Factors affecting child development in developing countries

Transcription

1 Factors affecting child development in developing countries S Grantham-McGregor Centre for Health and Development, Institute of Child Health, University College London Figure 1.1

2 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) 1. The size of the problem 2. The causes 3. What we can do International Child Development Steering Group: S Grantham-McGregor, P Engle, M Black, J Meeks Gardner, B Lozoff, T Wachs, S Walker Figure 1.2

3 Aims of 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 health & education professionals & policy makers from universities, UN agencies and NGOs consensus for action. Figure 1.3

4 Conception to 5 years 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 Figure 1.4

5 Aims of this paper Estimate the size of the problem of poor development Give an overview of the main causes Figure 1.5

6 Domains of Child Development Sensorymotor Cognitivelanguage Socialemotional Figure 1.6

7 Major problem with estimating numbers of affected children Insufficient data on early cognitive ability for most developing countries Figure 1.7

8 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) Figure 1.8

9 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? Figure 1.9

10 Stunting in children > 28 studies X-sectional associations between stunting & poor cognition or school achievement Figure 1.10

11 Cognitive or schooling deficits associated with moderate stunting <3yrs in 7 longitudinal studies 0.5 z scores 15yrs 7yrs 7yrs 18yrs 9yrs 17-18yrs 18-25yrs Philippines S Africa Indonesia Brazil Peru Jamaica Guatemala Figure 1.11 Lancet paper 1

12 Conclusion Reasonable to use stunting as an indicator of poor child development Figure 1.12

13 Poverty <1 per day >60 X-sectional studies showed associations with wealth and school achievement or cognition Figure 1.13

14 Later cognitive deficits associated with being in the lowest wealth quintile <3yrs in 5 longitudinal 0.5 studies (SD scores) yrs 7yrs 7yrs 18yrs 18-26yrs Philippines Indonesia S Africa Brazil^ Guatemala* ^Grades attained *boys Figure 1.14 Lancet paper 1

15 Conclusion Reasonable to use poverty as an indicator of poor child development Figure 1.15

16 Millions of children < 5y not fulfilling their potential in development (WHO, 2006; UNICEF 2006) m (39% of children <5y) m 126m Stunted + Poverty not stunted 50 0 Stunted Poverty Disadvantaged Figure 1.16

17 Limitations Other risk factors not included Cut off for poverty uncertain Estimate based on poverty rates for total population not children Underestimate Figure 1.17

18 % of disadvantaged children <5yrs by region S-S Africa Mid East & N Africa S Asia E Asia & Pacific La America & Caribbean Central & E Europe Figure 1.18

19 Conclusion Loss of children s potential is an enormous problem affecting >200million It has economic and social costs both to individual and nations (20% loss of yearly adult income) Majority in SS Africa and S Asia Figure 1.19

20 Risk factors affecting child development in developing countries Figure 1.20

21 National / international regional neighbourhood family child Figure 1.21

22 Selection criteria for proximal risks Affect large number of children less than 5 years in developing countries Modifiable by interventions or public policy Information from developing countries Figure 1.22

23 Main risks identified Chronic undernutrition leading to stunting Iodine deficiency Iron deficiency Inadequate cognitive stimulation Figure 1.23

24 IQ scores of stunted and non-stunted Jamaican children from age 9-24 mo to 18 y Non-stunted SD score Stunted Griffiths on Enrollment (9-24 mo) Griffiths (33-48 mo) Stanford- WISC-R Binet ( y) (7-8 8 y) Figure 1.24 WAIS ( y) Walker et al 2005

25 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, oppositional Figure 1.25 Walker et al 2005, 2006

26 All nutrient deficiencies associated poverty : Need randomised trials Figure 1.26

27 Randomised supplementation trials (Guatemala, Bogotá, Mexico, Cali, Indonesia x 2, Jamaica) 6 RCTs and 1 non-randomised: 6 showed concurrent benefits to development (6-13 DQ points Effect size SD) Some benefits to social emotional outcomes Figure 1.27

28 Effect of supplementation on children s developmental quotients (DQs) DQ 110 Jamaica Colombia Control 105 Supplement Age in Months Figure 1.28

29 Long term effects of supplementation Given in pregnancy and early childhood: Sustained benefits to adulthood in cognition and educational achievement (Guatemala, Mexico, Bogota) Given to undernourished children Fewer sustained benefits (Jamaica, Indonesia, Cali, Guatemala ) Figure 1.29

30 Iron deficiency anaemia (IDA) (22-33% of children under 4 y) 21 cross-sectional studies of IDA & non-ida children: 19 found developmental deficits 8 longitudinal studies: all poorer development Figure 1.30

31 Iodine Deficiency Affects 35% of world s population (mild to severe) Preventive programmes primarily through salt iodisation have led to substantial progress Deficiency still compromises development of many children Figure 1.31

32 Inadequate cognitive stimulation or learning opportunities The role of health professionals? Figure 1.32

33 Home visiting or center based Figure 1.33

34 Home made toys Figure 1.34

35 Intervention studies 15 of 16 intervention studies providing cognitive stimulation show benefits to development Centre based or home based: Effect size SD Figure 1.35

36 DQ Effects of visiting frequency in disadvantaged children weekly fortnightly monthly no visits 94 Pre-test Post-test test Figure 1.36 Powell & Grantham-McGregor, 1989

37 Cognitive ability at 7 years by duration of center based intervention; Colombia Cognitive ability Periods of intervention Figure 1.37 McKay et al, 1979

38 DQ Stimulation and supplementation with stunted children: RCT Baseline 6 mo 12 mo 18 mo 24 mo Non-stunted Both Rxs Stimulated Supplemented Control Figure 1.38 Grantham-McGregor et al, 1991

39 Sustained: Benefits at Years From Early Childhood Stimulation in Stunted Children Global IQ Verbal IQ Perform IQ Reasoning Analogies Vocabulary Sent comp Reading comp Arithmetic Digit span B Digit span F Visual spatial P value ** ** * * ** ** *** *** ns ns ns ns *p<.1; **p<.05, ***p<.01 Standard scores Figure 1.39 Walker et al, 2005

40 Sustained: Benefits at years from stimulation in early childhood in stunted children P value Anxiety Depression Self esteem Antisocial Attention deficit Inattention Hyperactivity Oppostional behaviour *p<.1; **p< Figure 1.40 Standard scores ** ** ** ns ** ns ns Walker et al unpublished *

41 Summary of stimulation studies Consistent concurrent benefits to child s DQ Benefits greater in : more intense, longer, include nutrition Sustainable cognitive,education and mental health benefits at 17-18yrs 18yrs Figure 1.41

42 Conclusion: Good evidence for 4 main risks Chronic undernutrition leading to stunting Iodine deficiency Iron deficiency Inadequate cognitive stimulation Figure 1.42

43 Other risk factors Risk factors with consistent epidemiological evidence showing association with development Lack of interventions with evaluation of effectiveness Figure 1.43

44 Other risks identified Small for gestational age Malaria Maternal depression Exposure to violence Exposure to environmental toxins Figure 1.44

45 Developmental risk factors Inadequate stimulation, stunting, iodine and iron deficiencies are critical risks affecting millions of children interventions are urgently needed Other risks where interventions are needed include malaria, exposure to violence and maternal depression Figure 1.55

46 Conclusions Interventions urgently needed begin early integrate health, nutrition & stimulation use all available access points health services often only point of contact Figure 1.56