Volume 1308, Issue 1 p. 11-32
Original Article
Free Access

Effects of integrated child development and nutrition interventions on child development and nutritional status

Sally M. Grantham-McGregor

Corresponding Author

Sally M. Grantham-McGregor

Institute of Child Health, University College London, London, United Kingdom

Address for correspondence: Sally Grantham-McGregor, Institute of Child Health, University College London, 30 Guilford St., London WC1N IEH, United Kingdom. [email protected]Search for more papers by this author
Lia C. H. Fernald

Lia C. H. Fernald

Department of Community Health and Human Development, School of Public Health, University of California, Berkeley, Berkeley, California

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Rose M. C. Kagawa

Rose M. C. Kagawa

Department of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, California

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Susan Walker

Susan Walker

Tropical Medicine Research Institute, The University of the West Indies, Kingston, Jamaica

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First published: 04 November 2013
Citations: 170


We conducted a systematic review of studies that examined the effect of interventions combining a child development component with a nutrition one; in some cases the nutrition interventions also included health-promotion components. Only papers with both child development and nutrition outcomes and rated as moderate-to-good quality were included. Eleven efficacy and two nonrandomized trials, and eight program evaluations were identified. Only six trials examined interventions separately and combined. The trials showed nutritional interventions usually benefited nutritional status and sometimes benefited child development. Stimulation consistently benefited child development. There was no significant loss of any effect when interventions were combined, but there was little evidence of synergistic interaction between nutrition and stimulation on child development. Only three trials followed up the children after intervention. All at-scale program evaluations were combined interventions. Five benefited child development, but one did not, and two showed deficits. There was generally little benefit of at-scale programs to nutritional status. We found no rigorous evaluations of adding stimulation to health and nutrition services at scale and there is an urgent need for them. There is also a need to establish quality-control mechanisms for existing scaled-up programs and to determine their long-term effects. There is also a need to determine if there are any sustained benefits for the children after programs finish.


Millions of children under 5 years of age in low- and middle-income countries (LMIC) are failing to reach their potential in cognitive, language, and social emotional development,1 which has implications for their educational attainment and adult functioning.2 Poor levels of stimulation in the home, chronic undernutrition (stunting), and iron and iodine deficiencies are key risk factors;3, 4 professionals have called for large-scale programs that integrate health, nutrition, and the promotion of child development.5, 6 There are limited data, however, on the feasibility, benefits, or disadvantages of integrating interventions.

Children acquire skills through interacting with people and objects in their environment,7, 8 and both stunted and iron-deficient children tend to have more passive behavior and limited exploration of their surroundings.9, 10 It is possible that undernourished children could benefit more from stimulation when simultaneously given improved diets. The World Health Organization already recommends incorporating child development activities into the management of malnourished11 and sick children.12

Some practical advantages to integrating interventions are that the health and nutrition sectors are often the only services reaching children under 3 years of age. Furthermore, children with poor health and nutrition are also at risk of poor development. Additional benefits for children could be achieved for lower cost than a stand-alone service, if existing health and nutrition staff could include child development activities in their services.

Conversely, there may be disadvantages to integrating programs. Contacts provided by the routine health and nutrition services are often limited and few are scheduled after 12 months. One study found that more frequent contacts of child stimulation (weekly through monthly), had greater benefits for child development.13 Many health and nutrition services are overstretched, especially in the poorest countries. There is a danger of overloading these services and reducing their effectiveness. At the family level, there may be a limit to the number of messages that a mother can absorb at one time. Another potential issue is the focus on the first 1000 days from conception, which are particularly sensitive to nutrition.14-16 Stimulation continues to have benefits over this age17, 18 and services need to continue.

Although most attempts to integrate child development interventions involve existing nutrition or health services, some early childhood interventions have been attached to conditional cash transfer programs, such as Mexico's Oportunidades conditional cash transfer program.19 However, there are few evaluations of integrated programs at scale.20

Thus, more information is required before policymakers can be confident that integrated programs are the most effective approach to improving children's development and nutritional status. To address this evidence gap, we have conducted a systematic review of the literature to examine the effectiveness of integrated nutrition and stimulation programs. The specific questions are in children under 5 years of age living in LMIC: (1) What are the individual effects of nutrition and psychosocial stimulation on cognitive, language, motor, and socioemotional development, nutritional status and/or health, and how are these effects changed when interventions are combined? and (2) what are the effects of integrated programs on the above?

The focus of this review is on whether the independent effects of the interventions are changed when combined. Although we briefly discuss the independent effects of the separate interventions, studies of single interventions were excluded. Thus, this review does not provide a comprehensive assessment of the effects of individual interventions.


The databases searched and the terms used are given in Box 1 and our inclusion criteria are in Table 1. We searched papers published in English from January 2000 to January 2013 and earlier papers identified in literature searches for the Lancet series1, 3-6 and included sources identified by personal contacts. All studies that were not randomized trials were evaluated by the authors according to the McMaster University Effective Public Health Practice Project (EPHPP) Quality Assessment Tool For Quantitative Studies. Only those of at least moderate quality were included.21 Only papers published in peer-reviewed journals or available online as working papers were included. Twenty studies and program evaluations met these criteria (Fig. 1).

Table 1. Criteria for inclusion
Developing countries (low- or middle-income country)
Children 5 years and under and/or pregnant women
Has at least two components to the interventions (nutrition and stimulation)
Nutrition: micronutrient and/or macronutrient supplementation, nutrition education, breast feeding promotion, or responsive feeding
Stimulation: includes center-based preschool and day care, parent groups, individual parent counseling, or home visiting
Must include a child development and a health or nutrition outcome measure
Child development measures: child cognition, language, motor, socioemotional development, behavior, school retention, school achievement
Nutrition and/or health measures: anthropometry, hemoglobin, morbidity
Must have a control group of similar background and use some method of statistical control for participation
Be rated as being of “moderate” or “good” quality,21 or use econometric methods acceptable for assessing causality (e.g., propensity score matching)
Details are in the caption following the image
Flow chart of evidence search and selection.

We present effect sizes (Cohen's d) for the individual and combined interventions as appropriate. Where possible, we use those presented by the authors. Otherwise, effect sizes were calculated using standard techniques when sufficient information was reported in the paper.22

Box 1. Data bases searched and terms used


   Psychinfo, PubMed, Google Scholar, Global Health, Econ Lit, ISI Web of Science

   Academic Search Complete, the World Bank Web site, UNICEF Evaluation Database

   Brookings Institution Web site

Child development intervention type

   “early childhood development,” “parenting,” “preschool,” “pre-primary,” “early learning,” “stimulation,”

   “educational intervention,” “evaluation,” “assessment”

Nutrition intervention type

   “nutrition,” “breast feeding promotion,” “responsive feeding,” “micro- or macronutrient or nutritionalsupplementation”

Child development outcome measure

   “child development,” “cognition,” “language,” “behavior problems,” “physiology,” “socio-emotionaldevelopment,” “motor development”

Nutrition or health outcome measure

   “health,” “nutrition,” “micronutrient,” “malaria,” “integrated,” “morbidity,” “worms,” and “HIV”


Efficacy studies showing independent and synergistic effects

Six studies allowed an evaluation of the effect of at least one of the interventions (child development and/or nutrition) as well as the combination of the interventions (Tables 2 and 3).23-30 Four studies targeted undernourished children and the others targeted children from poor communities. Sample sizes ranged from 12626 to 600 children30 and children were all under 30 months of age initially with one study beginning in pregnancy.28 Most studies used standard infant development scales.31, 32 In each of the four studies where it was possible to assess the independent effects of the two individual interventions (nutrition and child development) and their combination,23, 26-28 stimulation benefited the children's development; effect sizes ranged from 0.37 SD (Bayley mental development index)27 to 0.88 SD (Griffiths developmental quotient).23 Stimulation benefited weight gain only in the study with the most severely malnourished children.27

Table 2. Randomized controlled trials showing the effect of individual and combined intervention components (≥3 groups)
Study and country Sample size, age, and design Interventions Outcome measures Treatment effects (effect sizes)
Study design: RCT with assignment to one of four+ groups

  • Grantham-McGregor et al.23
  • Walker et al.24
  • Grantham-McGregor et al.25
  • Jamaica

  • 129 stunted children aged 9–24 months.
  • Children randomized to four groups: (1) supplementation, (2) stimulation, (3) supplementation and stimulation, (4) control.
  • 127 children completed trial, 105 assessed at follow-up at age of 22 years.

  • Child development:
  • Weekly hour-long home visits to encourage positive interaction and demonstrate play activities. Homemade toys and simple picture books were provided. Mothers were encouraged to play with child between visits (referred to as stimulation).
  • Nutrition:
  • Supplement-only and combined intervention groups received 1 kg milk-based formula each week.
  • Duration = 24 months.

  • Child development:
  • Locomotor, eye–hand coordination, language, performance, developmental quotient (GMDS)
  • Nutrition/health:
  • Weekly morbidity (by mother report), height, weight, head circumference.

  • Effects correspond to assessments at age of 33–48 months (end of intervention).
  • Child development:
  • Supplementation benefited developmental quotient (d = 0. 59), locomotor (d = 0.67), and performance scores (d = 0.51) (all P < 0.01).
  • Stimulation benefited developmental quotient (d = 0.88) and all subscales (all P < 0.01).
  • Additive benefits for group receiving both interventions (developmental quotient, d = 1.47; P < 0.01).
  • Nutrition/health:
  • Supplement benefited all growth measures in first year of intervention only. No consistent effects of supplementation on incidence or duration of any of 12 symptoms.
  • No effect of stimulation on growth.
  • Effects on morbidity not examined.
  • No additive benefits for group receiving both interventions.

  • Gardner et al.26
  • Jamaica

  • 126 children aged 9–30 months and more than 1.5 Z-scores below the weight-for-age standard.
  • 18 clinics were randomly assigned to receive the stimulation program or not and children were randomly assigned to receive zinc supplements or a placebo. Four study arms: (1) zinc only (n = 21), (2) stimulation only (n = 30), (3) both interventions (n = 25), and (4) control (n = 38).
  • 114 children completed trial and assessed after 6 months.
  • Loss 9.5%.

  • Child development:
  • Home visits that encouraged play and maternal infant interaction (referred to as stimulation).
  • Nutrition:
  • Zinc supplement (10 mg elemental zinc) or placebo.
  • All children received vitamin and iron drops.
  • Duration = 6 months.

  • Child development:
  • Locomotor, eye–hand coordination, hearing and speech, performance, developmental quotient (GMDS).
  • Nutrition/health:
  • Weekly morbidity assessment, length, weight.

  • Child development:
  • Zinc improved eye–hand coordination (d = 0.66,
  • P < 0.05). Stimulation benefited developmental quotient (d = 0.55; P < 0.05), hearing and speech (d = 0.88; P < 0.05), and performance scores (d = 0.74; P < 0.05).
  • Children receiving both interventions had highest scores. Interaction between zinc and stimulation on developmental quotient (d = 0.55; P < 0.05) and eye–hand coordination scores (d = 0.81; P < 0.05).
  • Nutrition/health:
  • Length and weight measures not significantly different among groups.
  • Zinc associated with reduced episodes of diarrhea (P = 0.02) and total days with diarrhea (P = 0.03) compared to controls. No other morbidity effect.
  • Did not analyze any effect of stimulation on nutrition/health outcomes.

  • Nahar et al.27
  • Hossain et al.33
  • Bangladesh

  • 507 recently hospitalized children 6–24 months of age with WAZ < –3 SD.
  • Randomly assigned to five groups: (1) psychosocial stimulation (n = 102), (2) nutritional supplementation (n = 101), (3) both interventions (n = 103), (4) clinic controls (n = 99), and (5) hospital controls (n = 102).
  • Assessments occurred at baseline, 3 months, and 6 months of intervention for BSID-II scores, otherwise assessed at beginning and end.
  • Loss = 36% (less attrition (P < 0.029) among groups receiving supplement than in the other groups).

  • Child development:
  • Clinic visits every 2 weeks for hour-long individual play session.
  • Duration = 6 months.
  • Nutrition:
  • Daily cereal-based supplements (150 kcal for children < 12 months and 300 kcal for > 12 months).
  • Duration = 3 months.

  • Child development:
  • Mental and motor (BSID-II), home environment (HOME Inventory), maternal depression (CES-D).
  • Nutrition/health:
  • WAZ, HAZ, WT/HT, head circumference.

  • Child development:
  • None of the three interventions independently benefited BSID-II scores.
  • Any stimulation (stimulation-only group and combined interventions group) compared to all other groups benefited mental scores (d = 0. 37; P = 0.02). No effect on motor scores.
  • Stimulation-only group compared to hospital and control clinics had better HOME scores (d = 0.38; P = 0.035 and d = 0.39; P = 0.004).
  • Combined interventions group compared to hospital and control clinics had better HOME scores (d = 0.56 and 0.54, respectively, P < 0.001 for both).
  • No effect on CES-D.
  • Nutrition/health:
  • At 3 months, nutritional supplementation group showed better WAZ (P = 0.02), HAZ (P = 0.02), and WT/HT (P = 0.02). All not significant at 6 months.
  • At 6 months, any stimulation (stimulation-only group and combined interventions group) compared to all other groups showed better WAZ (d = 0.26; P = 0.08).

  • Waber et al.28
  • Mora et al.55
  • Colombia

  • 433 families with women in the third trimester of pregnancy. Continued until the child was age 3 years.
  • Prospective study of families randomly assigned to six study arms: (1) supplemented from 6 months to age of 3 years, (2) supplemented from third trimester to age of 6 months, (3) supplemented from third trimester to age of 3 years, (4) no supplement with “maternal education” (parenting) program, (5) supplemented from 6 months to 3 years with “maternal education” (parenting) program, and (6) no treatment.

  • Child development:
  • Home visits to encourage positive interaction and demonstrate play activities. Mothers were encouraged to play with child between visits.
  • Nutrition:
  • Food supplementation provided to pregnant and breastfeeding women and children up to age of 3 years. Supplement included bread, milk, protein, vitamins, and minerals.
  • Duration = 30 months.

  • Child development:
  • Locomotor, personal–social, speech and language, eye–hand coordination, performance, developmental quotient (adapted GMDS), cognitive competence (Corman–Escalona Einstein Scale).
  • Nutrition/health:
  • Height, weight.

  • Child development:
  • Food supplementation from the third trimester through age 3 years produced better scores on the GMDS locomotor (d = 0.76; P < 0.001), personal–social (d = 0.54), speech and language (d = 0.45; P = 0.006), eye–hand coordination (d = 0.52; P = 0.008), and performance (d = 0.43; P = 0.025) subscales and overall developmental quotient (d = 0.59; P = 0.003) compared to no supplementation.
  • “Maternal education,” compared to groups receiving no “maternal education,” produced better speech and language scores only on the GMDS test (d = 0.44; P = 0.049) and higher maximum score on the Einstein Scale (d = 0.79; P < 0.001).
  • The two interventions did not interact on GMDS.
  • Significant interaction between supplementation and “maternal education” on highest maximum score achieved in Einstein prehension scale (d = 0.42; P = 0.047).Object and spatial scales on the Einstein Scale all not significant.
  • Nutrition/health:
  • Children receiving nutritional supplementation from third trimester to 3 years had increased weight (d = 0.17; P < 0.05) and height at 36 months (d = 0.57; P < 0.005) compared to  all nonsupplemented children.

Study design: RCT with assignment to one of three groups

  • Aboud and Akhter29
  • Bangladesh

  • 302 children aged 8–20 months and their mothers identified from nongovernmental organization's list of poor families in 45 rural villages.
  • Cluster-randomized control trial in which villages were assigned to three groups: (1) responsive feeding and stimulation (n = 15), (2) responsive feeding, stimulation, and sprinkles (n = 14), and (3) control (n = 16).
  • About 100 mothers per group.
  • All groups participated in parent group sessions.
  • Conducted pre- and posttest and follow-up assessment for all outcomes except language that had pretest and follow-up only.
  • Loss = 5.6%.

  • Child development:
  • 12 parent group sessions on health, nutrition, and child development (no demonstration or practice) over 7 months only. Groups 1 and 2 received additional stimulation intervention (six more weekly sessions with practice and coaching).
  • Nutrition:
  • Responsive feeding and micronutrient sprinkles (iron, zinc, folate, vitamin A and C).

  • Child development:
  • Home environment (HOME Inventory), mother–child responsive talk (mother–child picture-talk task), language (mental development scale of BSID-II).
  • Nutrition/health:
  • Height, weight, mouthfuls eaten, hand washing, percentage of self-feeding.

  • Child development:
  • Both intervention groups had better HOME scores (d = 0.38; P = 0.007), maternal responsive talking (d = 0.4; P = 0.003), and child language scores (d = 0.35; P = 0.02) compared to the control group.
  • No significant differences between intervention groups.
  • Nutrition/health:
  • Both intervention groups received better scores on mouthfuls eaten (d = 0.35; P = 0.01) and hand washing compared to the control group.
  • Children in stimulation-and-sprinkles group showed more weight gain (d = 0.38; P = 0.02) compared to children in stimulation-only group, not different from control group.
  • No other significant differences between intervention groups.
  • Children in stimulation-only group compared to control group showed no significant difference in weight or height.

  • Vazir et al.30
  • India

  • 60 villages with total 600 pregnant women in last trimester.
  • Intervention from 3 to 15 months of child's age.
  • Cluster-randomized trial with home-visiting intervention in which sets of three villages matched for size, maternal literacy, and birth rate were stratified and randomized to three groups: (1) nutritional education, (2) nutritional education with responsive feeding and child development intervention, and (3) control.
  • Loss = 15%.

  • Child development:
  • Weekly or monthly home visits with demonstration of play and five toys given.
  • Nutrition:
  • Group 1: Nutritional education included home visits with information on breastfeeding and complementary feeding following PAHO/WHO guidelines.
  • Group 2: Same as 1 and responsive feeding including demonstrations following PAHO/WHO guidelines. Thirty scheduled visits from 3 to 15 months of age for groups 1 and 2.
  • All groups received routine-integrated child development services including supplemental food, counseling on breastfeeding and complementary feeding, nonformal preschool, and other services.

  • Child development:
  • Mental and motor (BSID-II), maternal depression (CES-D), maternal knowledge on stimulation.
  • Nutrition/health:
  • Hemoglobin, height, weight, morbidity, dietary intake, maternal knowledge on complimentary feeding, and responsive feeding.

  • Child development:
  • Nutrition education only, compared to controls, showed no significant difference in mental scores.
  • Education and play associated with improved mental scores (d = 0.36; P = 0.03) compared to control group.
  • Motor development differences all not significant.
  • Both interventions (education-only and education and play) associated with improved maternal knowledge compared to control group.
  • Nutrition/health:
  • Education-only compared to control showed significant association with growth in HAZ (d = 0.23) and reduced episodes of morbidity (d = –0.73; P < 0.001).
  • Education and play compared to control showed significant association with reduced episodes of morbidity (d = –0.64; P = 0.001), but growth in HAZ not significant.
  • Both interventions (education-only and education and play) compared to control associated with better child diet diversity and change in hemoglobin (d = 0.21; P < 0.05).
  • WAZ, growth in WAZ, WT/HT, and HAZ all not significant at 15 months.
  • Education-only compared to education and play showed no significant difference in growth in HAZ or morbidity.
  • No P-values for growth.


  • Significance determined at P < 0.05 level. GMDS, Griffith's Mental Development Scales; d, Cohen's d effect size; BSID-II, Bayley Scales of Infant Development-II; HOME, Home Observation for Measurement of the Environment Inventory; CES-D, Center for Epidemiological Studies-Depression Scale; WAZ, weight for age Z-score; HAZ, height for age Z-score; WT/HT, weight for height; SD, standard deviation; kcal, kilocalories.
Table 3. Independent and combined intervention effects on child nutritional status and cognitive, language, and motor developmental outcomes at the end of treatment period
Nutrition intervention independent effects Child development intervention independent effects Combined effects
Outcome measures Nutrition/health Developmental quotient Nutrition/health Developmental quotient
Four-group design
Grantham-McGregor et al.23

  • Height, weight, and head circumference significant
  • Morbidity not significant

Locomotor, performance, and developmental quotient significant Not significant Performance, eye–hand, language, locomotor, and developmental quotient significant

  • No change in independent effects
  • No interaction

Nahar et al.27 Growth not significant Not significant WAZ significant Mental score significant

  • No change in independent effects
  • No interaction

Waber et al.28 Weight, height significant Locomotor, language, performance, personal, social, and developmental quotient significant Not significant Language significant

  • No change in independent effects
  • No interaction

Gardner et al. 26

  • Reduction in diarrhea significant
  • Growth not significant

Eye–hand coordination significant Not significant Developmental quotient, language, and performance significant Interaction on developmental quotient and eye–hand significant
Three-group design

  • Vazir et al.30
  • Adding stimulation to nutrition

Change in HAZ and reduced morbidity significant Not significant NA NA

  • Mental score significant
  • Change in HAZ no longer significant
  • No change in independent effects on morbidity

  • Aboud and Akhter29
  • Adding nutrition to stimulation

NA NA Not significant Language significant

  • Weight gain significant
  • No change in independent effects on language


  • Significance determined at P < 0.05 level.
  • NA, Not applicable; WAZ, weight for age Z-score; HAZ, height for age Z-score.

The nutritional intervention was macronutrient supplementation in three trials23, 27, 28 and zinc supplementation in one.26 The macronutrients independently benefited the children's developmental quotients in two studies—(d = 0.81 SD)23 and (d = 0.59 SD)28—but did not benefit child development in the third.27 Zinc supplementation benefited eye–hand coordination.26 When zinc and stimulation were combined, there was a significant interaction between them on developmental quotient (DQ) and eye–hand coordination, with greater benefits for children who received both zinc and stimulation. This is the only example we found of a synergistic interaction. In the other three studies, the independent effects of the interventions did not change when combined.

Nutritional supplementation improved growth in all three studies using macronutrients,23, 27, 28 but in Bangladesh27 the supplement was stopped after 3 months and the growth benefit was lost during the subsequent 3 months. Zinc supplementation26 did not benefit growth, but reduced the frequency and duration of diarrhea, whereas macronutrient supplementation did not reduce morbidity in the Jamaican study.25 There were no differences in unscheduled clinic visits or hospitalization in severely malnourished Bangladeshi children.27, 33 There were no significant interactions between the treatments on growth or morbidity.

Two studies with three groups allow the assessment of independent effects of either the nutrition or stimulation intervention and the combined interventions.29, 30 In both studies, the child development intervention benefited mental development or language. When multiple-micronutrient supplementation was added to stimulation, an additional benefit to weight gain occurred29 and the effect of stimulation remained the same (language 0.35 SD). In the other study,30 nutrition education benefited height for age. When psychosocial stimulation was added, there was a benefit to mental development (Bayley II 0.36 SD), but the gain in height was no longer significant. This is the only reduction in the independent effects of the interventions found when combining treatments, but the difference in gain in height for age with stimulation compared with nutrition education only was not significant.

Studies of the effect of adding one component to another intervention or of combined interventions

Six studies that examined the effects of adding one component to another intervention and one combined intervention17, 34-39 are detailed in Table 4; all but two34, 40 were randomized. Most of the studies examined children who were similar in age to those in Tables 2 and 3, but in two studies, the children were initially over 36 months.17, 35 Most studies used well-recognized cognitive tests. Four studies added a child development component to an existing health and nutrition or nutrition-alone interventions36, 37, 40 and all had significant benefits to the child development outcomes, with effect sizes varying from 0.21 SD 34 to 0.91 SD.37 In a fifth study, there were iron-deficient anemic (IDA) and nonanemic iron-sufficient groups38 and all groups received iron supplementation. Only the IDA group benefited from additional stimulation. There were no differences in nutrition or health outcomes with addition of a child development component except in one study in which the children gained more weight.40

Table 4. Studies showing effect of combined interventions on child development and nutrition or health outcome (two groups)
Study and country Sample size, age, and design Interventions Outcome measures Treatment effects (effect sizes)
Child development intervention added to existing nutrition intervention

  • Hamadani et al.36
  • Bangladesh

  • 206 undernourished children aged 6–24 months with WAZ < –2 SD registered at 20 community nutrition centers.
  • Cluster-randomized controlled trial with 20 community nutrition centers randomly assigned two groups: (1) stimulation (n = 104 children) and (2) control (n = 102 children).
  • Assessment on enrollment and after 12 months.
  • Loss = 4.5%.

  • Child development:
  • Weekly group meetings at nutrition centers for 10 months, then fortnightly for 2 months. Topics included child development and play. Home visits twice weekly for 8 months, then weekly for 4 months. Lent toys, promoted positive mother–child interaction, and demonstrated play activities.
  • Mean number of group meetings = 23.
  • Mean number of visits = 68.
  • Nutrition:
  • Nutrition supplementation through community nutrition centers for undernourished children.
  • Supplement included 0.63–1.26 KJ/day for mean of 70 (stimulated) and 76 (control) days.

  • Child development:
  • Mental, motor (BSID-II), responsiveness to examiner, infant activity, emotional tone, cooperation with test procedures, vocalization (Wolke's behavior ratings); mother's childcare knowledge (questionnaire).
  • Nutrition/health:
  • HAZ, WHZ, WAZ.

  • Child development:
  • The stimulated group showed improved mental scores (d = 0.33; P = 0.05) and ratings on vocalization (d = 0.30; P = 0.04), cooperation (d = 0.41; P = 0.005), response to examiner (d = 0.48; P = 0.001), emotional tone (d = 0.32; P = 0.03), and mother's knowledge (d = 1.04) compared to controls.
  • Nutrition/health:
  • Neither group improved in HAZ, WHZ, or WAZ.

  • Lozoff et al.38
  • Chile

  • Two cohorts of infants aged 6 (n = 128) and 12 months (n = 149) on enrollment.
  • Infants stratified by iron-deficient anemia status and randomly assigned to two groups: (1) surveillance visits with oral iron-only (n = 62 and 79 for 6- and 12-month cohorts, respectively) and (2) intervention visits and oral iron (n = 66 and 70 for 6- and 12-month cohorts, respectively).
  • Outcomes measured on enrollment and 6 and 12 months later.

  • Child development:
  • Weekly 1 hour home visits to support the child–mother relationship. The visits included modeling positive feedback, play activities, and information about child development.
  • Nutrition:
  • Weekly oral iron and monitoring of iron intake, feeding, and health.

  • Child development:
  • Mental and motor scales (BSID), object orientation, motor quality, negative affect, positive social responsiveness (Behavior Rating Scale).
  • Health/nutrition:
  • Hemoglobin.

  • Child development:
  • Stimulation significantly associated with improved mental scores in children with iron-deficiency anemia.
  • Motor scores all not significant.
  • Stimulation significantly associated with improved positive social responsiveness scores among children with iron-deficiency anemia, but these children did not catch up with the noniron-deficient anemic children.
  • No effect of stimulation in nonanemic children.
  • Nutrition/health:
  • Both cohorts of children with iron-deficiency anemia showed improved hemoglobin. The 6-month cohort mean hemoglobin after 12 months of receiving iron was 122.1 g/L and the 12-month cohort hemoglobin after 12 months of receiving iron was 124.4 g/L.
  • (It was not possible to calculate Cohen's d.)

  • McKay et al.17
  • Perez-Escamilla and Pollitt39
  • Colombia

  • 333 children close to 3 years of age with the lowest HAZ and WAZ, signs of malnutrition, and from homes in the lowest socioeconomic position.
  • 301 began study.
  • Recruitment area divided into sectors, which were stratified by level of nutritional status and income. Sectors randomized to five groups: (1a) one treatment period, (1b) one treatment period with prior nutritional and health care, (2) two treatment periods, (3) three treatment periods, and (4) four treatment periods.
  • About 60 children per group.
  • Five data collection points over 3.5 years, once at enrollment and four times over intervention periods.
  • Loss = 18% in treatment groups.

  • Child development:
  • Center-based program that provided education supporting language development, social abilities, and psychomotor skills. There were about 180 treatment days in each of the four periods. The program was offered 5 days a week, 6 hours a day.
  • The group receiving four treatment periods began at age 42 months, and the group receiving only one treatment period began at 75 months. All groups ended treatment at 84 months.
  • Nutrition/health:
  • Children at centers fed 75% of daily-recommended allowance of protein and calories. They were given supplements with vitamin A, thiamine, riboflavin, niacin, and iron (100% of daily recommended).
  • Also given health care.

  • Child development:
  • Language usage, memory, motor control, manual dexterity, information and vocabulary, quantitative reasoning, spatial reasoning, logic, and verbal and nonverbal production. Test scores formed a scaled score indicating general cognitive ability.
  • Nutrition/health:
  • HAZ and WAZ.

  • Child development:
  • At 87 months, groups receiving four (d = 0.90), three (d = 0.65), and two (d = 0.43) treatment periods showed higher scores on general cognitive ability compared to the groups that received only one treatment period. The magnitude of gains decreased as age of entry increased.
  • Groups generally only significantly different if number of treatment periods received differed by two or more.
  • (P-values not given).
  • Nutrition/health:
  • The group with four treatment periods gained 0.6 SD in height for age and 0.7 SD in weight for age compared with the group that received one treatment session (see Table 6 for details).

  • Nahar et al.40
  • Bangladesh

  • Children 6–24 months of age with severe acute malnutrition (<50% WAZ or <70% WLZ or edema) admitted to the nutritional rehabilitation unit in Dhaka hospital. All lived in area accessible to Dhaka.
  • Time-lagged controlled study, not randomized, consisting of two groups: (1) controls were all eligible children admitted in the first 10 months of the study; these children received usual treatment (n = 56) and (2) treatment included children enrolled for the following 11 months into same hospital ward; these children received usual treatment and stimulation intervention (n = 54). Treatment and controls matched for age. Both groups had similar socioeconomic background. All children stayed in nutrition rehabilitation unit with mothers for 2 weeks for treatment of severe acute malnutrition.
  • Assessed on enrollment, on leaving hospital, and 6 months later.
  • Loss = 39% (more in intervened group).

  • Child development:
  • Daily individual and group play sessions in hospital, lasting 30 min. Sessions included demonstrations of play using activities and homemade toys. After leaving hospital, total of 18 play sessions over 6 months at outpatient clinics or home visits (referred to as stimulation).
  • Nutrition/health:
  • All received basic health and nutritional care and education routinely given in hospital. On discharge they visited nutrition rehabilitation unit for follow-up and received growth monitoring and micronutrient supplementation twice in first month and then monthly for 6 months.

  • Child development:
  • Mental and motor scales (BSID-II), five behavior ratings during the test.
  • Nutrition/health:
  • WAZ, WLZ, LAZ.

  • Child development:
  • On leaving hospital no significant difference between groups in BSID-II scores.
  • 6-month follow-up: Stimulation improved mental (d = 0.97; P < 0.001), and motor scores (d = 0.56; P = 0.02).
  • No significant effect on behavior ratings.
  • Nutrition/health:
  • On leaving hospital no significant difference between groups in measures of growth.
  • 6-month follow-up: Children in stimulation showed improvement in WAZ (d = 0.52; P = 0.03).
  • No significant effect on WLZ or LAZ.

  • Powell et al.37
  • Jamaica

  • 129 undernourished children aged 9–30 months attending nutrition clinics.
  • 18 clinics randomly assigned to stimulation intervention (n = 65 children) or control (n = 64 children).

  • Child development:
  • Community health workers visited the homes for 30 min on a weekly basis for one year, to demonstrate play activities, introduce the children and mothers to new toys, and discuss parenting issues (referred to as stimulation).
  • Nutrition/health:
  • All families received education on health and nutrition.

  • Child development:
  • Developmental quotient, locomotor skills, hearing and speech, eye–hand coordination, performance (GMDS), mothers’ childrearing knowledge and practices (questionnaires).
  • Nutrition/health:
  • Height, weight, body mass index.

  • Child development:
  • Stimulation associated with significant benefits for developmental quotient (d = 0.83; P < 0.001), hearing and speech (d = 0.78; P < 0.001), eye–hand coordination (d = 0.70; P < 0.001), performance (d = 0.71; P < 0.001), and for mothers’ childrearing knowledge (d = 1.44; P < 0.001) and practices (d = 0.51; P < 0.01).
  • No significant difference in locomotor skills.
  • Nutrition/health:
  • No difference in height, weight, or body mass index.

  • Watanabe et al.34
  • Vietnam

  • 313 children aged 0–5 years in five communes. Children were aged 6.5–8.5 years at follow-up.
  • Nonrandomized controlled study. The nutrition intervention targeted children aged 0–36 months in five communes. The stimulation intervention targeted children aged 4–5 years in two of the five communes (selected because their preschool services were of lower quality). Two communes were selected for evaluation; one had received both interventions and one nutrition only.

  • Child development:
  • Preschool quality improvement, monthly parent training sessions on childcare and development, play corners in the homes of the children, and a local library (referred to as stimulation).
  • Nutrition/health:
  • Growth monitoring and a 12-day nutrition education program implemented on nine occasions during which nutrition and health-seeking behaviors were taught and children were fed local, nutritious food.
  • Approximately half the families attended on at least one occasion.

  • Child development:
  • Cognitive development (RPM).
  • Nutrition/health:
  • HAZ, WAZ.

  • Child development:
  • Children receiving the stimulation and nutrition interventions had higher Raven's Matrices scores compared to children that only received the nutrition intervention (d = 0.21), but the difference was not statistically significant.
  • Among stunted children, children in the combined stimulation and nutrition interventions scored higher on the RPM test compared to stunted children in the nutrition intervention only group (d = 0.67; P = 0.01).
  • Nutrition/health:
  • No difference in HAZ or WAZ.

  • Ogunlade et al.35
  • South Africa

  • 151 preschool-aged children aged 36–79 months.
  • 76 children were randomized to treatment and 75 to control.

  • Child development:
  • All children attended preschool.
  • Nutrition/health:
  • All children received breakfast maize porridge in their preschool program. The treatment group received a micronutrient powder (about 8 g) and control children received a placebo powder for 52 school days.

  • Child development:
  • Learning scale, sequential scale, simultaneous scale, mental processing index, nonverbal index (KABC-II).
  • Nutrition/health:
  • Hemoglobin concentration, height, weight, mid-upper arm circumference, triceps skinfold thickness.

  • Child development:
  • Children in the treatment group scored higher on the mental processing index (d = 0.36; P = 0.072), higher on the nonverbal index (d = 0.55; P = 0.002), and higher on the subtest of simultaneous processing (conceptual thinking) (d = 0.48; P = 0.008) compared to children in the control group.
  • No other significant effects.
  • Nutrition/health:
  • Improvement in hemoglobin in treatment group not significant.
  • All anthropometric outcomes not significant.

  • BSID-II, Bayley Scales of Infant and Toddler Development—Second Edition; BSID, Bayley Scales of Infant and Toddler Development; GMDS, Griffith's Mental Development Scales; RPM, Raven's Progressive Matrices Test; KABC-II, Kaufman Assessment Battery for Children—Second Edition; d, Cohen's d effect size; SD, standard deviation; HAZ, height for age Z-score; WHZ, weight for height Z-score; WLZ, weight for length Z-score; LAZ, length for age Z-score; WAZ, weight for age Z-score; g, grams; g/L, grams per liter.

In a study adding micronutrients to meals at a preschool, there was a benefit for child development (three subscales of the Kaufman Assessment Battery; d = 0.55–0.36 SD) but not nutritional status.35 The final study examined a high-quality center-based preschool with meals providing 75% of recommended daily requirements of calories and protein.17, 39 Children received one to four 9-month treatment periods of approximately 180 days each with interperiod breaks. The children's cognitive ability showed a dose response with the effect size varying from 0.9 SD after four treatments to 0.42 SD after two treatments, compared to the group that only received one treatment period. Catch up in height and weight for age showed a similar relation to number of treatment periods.

Program evaluation

There were eight program evaluations reported in seven papers (Table 5). They tended to have larger sample sizes, ranging from of 30041 to over 10,000.42 All programs had components of nutrition or health and child development combined, so it is not possible to tease out their independent effects. Six of the programs included a center-based component of either full-day care or preschool, some of which were in the caregiver's home. One was parent groups only41 and one was a general upgrading of health, nutrition, and social services, which included clinics, home-visiting programs, day care, and preschools;43 one study also compared center-based care with home visiting.44 The nutritional intervention was often meals given to the children while at the center, although three involved parental education on nutrition.41, 44, 45 None of the studies were fully randomized but used various econometric techniques to control for participation.

Table 5. Evaluations of integrated programs
Study and country Sample size, age, and design Interventions Outcome measures Treatment effects (effect sizes)

  • Aboud41
  • Bangladesh

  • 329 children aged 2–3 years during the intervention program.
  • Nonrandomized controlled trial including two groups: (1) 22 intervention villages (n = 170 children) and (2) 22 control villages where intervention was not available (n = 159 children). In the treatment group, only assessed children aged 30–48 months whose mothers had attended program in previous year. Controls selected from house-to-house survey and enrolled if children met age criteria.
  • No significant difference found between groups in baseline demographics.
  • Assessed with posttest only.

  • Child development:
  • Education on stimulation, including toy making, talking, and child development.
  • Mean number of sessions attended = 16.
  • Nutrition/health:
  • Education on hygiene and nutrition. Groups of 20 met weekly for 90 min over 1 year. Groups were led by women with some secondary education, 17 days of training and a manual. The group leaders were supervised 4 days a month.

  • Child development:
  • Maternal child rearing knowledge (17 open questions), home environment (HOME Inventory), mother–child interaction (observation while mothers and children looked at pictures), receptive vocabulary (subscale of WPPSI-III).
  • Nutrition/health:
  • Mother's report of health practices, such as immunization and latrine use. Child's WHZ, WAZ.

  • Child development:
  • Significant treatment effect on maternal knowledge (d = 0.31; P < 0.001) and home environment (d = 0.34; P = 0.002).
  • Benefits from stimulation greater if mothers had at least 1 year of education.
  • Quality of mother–child verbal interaction and child receptive vocabulary not significantly different.
  • Nutrition/health:
  • Intervention significantly associated with positive health practices (d = 0.34; P = 0.002), especially use of latrine.
  • Negative treatment effect for WHZ(d = –0.24; P = 0.02).
  • WAZ not significantly different.

  • Armecin et al.43
  • Philippines

  • Longitudinal data collected in three surveys over 3 years in three cohorts (early intervention, later intervention, usual services).
  • 7922 children aged ≤4 years in first survey, 6774 (86% of original sample) followed in second and third surveys in same areas.
  • High-risk towns (34–49% children stunted) opted into the program.
  • For the evaluation, randomly selected barangays in each region, resulting in three treatment groups: (1) intervened barangays (n = 4140 children), (2) nonintervened barangay but in program region (n = 194 children), and (3) nonprogram region (n = 2359 children).
  • Selected 24 households with children 0–6 years of age or pregnant women in each barangay. Tested children 0–4 years of age.
  • Used difference in differences and propensity score matching (nearest neighbor) analysis.
  • Loss = 9%.

  • Child development:
  • Upgrading a combination of services, including day care centers, preschools, health stations, home-based day care, and home visits by health workers. New child development workers educated parents on early child development.
  • Mean duration = 14 months.
  • Nutrition/health:
  • Workers monitored child health, linked child to services, and provided nutritional supplements.

  • Child development:
  • Gross and fine motor skills, receptive and expressive language, cognitive development, social–emotional development, and self-help (instrument developed and standardized for this study in the Philippines—contains 9 to 22 items per scale).
  • Nutrition/health:
  • HAZ, WHZ, percentage wasted, percentage stunted, worms, diarrhea, hemoglobin, percentage anemic.

  • Child development:
  • Significant treatment effect on cognitive, language, social—emotional, and gross and fine motor development compared to controls. Varies by duration and age at the end. Results presented by separate coefficients by age and duration.
  • Average of positive effect sizes (intent to treat):
  • Expressive language = 1.09 SD
  • Cognition = 0.55 SD
  • Gross motor = 0.79 SD
  • Fine motor = 0.65 SD
  • Self-help = 0.33 SD
  • Socio–emotional = 0.55 SD (with one negative coefficient)
  • Receptive language = 1.13 SD (with two negative coefficients)
  • Nutrition/health:
  • WHZ = 0.234 SD (with one negative coefficient).
  • Height effect inconsistent.
  • Hemoglobin-significant negative effect.
  • Diarrhea and worms not significant.
  • (We use SDs reported by authors rather than Cohen's d.)

  • Behrman et al.46
  • Bolivia

  • Children aged 6–72 months, living in poor neighborhoods.
  • Used a generalized matching estimator to control for selectivity into the program.
  • Two surveys with three study arms: (1) children in the program for over one month (n = 1198, 2420, 364 in first, second, and both surveys, respectively), (2) children who live in similar areas without the program (n = 558, 987, and 415 in first, second, and both surveys, respectively), and (3) children in the catchment area but not in the program (n = 333, 963, and 247 in first, second, and both surveys, respectively). Also compared children in Proyecto Integral de Desarollo Infantile for <2 months with those in the program ≥2 months.

  • Child development:
  • Full-time child care centers based in private homes that provide a stimulating environment with educational activities. Up to 15 children per center with 1 staff member per 5 children.
  • Nutrition/health:
  • Given 70% of the children's recommended dietary allowance.

  • Child development:
  • Gross and fine motor skills, language, and psychosocial skills (tests not named or described).
  • Nutrition/health:
  • Height for age percentile, weight for age percentile.

  • Child development:
  • Presents results by age and duration of intervention. Full details not given here.
  • Children in the program scored slightly higher on gross and fine motor, language, and psychosocial tests compared to children in the control groups. Effects varied by age and duration. Only children in program for more than 7 months showed significant benefits.
  • Many effects comparing children in the program for more than a month with children in either control group (groups in which children did not participate in the program) show a suggestive trend at 10% level. For example, at a duration of 25 months or more, 7 of 13 coefficients for gross and fine motor, language, and psychosocial were marginally significant at P < 0.1.
  • Nutrition/health:
  • No benefit on height for age or weight for age percentiles.

  • Bernal & Fernandez42
  • Colombia

  • 10,173 low-income children aged 3–6 years.
  • Nonrandom assignment to treatment. Propensity score matching used to compare children with different durations of program exposure. Controls for observed confounders. Four groups defined by length of exposure: (1) 1 month or less (control group), (2) 2–4 months, (3) 5–15 months, (4) >16 months.

  • Child development:
  • Home-based childcare “Hogares Comunitarios de Bienestar” providing psychosocial stimulation.
  • Up to 15 children per center, full time or part time.
  • Nutrition/health:
  • Nutritional supplements (50–70% of daily-recommended allowance).

  • Child development:
  • Physical, cognitive, social, and emotional development (EDI), receptive language (Spanish-adapted PPVT), general knowledge, cognitive and verbal ability, mathematical reasoning (Woodcock–Muñoz Bateria-III), behavior, interaction, withdrawal, disruption (PIPPS).
  • Nutrition/health:
  • HAZ and WAZ.

  • Child development:
  • Participation in the program for >16 months was associated with a trend for positive effects on PPVT scores (0.15–0.30 SD; P < 0.10),a mathematical reasoning (0.24 SD; P < 0.10), and general knowledge (0.15–0.24 SD; P < 0.10)a subscales of the Woodcock–Munoz and a significant benefit to the verbal ability (0.14–0.20 SD; P < 0.05)a of the Woodcock–Munoz compared to control children.
  • Younger children in the program for >16 months showed a trend for less withdrawal and isolation on the PIPPS subscales (0.33 SD; P < 0.1) compared to control children.
  • However, longer participation in the program associated with increase in disruptive play behaviors (0.17 SD; P < 0.05).
  • For children older than 49 months, participation in the program was associated with a trend for positive effects on the cognitive EDI subscales (0.15–0.50 SD; P < 0.10).b
  • Social and emotional EDI subscales all not significant.
  • Nutrition/health:
  • Children older than 49 months and exposed to the program for >16 months showed a trend for a higher HAZ (0.10 SD; P < 0.10) compared to control children.
  • No other significant nutritional effects.
  • (Used SDs reported by authors rather than Cohen's d.)

  • Martinez et al.45
  • Mozambique

  • 2000 households in poor rural settings, with children aged 36–59 months.
  • Communities randomly assigned to intervention or control. Surveys conducted at beginning and 2 years later. First graders at primary school also tested.
  • 5% loss.

  • Child development:
  • Community-built preschools, program assisted with classrooms. Preschool-provided learning and play activities. Focus on preliteracy and numeracy skills. Teachers had 5 days initial training then monthly mentoring. Run by the community.
  • Health/nutrition:
  • Monthly parent meetings that focused on various topics, including health, nutrition, and literacy. Program assisted with latrines and hand washing stations.

  • Child development:
  • Problem solving, language, gross and fine motor development (ASQ), receptive language (PPVT), behavior problems (SDQ), physical health and well-being, social competence, emotional maturity, cognitive development and language, communication skills (EDI).
  • All tests modified for Mozambique.
  • Health/nutrition:
  • Height, weight, morbidity.

  • Child development:
  • In intervention communities, 5.8% more children aged 5–9 years enrolled in primary school (d = 0.13; P < 0.01) (increased to 24.2% when used instrumental variables for participation), and 46% increase in time spent on school-related activities (d = 0.16; P = 0.01) compared to control communities.
  • Intervention children scored better on total ASQ (d = 0.09; P < 0.05), and problem solving subscale (d = 0.09; P < 0.05), with a trend for better scores in communication and fine motor subscales (P < 0.1). Gross motor not significant.
  • Benefits to EDI cognitive subscale (d = 0.10; P = 0.05), other EDI subscales not significant.
  • PPVT not significant.
  • Caregivers in intervention group more likely to work (d = 0.80) and older siblings more likely to attend school.
  • Limited number of significant improvements in caregiver attitude (disagree with physical punishment, satisfied with child's preparation for school, no change in stimulation in the home).
  • SDQ results not given.
  • Nutrition/health:
  • Stunting, wasting, and morbidity not significant.

  • Rosero and Oosterbeek44
  • Ecuador

  • Children aged 0–6 years from a rural community.
  • Regression discontinuity and difference-in-differences. The regression discontinuity uses a cutoff score that determines whether a program is funded. Children in programs above the cutoff were classified as treatment and children signed up for programs, below the cutoff became controls because these programs were not funded.
  • 988 children in the home-visit program and 830 controls.
  • 478 children in child care centers and 411 controls.

  • Child development:
  • Fondo de Desarrollo Infantil childcare centers provided care and education 8 h a day, 5 days a week, 52 weeks a year.
  • Home visits involved child stimulation and parent education, including how to engage with their children.
  • Nutrition/health:
  • Childcare centers provided two meals per day and home visits taught how to prepare nutritional meals.

  • Child development:
  • Receptive language (Spanish-adapted PPVT), long-term memory (Woodcock–Johnson–Muñoz), fine motor skills (pegboard), language skills, gross and fine motor skills, social behavior (Nelson–Ortiz), maternal depression (CES-D), home environment (HOME Inventory).
  • Nutrition/health:
  • Height for age, weight for age, anemia.

  • All findings reported for children older than 36 months.
  • Child development:
  • Children in home-visit program had higher memory scores (0.55 SD; P < 0.01), language scores (0.29 SD; P < 0.05), and fine motor skills (0.89 SD; P < 0.01) compared to children in no intervention.
  • Mothers of children in the home-visit program reported less stress and depressive symptoms (–0.34 SD; P < 0.01) and less nonresponsiveness to their child (–0.92 SD; P < 0.01), significantly more reading to child and more learning materials at home compared to mothers of children who were not in a program. These mothers are also less likely to work.
  • Children in childcare centers had lower memory scores (–0.44 SD; P < 0.05) and language scores (–0.37 SD; P < 0.05) compared to children in no intervention.
  • Mothers of children in childcare centers reported significantly more depressive symptoms, more nonresponsiveness to child, fewer learning materials, and no effect on reading to child compared to mothers of children who were not in a program. These mothers worked more and had higher incomes.

  • Nutrition/health:
  • More children in childcare centers (8.8%) were underweight compared to children in no intervention (0.09 SD; P < 0.05).
  • Fewer children in home-visit program were anemic compared to no intervention (–0.215 SD; P < 0.01) but a larger proportion was stunted (0.11 SD; P < 0.05).
  • (Used SDs reported by authors rather than Cohen's d.)

  • Rosero47
  • Ecuador

  • 1906 children under age of 6 years in rural or marginalized urban, low-income households.
  • Used propensity score matching and matched children in the program and children not in the program on probability of treatment. 660 children in the treatment group and 1246 in the control group.
  • Sufficient common support.

  • Child development:
  • The Child Rescue Program includes childcare and education. The program operated 8 h a day, 5 days a week, 52 weeks a year.
  • Nutrition/health:
  • Nutritional supplementation (two meals a day).

  • Child development:
  • Receptive language (Spanish language–adapted PPVT), long-term memory (Woodcock—Johnson–Muñoz), fine motor skills (Pegboard), language skills, gross and fine motor skills, social behavior (Nelson–Ortiz), maternal depression (CES-D), home environment (HOME Inventory).
  • Nutrition/health:
  • HAZ, WAZ, presence of anemia.

  • Child development:
  • Children under 36 months of age in childcare centers scored lower on the receptive language test (–0.39 SD; P < 0.05) compared to controls.
  • All other cognitive, motor, or social developmental tests showed no significant difference.
  • Nutrition/health:
  • Children in childcare centers had a higher probability of being below height (0.17 SD; P < 0.05) compared to controls.
  • All other child health outcomes were not significant.
  • Mother's depression and responsiveness were not significantly affected but there was a significant increase of 20–22% in working and in household income of US$23–30.
  • (Used SDs reported by authors rather than Cohen's d.)

  • a Ranges given for differing effects by age (36–48 months and 49 months and older).
  • b Range given for differing effects by length of program exposure (under 15 months and 16 months or more).
  • HOME, Home Observation for Measurement of the Environment Inventory; WPPSI-III, Wechsler Preschool and Primary Scale of Intelligence—Third Edition; PPVT, Peabody Picture Vocabulary Test; PIPPS, Penn Interactive Peer Play Scale; ASQ, Ages and Stages Questionnaire; SDQ, Strengths and Difficulties Questionnaire; CES-D, Center for Epidemiological Studies—Depression Scale; WHZ, weight for height Z-score; WAZ, weight for age Z-score; HAZ, height for age Z-score; SD, standard deviation; EDI, Early Development Instrument;. d, Cohen's d effect size.

Four center-based42, 43, 45, 46 and one home-based44 program had positive effects on children's development with small-to-moderate effect sizes. Two center-based programs showed negative effects on children's development;44, 47 the parent groups41 had no effect on children's language development, although the level of stimulation in the home improved. There were inconsistent and limited benefits to weight for age in one study42 and no effect in two studies.45, 46 The home-visiting program was associated with reduced anemia levels but increased stunting.44 Four studies reported some deficits: one found participants had increased anemia but reduced wasting,43 one found more wasting,41 one found reduced weight for age,44 and another found more stunting.47

Sustainability of benefits

We found only three studies that followed the children up after a period of time. In the Jamaican study,23 children were reassessed at 7, 12, 17, and 22 years of age.48-54 At 7 years, benefits to growth were no longer apparent and cognitive benefits from stimulation or supplementation were small. No cognitive benefits from nutritional supplementation remained at 12 years, but effects of psychosocial stimulation were larger, and by ages 1752, 53 and 2254 were wide ranging (intelligence quotient, depression, violent behavior, educational attainment) and strong (Table 6).

Table 6. Long-term follow-up of studies described in Tables 2 and 4
Study and country Outcome measures Treatment effects (effect sizes)

  • Original study Grantham-McGregor et al.23 (Table 2)
  • Walker et al.48
  • Grantham-McGregor et al.49
  • Walker et al.50
  • Chang et al.51
  • Walker et al.52
  • Walker et al.53
  • Walker et al.54
  • Jamaica

  • Age 7–8: Stanford Binet, Ravens matrices, tests of memory and language, grooved pegboard, WRAT, height and weight.
  • Age 11–12: WISC-R, Ravens Matrices, language, memory, attention, WRAT, Rutter parent and teacher scales.
  • Age 17–18: WAIS IQ, Ravens Matrices, memory and language, vocabulary (PPVT), reading test, WRAT mathematics, depression, anxiety, self-esteem, antisocial behavior (self-report), attention deficit, oppositional behavior (Conners parent report).
  • Age 22: WAIS IQ, WRAT—expanded form, grade level attained, examination passed, general knowledge, depression, anxiety, social inhibition, antisocial behavior (self-report).

  • Benefits for IQ (d = 0.41) and other cognitive tests not significant individually, but stimulation groups (and supplement-only group) had better scores than control group on 13–14 of 15 tests (sign test P = 0.01). Significant benefits for perceptual motor function. No significant benefits for school achievement. No sustained effects of supplementation on growth.
  • Significant benefits for IQ (d = 0.52), reasoning ability, and vocabulary compared with control group. No benefits for two other language tests and tests of memory and attention. Suggestive of benefits for reading, spelling, and comprehension (all P < 0.1) but not mathematics. No benefits for behavior by teacher and parent reports.
  • Significant benefits to IQ (d = 0.51), vocabulary (analogies and PPVT), and reasoning ability compared with no-stimulation groups (control and supplement only). Significant benefits for reading and comprehension. No benefits for mathematics. Reduction in school dropout rate. Significant reduction in participants’ reports of symptoms of anxiety and depression and parents’ reports of attention problems. Participants reported higher self-esteem. No effect on antisocial behavior. Less oppositional behavior reported by parents (P = 0.1).
  • Significant benefits of stimulation to IQ (d = 0.6), educational attainment, general knowledge; reduced depression, social inhibition, and violent behavior.

  • Original study McKay et al.17
  • (Table 4)
  • Perez-Escamilla and Pollitt39
  • Sinisterra59
  • Colombia, Cali

  • Age 7–10 years: Height and weight measured yearly to age of 10 years.
  • Ages 98 and 112 months: WISC, grade level attained.

  • At the end of treatment at 7 years of age, the group that received four treatment periods had gained 0.6 SD in height for age and 0.7 SD in weight for age compared with the group that had received one treatment session. By age of 10 years, there were no significant differences between the groups in weight or height.
  • Attrition varied by group from 26% to 39%.
  • Difference between groups reduced. Groups that received one and two treatment periods had significantly lower IQs than groups that received three and four treatment periods. The group that received four treatment periods attained one grade level higher than children that received one treatment period.
  • Details not available.

  • Original study Waber et al.28
  • (Table 2)
  • Super et al.57
  • Super and Herrera56
  • Colombia, Bogota

Age 6 years: Preschool achievement test in mathematics, reading readiness, basic knowledge, height, and weight.

  • Benefits from supplement to height and weight maintained.
  • Supplementation benefited reading (P = 0.05) but not mathematics. Stimulation benefited reading only in boys (P = 0.07).
  • 45% loss at 6 years.

  • WRAT, Wide Range Achievement Test; WISC-R, Wechsler Intelligence Scale for Children—Revised; WAIS, Wechsler Adult Intelligence Scale; IQ, Intelligence quotient; PPVT, Peabody Picture Vocabulary Test; WAZ, weight for age Z-score; HAZ, height for age Z-score; d, Cohen's d effect size; SD, Standard deviation.

Four groups from the Bogota study28 were reassessed around 6 years of age with a preschool readiness test.55 Supplementation from pregnancy to 3 years showed benefits for reading (P < 0.05), and stimulation had marginal benefits in reading only in boys (P = 0.07); there was no significant interaction.56 These results were published only in an abstract, preventing further analyses. The children sustained their height benefits from supplementation and benefits were found for the first time in height from stimulation.57

Children from the Cali study17 were followed up 2 years after the intervention, when growth benefits were no longer apparent.39 Benefits to cognition58 were smaller but remained significant and related to number of treatment periods.59


Effects of psychosocial interventions on child development

Four efficacy trials23, 27-29 showed that the effects of stimulation on child development were similar when given independently or combined with nutrition. In only one study, stimulation combined with zinc supplementation had synergistic benefits on DQ and eye–hand coordination more than the sum of the individual interventions.26 In a further six studies,30, 34, 36-38, 40 it was possible to evaluate the additional effect on children's development from integrating psychosocial stimulation with nutrition interventions. All of these showed benefits to child development. Thus, the evidence is strong that the benefits from psychosocial stimulation are maintained when the interventions are given in combination with nutrition interventions. The child development components were mostly delivered through home visits to demonstrate stimulation activities and engage each mother in responsive play with the child.23, 26, 28, 30, 36-38 Benefits were also found when the intervention was delivered through individual play sessions at a clinic27, 40 or parent group sessions.29

Effects of nutrition intervention on children's development

It is possible to evaluate the effects of nutrition interventions for child development when given independently and combined with stimulation in five studies.23, 26, 28-30 The independent effects of the nutrition intervention were unchanged when psychosocial stimulation was added in all but one study, which involved zinc supplementation.26 In all of these studies, supplementation began before 30 months (before 24 months in all but one). In two other studies,29, 35 it was possible to evaluate the effect of adding micronutrient supplementation to stimulation. Micronutrients given with stimulation had no additional benefits to children's language in one study29 but benefits were found to several cognitive outcomes when micronutrient supplementation was given to children aged 3–6 years attending preschool.35 There was no decrease in the effects of stimulation in either study.

Effects of psychosocial intervention on nutritional and health status

There is little evidence that the child development components benefit nutrition and health outcomes, with only two studies from Bangladesh, involving severely malnourished children, showing benefits to weight gain.27, 40 One of these40 was nonrandomized and had biased loss to follow-up. In five studies adding child development to ongoing nutrition services, none showed significant detrimental effects of the existing service on health or nutrition.36-38, 40

Effects of nutritional intervention on nutritional and health status

The effects of the nutrition interventions on growth and morbidity were not changed significantly when stimulation was added. Although there are a limited number of studies, it appears likely that benefits to growth from nutritional interventions will remain when combined with child development interventions but that there will be few additional gains to nutritional outcomes from integration.

Factors modifying the effects of interventions


One study examined the effect of an integrated intervention with nutrition and child development for different durations. Children who participated for longer had greater benefits to cognitive and growth outcomes.17 The Jamaican intervention23 was conducted for 24 months and showed that independent benefits from both stimulation and supplementation on child development occurred in the first and second year so that the total benefits increased with duration. The benefits to growth, however, occurred only in the first 6 months. Similarly, in children with IDA, benefits from stimulation to mental and social–emotional development occurred in the first and second 6 months of intervention.38


Most studies involved children under 24–30 months, so we cannot examine the effect of age. However, the Cali study17 shows the potential to benefit older children in both growth and child development as the intervention began at age 42–75 months.

Nutritional status

Several of the efficacy studies targeted undernourished children including stunted23 and severely malnourished children27, 40 and children with low weight for age,26, 36, 37 as well as infants with IDA.38 All showed that the nutritionally disadvantaged children benefited from child development interventions. These findings suggest that combining child development activities with services for undernourished children would reach children likely to benefit.

Sustainability of benefits

Of the three studies that followed up children at later ages, only one had a sustained effect of supplementation on height;57 that study provided supplementation from the third trimester of pregnancy to 3 years, reinforcing the importance of this period for nutritional outcomes. Only the Jamaican study followed children through to early adulthood, with children23 reassessed at ages 7, 12, 17, and 22.48-54 Growth and cognitive benefits from nutritional supplementation were no longer evident at 12 years but effects of psychosocial stimulation on cognition were sustained,50 and by 1752, 53 and 22 years54 were also seen for educational achievement and psychological functioning. Benefits from stimulation were weakest at age of 7 years and later benefits emphasize the importance of continued follow-up when different abilities and behaviors can be assessed. The study demonstrates the potential for important benefits from child development interventions through to adulthood. The initial effects in early childhood, however, were large, (d = 0.88) and many of the other efficacy studies and the large-scale programs have demonstrated smaller effects. Significant findings do not necessarily mean they are functionally important or sustainable and effect sizes need to be considered. Future research is needed on sustainability of benefits when initial effects are small to moderate.

Program evaluations

The question for program evaluations is whether combined interventions run by routine services, and/or operating at scale, can have similar effects to those demonstrated in efficacy trials. Unfortunately, we were unable to find any program in which psychosocial stimulation was added to nutritional services at scale. This is the type of program professionals are calling for, and there is an obvious need to evaluate them. Furthermore, although the efficacy studies mainly focused on home-visiting models, most of the program evaluations were of center-based interventions.

All eight program evaluations had integrated nutrition and child development interventions, so it was not possible to identify changes in effects when separate interventions were integrated. Five interventions found benefits to the children's development, whereas two center-based programs, both in Ecuador, found some negative effects. One study of parent groups found no effect on children's language, although there were benefits to levels of stimulation provided in the home. It is difficult to estimate the average size of the benefits because results are often reported for many outcomes broken down by duration of program and age of child. There is a suggestion that duration is important, and that less than 7 months is unlikely to be beneficial.46

It is worrying that there was generally no consistent benefit to children's nutritional status, and some deficits were found in three studies.41, 44, 47 This lack of benefit occurred in spite of some programs giving two meals a day, and needs further investigation. Many of the children were older than 24 months, which may contribute to the lack of benefit in linear growth. It is likely that these mixed findings reflect the quality of the programs; however, data on program quality were generally lacking. Previous reviews of a larger number of child development interventions5, 6 found strong evidence of benefits of center-based programs on children's development, but did not assess effects on nutritional status; the Ecuadorian studies44, 47 were not available at that time. It may be relevant that the two programs that showed possible harm for development were full-day care 5 days a week with children aged from birth to 6 years. Center-based day care programs are challenging for nonprofessionals to run effectively, and it is important that they are evaluated and programs to maintain standards are put in place. Apart from program quality, the mothers were more likely to work, spent less time with their children, and had higher levels of perceived stress. The mothers also provided worse home stimulation and a reduced amount of food at home, all of which could explain the negative effects.44

Box 2. Evidence gaps in effects of integrated interventions

Evaluations of integration of child development interventions with health services.

Evaluations of integrated interventions at scale.

Long-term follow-ups of interventions with modest initial impacts.

Studies designed to show individual and combined effects.

Evaluation of different approaches to reach children 1–3 years of age.

Evaluation of effects of program quality.

Evaluation of ways to improve quality of center-based strategies at scale and use of centers for early learning to deliver health and nutrition interventions for children 3–6 years of age.

Evaluations of sustainability of benefits from integrated intervention using existing cohorts.

Identification of the essential components of child development interventions for maximum effect.

Techniques to enhance effects of nutrition interventions on both growth and development.

We only found one evaluation of a program using parent groups,41 even though this approach is often favored by NGOs. There was no benefit to children's development, and the investigator subsequently improved the conduct of the groups by inserting demonstrations and practice of play activities by the mothers with coaching. As a consequence, there were benefits to child development,29 again illustrating the importance of evaluation and quality control of programs.

Validity of findings

Most efficacy studies were randomized with pre- and posttest measures, so the findings should be internally valid. However, they generally focused on high-risk children, who were often undernourished and had poor levels of development. Thus, it is unclear whether the same results would be obtained when interventions begin before deficits appear. Most of these studies used home visiting, and thus the findings cannot be extrapolated to center-based interventions or parent groups. Furthermore, although stimulation was effective when integrated into existing services, in most studies new staff were hired to train and supervise the home visitors and in some cases to conduct the visits, so it would be misleading to conclude that integration could be done effectively without extra resources.

An important weakness of the studies—mainly in program evaluations—was the validity and administration of the child development tests. Usually little information was given about test administration, such as interobserver or test–retest reliabilities, and whether the testers were blind to intervention group. Cultural differences can affect the construct validity of established tests, and some measure of validity in the study population needs to be assessed. The choice of tests was often not justified. While logistical reasons may limit the tests that can be administered when a program is assessed on only one domain, such as language, other benefits may be missed.60 Using only mothers’ or teachers’ reports of child development is also questionable if the respondents have also been affected by the intervention.

Evidence gaps

Key areas where additional information is needed are summarized in Box 2. There is little evidence on the long-term sustainability of the benefits from efficacy studies and none from programs. In addition, greater inclusion of regions where fewer studies or programs have been implemented would be useful.

The most striking evidence gap was the lack of rigorous studies examining integrated interventions that combined psychosocial stimulation with health interventions (e.g., hand washing, bed nets, and health education). Although we originally intended to review studies in this paper examining integration of psychosocial stimulation with health or nutrition interventions, we ultimately focused solely on nutrition due to the lack of evidence. There were some examples, however. One study added a stimulation component to standard treatment for HIV in young children and found benefits for cognition;61 others added health treatments, such as deworming62 or hand washing63 to existing preschool programs.


While evidence from efficacy trials is limited and comes mainly from home-visiting interventions, the evidence is reasonably consistent. Combining nutritional and child development activities is likely to have additional benefits for young children. Synergy between nutrition and child development interventions, although theoretically plausible, has rarely been demonstrated. More information is needed, as few studies were designed to address this. Child development interventions primarily benefit developmental outcomes, whereas nutrition can benefit both development and nutritional status. In efficacy studies, adding child development to existing nutrition services usually has no negative effects on the benefits from the original service. Benefits appear to improve with duration of intervention, at least up to 3 years.

We were unable to locate any programs at scale in which the effects of integrating stimulation into health and nutrition services on children's growth and development were assessed. There is an urgent need for such studies. Nor could we locate any programs at scale where it was possible to assess the independent effects of the separate components as well as their combined effects. The integrated programs were mainly center based and most benefited children's development but not nutritional status. A few were ineffective, which is probably due to poor-quality programs. There is an urgent need to evaluate quality of programs and to establish quality-control mechanisms.

Conflicts of interest

The authors declare no conflicts of interest.