates of recovery greater rates of recovery -- less need for inpatient careless need for inpatient care-- fewer deaths (WHO standards better fewer deaths (WHO standards better predictor of risk of mortality)predictor of risk of mortality)-- the standards have had a profound the standards have had a profound impact on the way programs operateimpact on the way programs operate

Source: Isanaka et al. Pediatrics 2009 and other recent papers

The WHO standards will play a key role in the early identification of childhood overweight and obesity

WHO Child Growth Standards

Source: vanDijk CE, Innis SM. Growth-curve standards and the assessment of early excess weight gain in infancy. Pediatrics (2009)

Nash RD et al. Field testing of the WHO standards: assessment of undernutrition and overnutrition and usefulness of BMI. JPEN 2008;32:145-53.

Comparison of WHO with British 1990 BMIComparison of WHO with British 1990 BMI--forfor--age zage z--scores for boysscores for boys

Source: WHO Multicentre Growth Reference Study Group. WHO Child Growth Standards: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: Methods and development. Geneva: World Health Organization, 2006.

Age (months)

Bod

y M

ass

Inde

x (K

g/m

²)

1012

1416

1820

22

0 2 4 6 8 12 16 20 24 28 32 36 40 44 48 52 56 60

0

-1

-2

-3

1

2

3

WHOBritish

Implications for clinical practice

With the WHO standards the risk of making an incorrect assessment regarding the adequacy of growth in healthy breastfed infants, and mistakenly advise unnecessary supplementation or cessation of breastfeeding is highly reduced

Provide a better tool for the early identification of children in the process of becoming undernourished or overweight

Improve management of severe malnutrition

Implications for clinical practice

WHO weight-based charts represent a lower plane of nutrition: fewer infants will appear thin while more will appear overweight/obese

Shift of focus from "failure to thrive" to "overgrowth"

Important training implications (overweight not previously a problem): how should professionals deal with fat infants?

Will require a change in attitude of both parents and Will require a change in attitude of both parents and professionals to a "bonny baby": growing too fast in infancy is professionals to a "bonny baby": growing too fast in infancy is unhealthyunhealthy

A child's right to grow to his/her full genetic potentialA child's right to grow to his/her full genetic potential

Age (days)

Mea

n of

Len

gth

(cm

)

0 200 400 600

5060

7080

BrazilGhanaIndiaNorwayOmanUSA

NeverNever beforebefore a a growthgrowth standardstandard//referencereference has has beenbeen scrutinized in scrutinized in thethe intense intense andand global global wayway as as thethe WHO standards WHO standards havehave beenbeen ……..

andand theythey havehave passedpassed thethe test test withwith a a goodgood scorescore

WHO WHO ChildChild GrowthGrowth StandardsStandards

1990 91 92 93 94 1995 96 97 98 99 2000 01 02 03 04 2005 06 07 08 09 2010

WHA Resolution(May 1994)

WHO Working Group on Infant Growth

WHO Working Group on Growth Reference

Protocol

WHO Multicentre GrowthReference Study

Field implementation

(July 97)

(Nov 03)

Growth Standards

2nd set

Construction and testing of growth

standards

Growth Standards 1st set: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height, BMI-for-age and motor development indicators

Growth Standards 2nd set: Head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age

WHO Expert Committee recommendation

(Nov 1993)

Growth Standards

1st set

WHO Child Growth Standards TimelineWHO Child Growth Standards Timeline

Velocity Standards

Thank you!