WHO Child Growth Standards: Evolution, Concepts, Overview Challenges, Issues and Options

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WHO Child Growth Standards Evolution, Concepts,
OverviewChallenges, Issues and Options

• Dr Arvind Mathur
• MD,DHA,DNB
• Cluster Focal Point
• Family Community Health
• WHO-India

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INDICATORS OF NUTRITIONAL STATUS

• Direct Indicators
• -- Nutritional Anthropometry
• -- Clinical Assessment
• -- Bio-chemical Estimations
• -- Biophysical Tests

Indirect Indicators -- Dietary assessment
-- Prevalence of Morbidities -- Vital
Statistics
In addition, Secondary Data -- Socio-economic
-- Demographic -- Environmental
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NUTRITIONAL ANTHROPOMETRY
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Nutritional Anthropometry
Weight - Total Body mass
- Simple, widely used -
Sensitive to small changes in nutrition Height
- Genetically Determined
- Environmentally influenced
- Stunting Reflects long duration undernutrition
MUAC - Reflects
muscle/fat - Easy to measure,
used for quick screening -
Independent of age (1-5 years) Fat Fold
Thickness- Measures body fat
-Correlates well with total body fat

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REQUIREMENTS FOR NUTRITIONAL ANTHROPOMETRY
Standard equipment - Accuracy /
Consistency, Appropriate techniques
- Training Standardization Correct assessment
of age - Wrong age vitiates the results
Reference values - For comparison and
computation of indices Classification
- For grading nutritional status
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Reference Values
Anthropometric measurements obtained on
statistically adequate number of individuals who
are well nourished, representing cross section of
community living in an environment free from
constraints of any sort and have capacity to
reach maximum growth potential at each age
group/Gender. - National E.g. Well-to-do
Hyderabad pre-school children - International
E.g. NCHS, Harvard, MGRS
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Growth charts

• Consist of a series of percentile curves that
  illustrate the distribution of selected body
  measurements in the study population
• Used to track the growth of children from infancy
  thru adolescence
• Indicates the state of the child's health,
  nutrition and well being

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Growth monitoring

• By using growth charts-screening tool for
  diagnosis of nutritional, chronic systemic and
  endocrine diseases

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Need for growth charts

• Individual level
• Community level
• National level
• Scientists

• Monitoring documenting growth
• Comparison with references std
• To detect growth faltering
• Monitoring health status
• Performance of programs
• Comparison over time
• Identification of problem areas
• National/international comparisons
• Research tool

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Community level

• Early identification of childrens growth failure
  for detection of malnutrition and taking
  appropriate interventions
• Early identification-overweight/obesity
• Sensitize health workers
• Educate parents and allay their anxiety by
  showing normal growth in chart

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What needs to be monitored at community level

• Length/age
• Weight/age
• Weight /height or BMI
• Head circumference/age
• Height/age
• Weight/age
• BMI/age
• Above in relation to pubertal development

• First 2 years
• 2 10 years
• gt10 years

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WHO Child Growth Standards

• Why?

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Why Children Should Grow Healthy?

• Child undernutrition or failure of children to
  grow properly in early childhood , results in
  greatly increased child mortality.
• At more than 3000 infants a day, the death toll
  from undernutrition by far exceeds even the
  Tsunami or Bhuj.
• Those children that survive do so with a greatly
  reduced capacity to lead productive and healthy
  lives.

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Rationale for the development of the WHO child
growth standards

• The recommended NCHS/WHO international
  reference is inappropriate for assessing
  nutritional status
• Individual infants
• interferes with sound nutritional management
  of breastfed infants, increasing their risk of
  morbidity and mortality
• Populations
• provides inaccurate estimates of
  undernutrition and overweight

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New WHO growth standards

• The international growth standards established by
  the WHO in April 2006 directly confront the
  notion that ethnicity is a major factor in how
  children grow. The new standards demonstrate that
  children born in different regions of the world
  , when given an optimum start in life , have the
  potential to grow and develop within the same
  range of height and weight for age.
• (ECHUI 2006 Global Framework for Action)

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Why should we adopt new charts?

• The new Child Growth Standards is a crucial
  development in improving infant and young child
  nutrition globally. Unlike the old growth charts,
  the new standards (1) describe how children
  "should grow," (2) establish breastfeeding as the
  biological "norm," and (3) provide international
  standards for all healthy children, as human milk
  supports not only healthy growth, but also
  optimal cognitive development and long-term
  health. 

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Rationale for change to new WHO standards
Corrects the historical fallacy of using
formula fed children from single ethnic group
in one country as global standard for
assessment of nutritional status of preschool
children and consequent problems in
interpretation of data .
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WHO Child Growth Standards

• HOW?

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Milestones in the development of theWHO child
growth standards

• 1991-1993 WHO Working Group on Infant growth
• Comprehensive review shows growth patterns of
  healthy breastfed infants differ from the current
  NCHS/WHO international reference
• A new growth reference is needed to improve
  infant health management
• The reference population should reflect health
  recommendations in view of the frequent use of
  references as standards

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Milestones in the development of the WHO child
growth standards

• 1993 WHO Expert Committee
• Recommends development of a new international
  growth reference
• Based on an international sample of healthy
  infants
• 1994 WHA resolution (WHA 47.5)
• Endorses need for new reference
• Requests it to be based on breastfed infants

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A Growth Curve for the 21st Century
The WHO Multicentre Growth Reference Study
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Approaches for developing growth references

• Descriptive approach
• defines growth on the basis of representative
  samples of healthy groups, i.e., without
  identifiable disease
• Prescriptive approach
• defines growth on the basis of health and feeding
  practices known to promote optimal growth and
  selects the sample accordingly

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WHO Growth Reference StudyPrescriptive Approach

• Optimal Nutrition
• Breastfed infants
• Appropriate complementary feeding
• Optimal Environment
• No microbiological contamination
• No smoking
• Optimal Health Care
• Immunization
• Pediatric routines

Optimal Growth
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MGRS study design
Longitudinal (0-24 months)
year 1
year 2
year 3
Cross-sectional (18-71 mo)
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WHO Child Growth Standards

• Construction
• growth
• standards

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Mean length from birth to 24 months for the six
MGRS sites
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Length at selected centiles for the pooled sample
and the sample following the exclusion of Norway
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Length at selected centiles for the pooled sample
and the sample following the exclusion of India
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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

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WHO Child Growth Standards

• Attained growth
• Weight-for-age
• Length/height-for-age
• Weight-for-length/height
• Body mass index-for-age
• Mid-upper arm circumference-for-age
• Triceps skinfold-for-age
• Subscapular skinfold-for- age
• Head circumference-for-age
• Growth velocity
• Weight
• Length/height
• Head circumference
• Arm circumference

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Prevalence of stunting (below -2 SD
length/height-for-age) by age based on the WHO
standards and the NCHS reference in Bangladesh
Source de Onis M, Onyango AW, Borghi E, Garza C,
Yang H, for the WHO Multicentre Growth Reference
Study Group. Comparison of the WHO Child Growth
Standards and the NCHS growth reference
implications for child health programs. Public
Health Nutrition 20069942-947.
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Prevalence of underweight (below -2 SD
weight-for-age) by age based on the WHO standards
and the NCHS reference in Bangladesh
Source de Onis M, Onyango AW, Borghi E, Garza C,
Yang H, for the WHO Multicentre Growth Reference
Study Group. Comparison of the WHO Child Growth
Standards and the NCHS growth reference
implications for child health programs. Public
Health Nutrition 20069942-947.
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Mean weight-for-age z-scores of healthy breastfed
infants relative to the NCHS, CDC and WHO curves
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Breastfeeding
No gift is more precious

• provides perfect nutrition
• provides initial immunization
• prevents diarrhoea
• maximizes a childs physical
• and intellectual potential
• supports food security
• bonds mother and child
• helps birth spacing
• benefits maternal health
• saves money
• is environment-friendly

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WHO Child Growth Standards
The new standards will play a key role in the
prevention and early recognition of childhood
obesity
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Prevalence of overweight (above 2 SD
weight-for-length/height) by age based on the WHO
standards and the NCHS reference in the Dominican
Republic
Source de Onis M, Onyango AW, Borghi E, Garza C,
Yang H, for the WHO Multicentre Growth Reference
Study Group. Comparison of the WHO Child Growth
Standards and the NCHS growth reference
implications for child health programs. Public
Health Nutrition 20069942-947.
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WHO standards versus NCHS reference

• Important differences that vary by age group,
  sex, growth indicator, specific percentile or
  z-score curve, and the nutritional status of
  index populations.
• Differences are particularly important during
  infancy due to type of feeding and issues related
  to study design (eg, measurement interval)
• Difference in shapes of the weight-based curves
  in early infancy makes interpretation of growth
  performance strikingly different depending on
  whether the WHO standard or the NCHS reference is
  used
• Healthy breastfed infants track along the WHO
  weight-for-age mean z-score while appearing to
  falter in NCHS from 2 months onwards
  implications assessment of lactation performance
  and adequacy of infant feeding

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Comparison of existing growth charts
Data charact Source Study period Population
Age-group
CDC Multiple different studies 1963-1994 US,
mixed feeding, no racial/ethnic diff Birth-20 yrs
WHO Primary data 1997-2003 6 Countries pooled
data. healthy children practices Birth-5yrs
KNA Primary data 1988-1991 Affluent Indian
population, multicentric Birth-18 yrs
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• Use of new WHO growth standards
• Corrects the historical fallacy of using
  formula fed children from single ethnic group
  in one country as global standard and
  consequent problems in interpretation of data .
• Computed under-nutrition rates in the critical
  0-6 month age group with new WHO standard are
  higher as compared to under -nutrition rates
  derived from NCHS/WHO standards this should
  not be viewed with alarm
• Computed under-nutrition rates in 1-5 year age
  with new WHO standard are lower as compared
  to under -nutrition rates derived from NCHS/WHO
  standards this should not lead to complacency

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• Use of new WHO growth standards can make an
  important contribution in clearly bringing into
  focus the importance of nutrition and health
  education in improving infant and young child
  feeding and caring practices and reducing the
  under-nutrition in preschool children

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• Low birth-weight rate in India is 30
• Prevalence of under-weight in first three
  months is 30 suggesting that breast feeding in
  the first three months prevents deterioration in
  nutritional status
• After 3 months underweight rate rises ? due to
  early introduction of milk supplements
• Between 6 and 11 months underweight rate further
  rises to 45 -?due to inadequate complementary
  feeding
• Analysis of data using new WHO norms clearly
  brings out importance of wrong infant feeding
  habits as determinants of underweight in infancy
  and emphasises importance of nutrition
  education to correct them.

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• Progressive increase in the underweight rates in
  12 to 24 months of age ?attributable to
  inadequate intake of family food due to poor
  child feeding practices. Need for nutrition
  education to correct these faulty habits .
• With the availability of new WHO standards for
  weight for age, height for age and BMI for age
  clinicians and research workers can assess which
  of the three indices is the most a appropriate
  index for assessment of functional
  de-compensation in the era when both under and
  overnutrition are public health problems

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Some Questions?

• Individual growth monitoring in children in
  India-Is it possible to achieve?
• Who shall use the growth charts?
• Pediatricians? Family Physicians? Anganwadi
  workers? ASHA? Mothers?
• Capacity Building
• Training of different level of workers/volunteers
• Systematic Changes/strengthening
• How do we introduce the new charts in the
  existing program?
• Are there actions that the CoP members can take?
• More questions!!

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Thank You!