Ernesto Pollitt

Child development: risk factors for adverse outcomes in developing countries

Poverty and associated health, nutrition, and social factors prevent at least 200 million children in developing countries from attaining their developmental potential. We review the evidence linking compromised development with modifiable biological and psychosocial risks encountered by children from birth to 5 years of age. We identify four key risk factors where the need for intervention is urgent: stunting, inadequate cognitive stimulation, iodine deficiency, and iron deficiency anaemia. The evidence is also sufficient to warrant interventions for malaria, intrauterine growth restriction, maternal depression, exposure to violence, and exposure to heavy metals. We discuss the research needed to clarify the effect of other potential risk factors on child development. The prevalence of the risk factors and their effect on development and human potential are substantial. Furthermore, risks often occur together or cumulatively, with concomitant increased adverse effects on the development of the worlds poorest children.

Reversal of developmental delays in iron-deficient anaemic infants treated with iron

Iron-deficient anaemic infants perform worse in tests of mental and motor development than do iron-sufficient infants of a comparable age. A randomised, double-blind trial was done to monitor the effects of iron supplementation on performance in the Bayley scales of mental and motor development among 12-18-month-old infants in Indonesia. Iron-deficient anaemic infants (n = 50) were assigned randomly to receive dietary ferrous sulphate or placebo for 4 month. Similar treatment randomisation was done among nonanaemic iron-deficient (n = 29) and iron-sufficient (n = 47) infants. Before intervention, the mean mental and motor scores of the iron-deficient anaemic infants were significantly (p < 0.01) lower than those of the nonanaemic iron-deficient and iron-sufficient classes. After intervention, developmental delays were reversed among iron-deficient anaemic infants who had received iron but they remained the same among placebo-treated iron-deficient anaemic infants. Neither ferrous sulphate nor placebo had significant effects on the scores of the other two iron-status classes. The poor performance of 12-18-month-old iron-deficient anaemic infants in the Bayley scales of mental and motor development can be improved to the level of performance of iron-sufficient infants by treatment with ferrous sulphate.

Early supplementary feeding and cognition : effects over two decades

The study reported in this Monograph of the effects of early supplementary feeding on cognition included two data collection periods: a longitudinal investigation spanning the years 1969-1977 and a cross-sectional follow-up carried out in 1988-1989. The study was conducted in four rural villages in Guatemala and compared the differential effects of exposure in childhood (0-7 years) to an Atole supplement (11.5 g of protein; 163 kcal) or a Fresco supplement (59 kcal) on performance on a battery of psychoeducational and information-processing tests in adolescence and young adulthood (11-24 years). In this report, particular attention is given to a cohort of subjects who were exposed to the supplement prenatally and during at least the first 2 years of postnatal life. Data on this subsample are contrasted with those on a cohort of subjects who received the supplement only after 24 months of life. The Monograph also reports results from an analysis of the supplementation effects in infancy and early childhood. Consistent differences between groups on the psychoeducational tests were observed. Adolescents from Atole villages scored significantly higher on tests of knowledge, numeracy, reading, and vocabulary than Fresco subjects. Atole was also associated with a faster reaction time in information-processing tasks. Significant interactions helped identify two groups who benefited more from the Atole treatment: those at the lowest levels of socioeconomic status and those who attained the highest levels of primary schooling. The consistent differences in test performance established in the follow-up assessment contrast sharply with the few and less pronounced between-group differences observed in the infancy and preschool periods. After close scrutiny of alternative hypotheses, it is concluded that nutritional differences provide the strongest explanation for the test performance differences observed in the follow-up between the subjects exposed to the Atole and those exposed to the Fresco supplement.

Effects of iron supplementation and anthelmintic treatment on motor and language development of preschool children in Zanzibar: double blind, placebo controlled study

Abstract Objective: To measure the effects of iron supplementation and anthelmintic treatment on iron status, anaemia, growth, morbidity, and development of children aged 6–59 months. Design: Double blind, placebo controlled randomised factorial trial of iron supplementation and anthelmintic treatment. Setting: Community in Pemba Island, Zanzibar. Participants: 614 preschool children aged 6–59 months. Main outcome measures: Development of language and motor skills assessed by parental interview before and after treatment in age appropriate subgroups. Results: Before intervention, anaemia was prevalent and severe, and geohelminth infections were prevalent and light—Plasmodium falciparum infection was nearly universal. Iron supplementation significantly improved iron status, but not haemoglobin status. Iron supplementation improved language development by 0.8 (95% confidence interval 0.2 to 1.4) points on the 20 point scale. Iron supplementation also improved motor development, but this effect was modified by baseline haemoglobin concentrations (P=0.015 for interaction term) and was apparent only in children with baseline haemoglobin concentrations <90 g/l. In children with a baseline haemoglobin concentration of 68 g/l (one standard deviation below the mean value), iron treatment increased scores by 1.1 (0.1 to 2.1) points on the 18 point motor scale. Mebendazole significantly reduced the number and severity of infections caused by Ascaris lumbricoides and Trichuris trichiura, but not by hookworms. Mebendazole increased development scores by 0.4 (−0.3 to 1.1) points on the motor scale and 0.3 (−0.3 to 0.9) points on the language scale. Conclusions: Iron supplementation improved motor and language development of preschool children in rural Africa. The effects of iron on motor development were limited to children with more severe anaemia (baseline haemoglobin concentration <90 g/l). Mebendazole had a positive effect on motor and language development, but this was not statistically significant. What is already known on this topic Iron is needed for development and functioning of the human brain Anaemic children show developmental delays, but it is not yet clear whether iron deficiency causes these deficits or whether iron supplementation can reverse them Helminth infections in schoolchildren are associated with cognitive deficits, but few studies have been made of helminth infection and early child development What this study adds Low doses of oral iron supplementation given daily improved language development in children aged 1–4 years in Zanzibar Iron supplementation improved motor development, but only in children with initial haemoglobin concentrations below 90 g/l The effects of routine anthelmintic treatment on motor and language milestones were positive, but non-significant, with our sample size

Does breakfast make a difference in school

This article reviews selectively the literature on the effects of breakfast on cognition and school performance. The focus is on studies published in refereed journals after 1978 that tested those effects on well-nourished and nutritionally at-risk children. In at-risk subjects (defined by clinical history and anthropometry), a morning and overnight fast had adverse effects on cognition, particularly the speed of information retrieval in working memory. Contradictions in the data from different studies prevent definitive conclusions on whether well-nourished children experience similar functional deficits. Nonetheless, available information suggests that brain function is sensitive to short-term variations in the availability of nutrient supplies. Moreover, well-conducted evaluations suggest that the availability of feeding programs in public schools throughout the academic year increases the probability that children will eat breakfast and improve their educational status.

Infant feeding policies in maternity wards and their effect on breast-feeding success : an analytical overview

OBJECTIVES The purpose of this review is to examine the plausibility of a causal relationship between maternity ward practices and lactation success. METHODS Studies were located with MEDLINE, from our personal files, and by contacting researchers working in this field. Of the 65 studies originally reviewed, 18 met our inclusion criteria (i.e., hospital-based intervention, experimental design with randomization procedures, or quasi-experimental design with adequate documentation). RESULTS Meta-analysis indicated that commercial discharge packs had an adverse effect on lactation performance. The impact of early mother-infant contact on lactation success was unclear. Rooming-in and breast-feeding guidance in a rooming-in context had a beneficial impact on breast-feeding among primiparae. Breast-feeding on demand was positively associated with lactation success. In-hospital formula supplementation of 48 mL per day was not associated with poor breast-feeding performance. CONCLUSIONS Hospital-based breast-feeding interventions can have a beneficial effect on lactation success, particularly among primiparous women.

Iron deficiency and educational achievement in Thailand

This double-blind clinical trial was conducted in Thailand to assess the impact of iron treatment on the IQ and educational attainment of 1358 9-11-y-old children. The children were classified into one of three groups: iron replete, iron depleted, and iron-deficient anemic. The Raven Progressive Matrices was used to measure IQ. A Thai language and a math test were administered to assess school attainment. A 50-mg/d tablet of ferrous sulphate was given for 2 wk and a 100 mg/d tablet, for 14 wk. An anthelminthic drug was given on the day of the blood test before treatment and 3 mo after the intervention started. There is evidence of a positive association between iron status and IQ and a language school achievement test but there is no support for the internal validity of the hypothesis that this association is causal.

Iron deficiency and behavior

The literature bearing on the behavioral correlates of sideropenia in animals and man is reviewed. There is evidence to support the contention that sideropenia, per se, is causally related to the subjective complaints of the iron-deficient and/or anemic individual. And, although important biochemical pathways involving electron transport, catecholamine catabolism, and porphyrin synthesis have been shown to be deranged in iron-deficient animals and human beings, the role of these alterations in any putative behavioral aberration is conjectural at present. Given the high prevalence of iron deficiency in the worlds population, these issues should be addressed by appropriate biochemical and psychologic studies in animals and human beings.

Effects of iron deficiency on attention and learning processes in preschool children: Bandung, Indonesia

A double-blind clinical trial was conducted in Indonesia to assess effects of iron supplementation on performance of iron-depleted and iron-deficient anemic children in discrimination and oddity learning tasks. Half these children received elemental Fe for 8 wk; the others received a placebo. There were significant changes from pre- to postintervention evaluations in ferritin, transferrin saturation, free erythrocyte protoporphyrin, and hemoglobin among the anemic and iron-depleted children; no changes were observed among the placebos or any of the iron-replete children. The magnitude of hematological changes in anemic children treated with iron was small; yet, after treatment the childrens mean ferritin, transferrin saturation, and hemoglobin values were above the cutoff points used for the definition of iron-deficiency anemia (IDA). Pre- and posttreatment psychological test data show that IDA produces alterations in cognitive processes related to visual attention and concept acquisition, alterations reversed with iron treatment.

Adverse effect of iron supplementation on weight gain of iron-replete young children

The efficacy of iron supplementation for iron-deficient subjects is in no doubt. However, the assumption that iron supplementation of iron-replete subjects is harmless may not be valid. We have studied the effect of iron supplementation on growth rate in 47 iron-sufficient young children (12-18 months) in Indonesia. The children were randomly assigned either ferrous sulphate (3 mg/kg daily) or placebo every day for 4 months. Before treatment the length, weight, and arm circumference of the two groups were similar. During the 4 months of supplementation the rate of weight gain was significantly greater in the placebo group than in the iron-supplemented group (0.106 [SE 0.010] vs 0.070 [0.011] kg every 2 weeks, p = 0.02). The rates of gain in length and arm circumference did not differ significantly by treatment. There were no differences between the groups in rates of respiratory and gastrointestinal infections. These results suggest that iron supplementation of iron-replete children may retard their growth.