S Grantham-McGregorCentre for Health and Development, Institute of Child Health,

University College London

Child development in developing countries

The Lancet series: The development of children <5 yrs in developing countries

(Grantham-McGregor et al 2007, Walker et al 2007,P Engle et al 2007)

International Child Development Steering Group: S Grantham-McGregor, P Engle, M Black, J Meeks Gardner, B Lozoff, T Wachs, S Walker, Paper 1&2, Y B Cheung, S Cueto, P Glewwe, Richter, B Strupp, J Meeks Gardner, GA Wasserman, E Pollitt, JA Carter

1.The size of the problem2.The causes

Overall Aims of Lancet Series

• To increase awareness of the problem of poor development in early childhood in low resource countries.

• To make the promotion of optimal child development an

international priority.

• Bring together academics from many different disciplines from universities, UN agencies and NGOs to develop a consensus for action.

Aims of paper

• Estimate the size of the problem

• Identify the location of affected children

• Estimate cost and consequences

• Factors causing poor development

Why focus on early childhood?

Brain development most rapid and vulnerable from

conception to 5 years

Insults and interventions can have lasting effects

Interventions are more cost effective than at other ages

Cognitive ability & behaviour on entry school progress

Sensory-motor

Cognitive-language

Social-emotional

Domains of Child Development

Major problem with estimating numbers of affected children

• Insufficient data on early cognitive ability for most developing countries to estimate prevalence

Need to use risk factors as indicators of poor child development to assess prevalence

1. Stunting (<-2SD)

2. Poverty<$1 per day (adjusted for purchasing power by

country, World Bank 2005)

Requirements of indicators

• Standardised measures across countries

• Global data available

• Relevant in most countries

• Consistently related to poor child development and

school achievement in developing countries ?

Stunting in children

> 28 studies X-sectional associations between stunting & poor cognition or schoolachievement

Longitudinal data essential

Jamaica Walker

South African Richter, Norris

Phillipines Cebu study

Uganda data Family Life Study

Brazil Victora, Barros, Damiani, Lima, Gigante, Horta

Peru Berkman, Lescano

Guatemala Martorell

Cognitive or schooling deficits associated with moderate stunting <3yrs in 7 longitudinal studies

-1.5

-1.1

-0.7

-0.3

0.1

0.5

Philippines S Africa Indonesia Brazil Peru Jamaica Guatemala7yrs 7yrs 9yrs 17-18yrs18yrs15yrs 18-25yrs

SD scores

Reasonable to use stunting as an indicator of poor child development

Conclusion

Poverty <1 per day

>60 X-sectional studies showed associations with wealth and school achievement or cognition

Later cognitive deficits associated with being in the lowest wealth quintile <3yrs in 5 longitudinal

studies (SD scores)

-1.5

-1.1

-0.7

-0.3

0.1

0.5

Philippines Indonesia S Africa Brazil^ Guatemala*

^Grades attained *boys

15yrs 7yrs 7yrs 18yrs 18-26yrs

Reasonable to use poverty as an indicator of poor child development

Conclusion

Millions of children < 5y not fulfilling their potential in development (WHO, 2006; UNICEF 2006)

0

50

100

150

200

250

Stunted Poverty Disadvantaged

156m

126m

219m (39% of children <5y)

Stunted +Poverty not stunted

% of disadvantaged children <5yrs by region

0

10

20

30

40

50

60

70

S-S Africa Mid East & NAfrica

S Asia E Asia &Pacific

La America &Caribbean

Central & EEurope

Limitations

• Other risk factors not included

• Cut off for poverty uncertain

• Estimate for numbers of children based on

poverty rates for total population

Underestimate

1. Deficit in grades attained (Brazil)

2. Deficit in learning per grade (Phillipines, Jamaica)

3. Estimate total deficit (1+2)

4. Using estimate of 9% loss in income per grade (53 countries Psacharopoulos 2004, Duflo 2001)

20 % loss of yearly adult income

Loss of yearly adult income

Loss of yearly adult income

Deficit in grades attained

Deficit in learning per grade

% loss of yearly adult income

Mean %

Stunted 0.91 2.0 22.2

19.8%Poor 0.71 ??? 5.9

Stunted & poor

2.15 2.0 30.1

Conclusion

Loss of children’s potential is an enormous problem affecting >200million

It has economic and social costs both to individual and nations

Risk factors affecting child development in low resource countries

Selection criteria

• Modifiable by interventions or public policy

• Affect large number of children less than 5 years in developing countries

• Risks with little information from developing countries excluded

Four main risks

Chronic undernutrition leading to stunting

Iodine deficiency

Iron deficiency anemia (IDA)

• Inadequate cognitive stimulation

Deficits at 17 yrs in Jamaican children stunted before 2 yrs

IQ, vocabulary, cognition

school achievement /drop out

fine motor

depression, anxiety, attention deficit,

self esteem, hyperactive, oppositionalWalker et al 2005, 2006

Inadequate cognitive stimulation or learning

opportunities

A biological insult

Mean Corticosterone Levels Pre & Post Stress in Non-handled, Handled and Maternally-separated Rats

0

5

10

15

20

25

30

35

40

0 60 120

non-handled

maternal separation

handled

0

5

10

15

20

25

30

35

40

0 60 120

non-handled

maternal separation

handled

Plotsky & Meaney 1993

µg/dl

Pre-Pre-stressstress

Time (min)Time (min)

(n= 8 per group)

Intervention studies

• 15 of 16 intervention studies providing cognitive stimulation show benefits to development

• Centre based or home based:

Effect size 0.5-1 SD

Lancet paper2

Effects of Effects of visiting frequencyvisiting frequency in in disadvantaged children disadvantaged children

DQ

Powell & Grantham-McGregor, 1989Powell & Grantham-McGregor, 1989

fortnightlyfortnightly

monthlymonthly

no visitsno visits

94

98

102

106

110

Pre-testPre-test Post-testPost-test

weeklyweekly

75

80

85

90

95

McKay et al, 1979McKay et al, 1979

Cognitive abilityCognitive ability

Cognitive ability at 7 years Cognitive ability at 7 years by durationby duration of center of center based intervention; Colombiabased intervention; Colombia

0

1 2 3 4

Periods of interventionPeriods of intervention

Interventions with stunted Interventions with stunted childrenchildren

85

90

95

100

105

110

Baseline 6 mo 12 mo 18 mo 24 mo

85

90

95

100

105

110

Baseline 6 mo 12 mo 18 mo 24 mo

DQDQnon-stuntednon-stunted

controlcontrol

Grantham-McGregor et al, 1991Grantham-McGregor et al, 1991

both Rxs

supplemented

stimulated

Sustained: Benefits at 17-18 Years From Early Childhood Stimulation in Stunted Children

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Visual spatialDigit span FDigit span B

ArithmeticReading comp

Sent compVocabulary

AnalogiesReasoningPerform IQ

Verbal IQGlobal IQ

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Visual spatialDigit span FDigit span B

ArithmeticReading comp

Sent compVocabulary

AnalogiesReasoningPerform IQ

Verbal IQGlobal IQ

Standard scoresStandard scores

P valueP value

Walker et al, 2005Walker et al, 2005

********************

****** ******nsnsnsnsnsnsnsns

*p<.1; **p*p<.1; **p<<.05, ***p.05, ***p<<.01.01

Sustained: Benefits at 17-18 years from stimulation in early childhood in stunted children

0 0.1 0.2 0.3 0.4 0.5

Oppostional behaviour

Hyperactivity

Inattention

Attention deficit

Antisocial

Self esteem

Depression

Anxiety

0 0.1 0.2 0.3 0.4 0.5

Oppostional behaviour

Hyperactivity

Inattention

Attention deficit

Antisocial

Self esteem

Depression

Anxiety

Standard scoresStandard scores

****

****

****

nsns

****

nsns

nsns

**

P value

Walker et al unpublishedWalker et al unpublished*p<.1; **p*p<.1; **p<<.05.05

• Consistent concurrent benefits to child’s DQ Consistent concurrent benefits to child’s DQ

• Benefits greater in :Benefits greater in :

more intense, longer, include nutrition more intense, longer, include nutrition

• Sustainable cognitive,education and mental Sustainable cognitive,education and mental health benefits at 17-18yrshealth benefits at 17-18yrs

Summary of stimulation studies

Conclusion: Good evidence for 4 main risks

Chronic undernutrition leading to stunting

Iodine deficiency

Iron deficiency

Inadequate cognitive stimulation

Other risk factors

• Risk factors with consistent epidemiological evidence showing association with development

• Lack of interventions with evaluation of effectiveness

Other risks identified

Small for gestational age

Malaria

Maternal depression

Exposure to violence

Exposure to environmental toxins

Multiple risks in early childhood and achievement scores in adolescence

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 2 4 6 8

SD

sco

res

Reasoning Achievement

Gorman and Pollitt, 1996Gorman and Pollitt, 1996

Risk factors

Mean Developmental Quotients on Griffiths TestMean Developmental Quotients on Griffiths Test

90

100

110

120

6 to 17 18 to 29 30 to 41 42 to 53 54 to 59

DQ

Age months

Urban middle class Urban middle class n=78n=78

Urban poor Urban poor n=268n=268

(Walker et al)

Poverty

Poor care and home stimulation

Maternal stress/depressionLow education

Poor cognitive,socio-emotional development

Stunting & wasting, iodine & iron deficiency, diarrhoea, infections

Poor school achievement

Poor sanitation, Food insecurity

Poor hygiene,feeding practices,care-seeking

Childpoor early development

poor school achievementbehavioural problemspoor stimulation,

nutrition & health

Intergenerational transmission of poverty

adultlow educational attainment

low skilled job / no work high fertility

depressed/stressed

nationaleconomy

Countries with highest % of children < 5y who are stunted in Latin America & the Caribbean

(UNICEF 2006)

0

10

20

30

40

50

60

Guatem

ala

Hondura

s

Bolivia

Ecuador

PeruHai

ti

Nicara

gua

LA &

Car

ib

Develo

ping

%

Types of evidence

1. Randomised trials and intervention studies

2. Prospective cohort studies

3. Associational studies (with control for confounders)

Vocabulary scores by SES quartiles in 36 to 72

month old children Equador Paxson and Shady 2005

age in months

Why health services?

• Only service accessing children in first 3 years

• Already has an infrastructure

• Development an integral part of health

• Poor health & nutrition poor development

• Mothers enjoy and can facilitate other activities

• We cannot wait for new services

Why psychosocial stimulation interventions?

• Malnourished children do not catch up with nutrition Malnourished children do not catch up with nutrition alonealone

• Stimulation changes brain function in animalsStimulation changes brain function in animals

• Adoption studies show vast improvement Adoption studies show vast improvement

• In USA disadvantaged children have shown sustained In USA disadvantaged children have shown sustained benefitsbenefits

IQ scores of stunted and non-stunted Jamaican children from age 9-24 mo to 18 y

Non-stuntedNon-stunted

Stunted.Stunted.

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

Griffiths onGriffiths onEnrollmentEnrollment((9-24 mo)9-24 mo)

GriffithsGriffiths(33-48 mo)(33-48 mo)

Stanford-Stanford-BinetBinet(7-8 y)(7-8 y)

WISC-RWISC-R(11-12 y)(11-12 y)

WAISWAIS(17-18 y)(17-18 y)

SD

sco

reS

D s

core

Walker et al 2005

7 longitudinal studies of stunting <3yrs & later function

Country Follow-up age Outcome

Indonesia 7 cognitive test

S Africa 7 cognitive test

Peru 9 IQ

Philippines 15 schooling

Jamaica 17-18 schooling, IQ

Brazil 18 attained grades

Guatemala 18-26 schooling, IQ