Reynaldo Martorell

Strategies to avoid the loss of developmental potential in more than 200 million children in the developing world.

This paper is the third in the Child Development Series. The first paper showed that more than 200 million children under 5 years of age in developing countries do not reach their developmental potential. The second paper identified four well-documented risks: stunting, iodine deficiency, iron deficiency anaemia, and inadequate cognitive stimulation, plus four potential risks based on epidemiological evidence: maternal depression, violence exposure, environmental contamination, and malaria. This paper assesses strategies to promote child development and to prevent or ameliorate the loss of developmental potential. The most effective early child development programmes provide direct learning experiences to children and families, are targeted toward younger and disadvantaged children, are of longer duration, high quality, and high intensity, and are integrated with family support, health, nutrition, or educational systems and services. Despite convincing evidence, programme coverage is low. To achieve the Millennium Development Goals of reducing poverty and ensuring primary school completion for both girls and boys, governments and civil society should consider expanding high quality, cost-effective early child development programmes.

Effect of a nutrition intervention during early childhood on economic productivity in Guatemalan adults

BACKGROUND Substantial, but indirect, evidence suggests that improving nutrition in early childhood in developing countries is a long-term economic investment. We investigated the direct effect of a nutrition intervention in early childhood on adult economic productivity. METHODS We obtained economic data from 1424 Guatemalan individuals (aged 25-42 years) between 2002 and 2004. They accounted for 60% of the 2392 children (aged 0-7 years) who had been enrolled in a nutrition intervention study during 1969-77. In this initial study, two villages were randomly assigned a nutritious supplement (atole) for all children and two villages a less nutritious one (fresco). We estimated annual income, hours worked, and average hourly wages from all economic activities. We used linear regression models, adjusting for potentially confounding factors, to assess the relation between economic variables and exposure to atole or fresco at specific ages between birth and 7 years. FINDINGS Exposure to atole before, but not after, age 3 years was associated with higher hourly wages, but only for men. For exposure to atole from 0 to 2 years, the increase was US

The Impact of Improving Nutrition During Early Childhood on Education Among Guatemalan Adults

0.67 per hour (95% CI 0.16-1.17), which meant a 46% increase in average wages. There was a non-significant tendency for hours worked to be reduced and for annual incomes to be greater for those exposed to atole from 0 to 2 years. INTERPRETATION Improving nutrition in early childhood led to substantial increases in wage rates for men, which suggests that investments in early childhood nutrition can be long-term drivers of economic growth.

Adult consequences of growth failure in early childhood

Using a longitudinal survey from rural Guatemala, we examine the effect of an early childhood nutritional intervention on adult educational outcomes. An intent-to-treat model yields substantial effects of an experimental intervention that provided highly nutritious food supplements to children, a quarter century after it ended: increases of 1.2 grades completed for women and one quarter SD on standardised reading comprehension and non-verbal cognitive ability tests for both women and men. Two-stage least squares results that endogenise the actual supplement intakes corroborate these magnitudes. Improving the nutrient intakes of very young children can have substantial, long-term, educational consequences.

Effect of Zinc on Efficacy of Iron Supplementation in Improving Iron and Zinc Status in Women

Background: Growth failure is associated with adverse consequences, but studies need to control adequately for confounding. Objective: We related height-for-age z scores (HAZs) and stunting at age 24 mo to adult human capital, marriage, fertility, health, and economic outcomes. Design: In 2002–2004, we collected data from 1338 Guatemalan adults (aged 25–42 y) who were studied as children in 1969–1977. We used instrumental variable regression to correct for estimation bias and adjusted for potentially confounding factors. Results: A 1-SD increase in HAZ was associated with more schooling (0.78 grades) and higher test scores for reading and nonverbal cognitive skills (0.28 and 0.25 SDs, respectively), characteristics of marriage partners (1.39 y older, 1.02 grade more schooling, and 1.01 cm taller) and, for women, a higher age at first birth (0.77 y) and fewer number of pregnancies and children (0.63 and 0.43, respectively). A 1-SD increase in HAZ was associated with increased household per capita expenditure (21%) and a lower probability of living in poverty (10 percentage points). Conversely, being stunted at 2 y was associated with less schooling, a lower test performance, a lower household per capita expenditure, and an increased probability of living in poverty. For women, stunting was associated with a lower age at first birth and higher number of pregnancies and children. There was little relation between either HAZ or stunting and adult health. Conclusion: Growth failure in early life has profound adverse consequences over the life course on human, social, and economic capital.

Does Childhood Diarrhea Influence Cognition Beyond the Diarrhea-Stunting Pathway?

Iron and zinc may interact in micronutrient supplements and thereby decrease efficacy. We investigated interactive effects of combined zinc and iron supplementation in a randomized controlled trial conducted in 459 Guatemalan women. Four groups were supplemented for 12 weeks: (1) weekly iron and folic acid (IFA); (2) weekly IFA and 30 mg zinc; (3) daily IFA; (4) daily IFA and 15 mg zinc. Effects were assessed by generalized linear regression. Baseline hemoglobin (Hb) concentration was 137.4 ± 15.5 g/L, 13% were anemic and 54% had zinc deficiency. Hb cconcentrations were similar by supplement type, but Hb concentrations improved significantly in anemic women at baseline (increase of 21.8 g/L). Mean percentage changes in serum ferritin were significantly higher in daily compared to weekly supplemented groups (86% versus 32%). The addition of zinc to IFA supplements had no significant impact on iron or zinc status. In conclusion, adding zinc to IFA supplements did not modify efficacy on iron status or improve zinc status, but daily supplementation was more efficacious than weekly in improving iron stores.

Height-for-age z scores increase despite increasing height deficits among children in 5 developing countries

Background Diarrhea is a leading cause of morbidity among children under 5 years of age in low- and middle-income countries yet the additional effects and sequelae, such as cognitive impairment associated with diarrhea, have not been quantified. Methods We quantified the association between diarrhea prevalence and cognitive outcomes while controlling for linear growth in 4 study populations. Cognition was assessed using different methods across sites and was expressed in standardized units. We built linear regression models for each study with standardized cognitive score as the outcome and diarrhea prevalence as the main predictor variable. We then conducted meta-analyses of the regression coefficients to generate pooled estimates of the association between diarrhea prevalence and cognition whilst controlling for anthropometric status and other covariates. Results Diarrhea was not a significant predictor of cognitive score in any site in the regression models or in the meta-analyses (Coefficient = 0.07; 95% CI: −0.1, 0.2). The length for age Z- score was negatively related to cognition in all sites (0.18; 95% CI: 0.14, 0.21), with coefficients remarkably similar across sites (Coefficient Range: 0.168–0.186). Conclusions We did not demonstrate an association between diarrhea and cognition with stunting included in the model. The links between diarrhea, stunting, and cognition provide additional rationale for accelerating interventions to reduce diarrhea.

The human capital study 2002-04: tracking, data collection, coverage, and attrition.

BACKGROUND Growth failure remains a persistent challenge in many countries, and understanding child growth patterns is critical to the development of appropriate interventions and their evaluation. The interpretation of changes in mean height-for-age z scores (HAZs) over time to define catch-up growth has been a subject of debate. Most studies of child growth have been cross-sectional or have focused on children through age 5 y. OBJECTIVE The aim was to characterize patterns of linear growth among individuals followed from birth into adulthood. DESIGN We compared HAZs and difference in height (cm) from the WHO reference median at birth, 12 mo, 24 mo, mid-childhood, and adulthood for 5287 individuals from birth cohorts in Brazil, Guatemala, India, the Philippines, and South Africa. RESULTS Mean HAZs were <0 at birth in the 3 cohorts with data and ranged from -0.6 (Brazil) to -2.9 (Guatemala) at age 24 mo. Between 24 mo and mid-childhood, HAZ values increased by 0.3-0.5 in South Africa, Guatemala, and the Philippines and were unchanged in Brazil and India. Between mid-childhood and adulthood, mean HAZs increased in all cohorts but remained <0 in adulthood [mean range: -0.3 (Brazil) to -1.8 (Guatemala and Philippines)]. However, from 24 mo to adulthood, height differences from the reference median became greater. CONCLUSIONS From age 2 y to adulthood, mean HAZs increased, even though height deficits relative to the reference median also increased. These 2 metrics may result in different interpretations of the potential for and the impact of catch-up growth in height.

Schooling, educational achievement, and cognitive functioning among young Guatemalan adults.

Between 2002 and 2004, the Institute of Nutrition of Central America and Panama (INCAP), in collaboration with Emory University, the International Food Policy Research Institute (IFPRI), and the University of Pennsylvania, re-surveyed young Guatemalan adults who had, as children, been participants in a nutrition supplementation trial conducted by INCAP between 1969 and 1977. This “Human Capital Study 2002–04” complements and extends data obtained in previous studies by collecting new information on measures of physical health and well-being, schooling and cognitive ability, wealth, consumption and economic productivity, and marriage and fertility histories. This paper describes the study domains and data collection procedures. Among 2,393 members of the original sample, 1,856 (77%) were targets for enrollment. Response rates varied by gender, current place of residence, and domain of data collection, with 80% of males and 89% of females completing at least one data collection instrument. Attrition was not random and appears to be associated with a number of initial characteristics of individuals and their households that should be controlled for in future analyses. We conclude that data collection was successful and data quality is high, facilitating the successful undertaking of our planned investigation of important study hypotheses.

Effectiveness evaluation of the food fortification program of Costa Rica: impact on anemia prevalence and hemoglobin concentrations in women and children

Quantity and quality of schooling obtained and the resulting skills and knowledge acquired are important components of human capital. We describe the distribution of selected measures of schooling, educational achievement, and cognitive functioning among individuals who participated as children in a nutrition supplementation trial in Guatemala and were followed up in 2002–04. Among 1,469 respondents (response rate 80%), who were 26–41 years of age in 2003, more than 90% of men and women had attended at least some school; more than half of men and more than one-third of women had completed sixth grade. Schooling attainment of both men and women has increased across birth cohorts but the schooling gap between men and women has increased. Parental socioeconomic status, as measured in 1975, is a strong predictor of schooling attainment. Basic literacy is high among those studied, with more than 80% able to read simple sentences. The gap in educational achievement favoring men narrowed across birth cohorts due to increases among younger women. The greater performance among men on the Ravens Progressive Matrices test persisted despite increased scores in the younger birth cohorts for both men and women. Migrants to Guatemala City have completed more years of school and scored higher on the tests of educational achievement and cognitive functioning than have cohort members who have remained in the study villages.