Differential influences of early growth and social factors on young children's cognitive performance in four low-and-middle-income birth cohorts (Brazil, Guatemala, Philippines, and South Africa)

Background

Studies relating childhood cognitive development to poor linear growth seldom take adequate account of social conditions related to both, leading to a focus on nutrition interventions. We aimed to assess the roles of both biological and social conditions in determining early childhood cognition, mediated by birthweight and early linear growth.

Methods

After exploratory structural equation modelling to identify determining factors, we tested direct and indirect paths to cognitive performance through birthweight and child height-for-age at 2 years, assessed between 4 and 8.5 years of age among 2448 children in four birth cohort studies in low-and-middle-income countries (Brazil, Guatemala, Philippines and South Africa). Determinants were compared across the cohorts.

Findings

Three factors yielded excellent fit, comprising birth endowment (primarily maternal age and birth order), household resources (crowding, dependency) and parental capacity (parental education). We estimated their strength together with maternal height in determining cognitive performance. Percentage shares of total effects of the four determinants show a marked transition from mainly biological determinants of birth weight (birth endowment 34%) and maternal height (30%) compared to household resources (25%) and parental capacity (11%), through largely economic determinants of height at 2 years (household resources (60%) to cognitive performance being predominantly determined by parental capacity (64%) followed by household resources (29%). The largely biological factor, birth endowment (maternal age and birth order) contributed only 7% to childhood cognitive performance and maternal height was insignificant. In summary, the combined share of social total effects (household resources and parental capacity) rises from 36∙2% on birth weight, to 78∙2% on height for age at 24 m, and 93∙4% on cognitive functioning.

Interpretation

Across four low- and middle-income contexts, cognition in childhood is influenced more by the parental capacity of families and their economic resources than by birth weight and early linear growth. Improving children's cognitive functioning requires multi-sectoral interventions to improve parental education and enhance their economic wellbeing, interventions that are known to improve also early childhood growth.

•

We aimed to investigate separate and combined biological and social determination of young children’s cognitive performance.

•

We used path analysis of longitudinal data from birth cohort studies in four differing low-and-middle countries.

•

We distinguished biological and social factors, as well as household resources from parental capacity.

•

Biological factors determine birthweight, 2-year height depends on social factors, and the latter drive child cognitive performance.

•

No single domain intervention provides both necessary and sufficient support for young children’s unfolding development.

Early life diarrhoea and later blood pressure in a developing country: the 1982 Pelotas (Brazil) birth cohort study

BACKGROUND

It has recently been hypothesised that acute dehydration in early childhood may "programme" increased blood pressure via salt retention. We examined whether there was an association between episodes of diarrhoea (a proxy for acute dehydration) and later measured blood pressure.

METHODS

In the 1982 Pelotas birth cohort study (Brazil), parents/carers reported hospital admissions for diarrhoea in the first 12 and 20 months of study members' lives. Blood pressure was subsequently measured directly in adolescence (aged 15, 18, 19 years) and early adulthood (aged 23 years).

RESULTS

We found no evidence of an association between diarrhoea in the first 12 months of life and blood pressure measured at any point in adolescence or early adulthood. These findings were unchanged after adjustment for a range of covariates. Equally null results were apparent when diarrhoea admissions in the first 20 months of life, access to home sanitation and use of piped water were the exposures of interest.

CONCLUSIONS

Early life proxies for dehydration and diarrhoea were unrelated to later blood pressure in this examination, the most comprehensive to date, of the potential association.

Can improvements in breast-feeding practices reduce neonatal mortality in developing countries?

OBJECTIVE

to review the literature on the relationship between breast-feeding practices in the first month of life and neonatal mortality.

METHODS

Medline and Cochrane databases were searched using the keywords breastfeeding, and neonatal mortality, supplemented with additional searches using the keywords developing countries, colostrum, infant feeding and infant mortality, hypoglaecemia, hypothermia, breastfeeding practices, and suckling.

FINDINGS

breast feeding helps prevent hypothermia and hypoglycaemia in newborn babies, which are contributory causes of early neonatal deaths especially among low birth weight and premature babies. During the late neonatal period, most deaths in developing countries are due to infections such as sepsis, acute respiratory tract infection, meningitis, omphalitis and diarrhoea. Feeding colostrum and breast feeding, especially exclusive breast feeding, protects against such deaths.

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

in most developing countries, nearly all women breast feed in the first month of life, but often breast feeding is delayed beyond the first hour after birth, and exclusive breast feeding is not usually practised. Policies and training of staff of maternity centres and hospitals can encourage early initiation of breast feeding and exclusive breast feeding. Midwives can support community-based efforts to support exclusive breast feeding. Breast feeding plays an important role in reducing neonatal mortality and should be strongly emphasised by programmes attempting to reduce neonatal mortality.

A follow-up study of Toxoplasma gondii infection in southern Brazil

PURPOSE

To understand better the natural history of ocular toxoplasmosis by reexamining a well-characterized population in Southern Brazil.

METHODS

Ophthalmological examination and serologic tests for Toxoplasma gondii infection were performed in 1997 on 383 individuals who had undergone the same evaluation in 1990.

RESULTS

Of 109 seronegative subjects in 1990, 21 (19.3%) became seropositive by 1997, and 2 (1.5% of previously seronegative patients; 9.5% of those known to have seroconverted) developed ocular toxoplasmosis. Seroconversion occurred more frequently in individuals under 17 years of age (16 of 46 patients, 34.8%) than in those greater than 17 years of age (5 of 63 patients, 7.9%; p = 0.002). Of 131 seropositive individuals who did not have ocular lesions in 1990, 11 (8.3%) had typical toxoplasmic lesions in 1997. Of the 13 individuals with non-specific hyperpigmented small retinal lesions in 1990, 3 (23%) presented with typical lesions in 1997.

CONCLUSIONS

Acquired T. gondii infection can result in late development of ocular lesions. Small, non-specific hyperpigmented retinal lesions may represent sites of T. gondii infection in seropositive individuals.

The Latin American trial of psychosocial support during pregnancy: effects on mother's wellbeing and satisfaction. Latin American Network For Perinatal and Reproductive Research (LANPER)

A randomized controlled trial including 2235 women at high risk of low birthweight was conducted in four Latin American institutions. The objective of this trial was to evaluate a psychosocial support intervention during pregnancy aimed at improving perinatal health and mothers' psychosocial conditions. The core of the intervention was four to six home visits where emotional support, counseling and strengthening of the woman's social network was provided. Outcomes were measured at 36 weeks of pregnancy, post-partum and 40 days after delivery. The intervention was not successful in either altering women's perception of social support and satisfaction with the reproductive experience, as well as maternal and newborn's health care. It is concluded that although high levels of psychosocial distress during pregnancy may play an independent role in determining adverse pregnancy outcomes, this adverse effect does not appear to be ameliorated by psychosocial interventions conducted only during pregnancy, particularly those of a magnitude that can be realistically implemented (in content and frequency) at public care services in most developing countries.

Impact of health education during pregnancy on behavior and utilization of health resources. Latin American Network for Perinatal and Reproductive Research

OBJECTIVE

Our purpose was to assess whether an intervention in the education of the mother and the support person involves a change in health-related behavior and use of health facilities.

STUDY DESIGN

A randomized, controlled trial was conducted in four cities of Latin America on pregnant women at risk. Half of them (n = 1115) received a home intervention of four to six visits dealing with psychosocial support and education about health-related habits, alarm signs, hospital facilities, antismoking and antialcohol programs, and a reinforcement of adequate health services utilization for the pregnant woman and a support person. The control group (n = 1120) received routine prenatal care.

RESULTS

The distribution of risk factors and demographic, obstetric, and psychologic characteristics at baseline was similar in both groups. Women in the intervention group showed a statistically significant better knowledge of seven of the nine alarm signs considered and of two of the three labor-onset signs required. No differences between groups were observed in improvement on diet, cigarette and alcohol consumption, maternal physical strain, lactation at 40 days postpartum, and utilization of health facilities.

CONCLUSIONS

An intervention of psychosocial support and health education during pregnancy failed to show any benefit on perinatal outcome, health-related behavior, or utilization of health facilities.

The Latin American trial of psychosocial support during pregnancy: a social intervention evaluated through an experimental design

Perinatal health problems are a public health priority in Latin America. Among the identified risk factors, psychological and social conditions play a crucial role. However, care during pregnancy and delivery in the region is usually hospital-centered and does not address women's psychological and social conditions. The preeminence of research on perinatal health, along with the necessity for testing interventions that represent alternative models to improve women's health, gave the Latin American Network for Perinatal and Reproductive Research grounds to develop a multicenter randomized controlled trial to evaluate a program of social support and health education during pregnancy. The conceptual framework for this study was based on an ecological model of social support, i.e. a model in which social support and health education play a synergistic role and are meant to modify stressful situations and negative health-related behaviors. The target population consisted of women attending obstetric hospitals before the 22nd gestational week, at high psychological and social risk (n = 2236). The intervention consisted of four to six home visits, carried out by social workers, and had four main components: the reinforcement of pregnant women's social support network, emotional support, health education, and the improvement of health services utilization. The main foci of the intervention were determined after an ethnographic study was carried out to identify stress-producing situations and needs for support during pregnancy. Besides the home visits, the program also offered a hot-line, an office in the hospital, a specially designed poster and booklet, and a 'guided tour' of the health institution. Since this was a multicenter trial, the program's standardization was a crucial methodological aspect that was achieved through the training course for the home-visitors team. Biological and psychosocial outcomes were measured in both experimental and control groups at the 36th week of gestational age, post-partum and at the 40th day after delivery. The attributes of the multicenter population showed an important variability, reflecting differences in the countries or hospitals' population prevalent attributes. The results of the program's implementation were analyzed, demonstrating that home visitors adapted topics discussed during the interviews to the women's conditions and the stage of pregnancy during which the visit took place.(ABSTRACT TRUNCATED AT 400 WORDS)

A randomized trial of psychosocial support during high-risk pregnancies. The Latin American Network for Perinatal and Reproductive Research

BACKGROUND

It is often suggested that psychological and social support and health education for women at high risk for delivering a low-birth-weight infant can improve the outcomes of pregnancy, but the evidence is inconclusive. We undertook this prospective trial to evaluate a program of home visits designed to provide psychosocial support during pregnancy.

METHODS

At four centers in Latin America, 2235 women at higher-than-average risk for delivering a low-birth-weight infant were recruited before the 20th week of pregnancy. The women were randomly assigned either to an intervention group (n = 1115) that received four to six home visits from a nurse or social worker in addition to routine prenatal care or to a control group (n = 1120) that received only routine prenatal care (with a mean of eight prenatal visits). The principal measures of outcome were low birth weight (< 2500 g), preterm delivery (< 37 weeks of gestation), and specified categories of maternal and neonatal morbidity.

RESULTS

The women who received the home visits as well as routine prenatal care had outcomes that differed little from those of the women who received only routine care. The risks of low birth weight (odds ratio for the intervention group as compared with the control group, 0.93; 95 percent confidence interval, 0.68 to 1.28), preterm delivery (odds ratio, 0.88; 95 percent confidence interval, 0.67 to 1.16), and intrauterine growth retardation (odds ratio, 1.08; 95 percent confidence interval, 0.83 to 1.40) were similar in the two groups. There was no evidence that the intervention had any significant effect on the type of delivery, the length of hospital stay, perinatal mortality, or neonatal morbidity in the first 40 days. There was no protective effect of the psychosocial-support program even among the mothers at highest risk.

CONCLUSIONS

Interventions designed to provide psychosocial support and health education during high-risk pregnancies are unlikely to improve maternal health or to reduce the incidence of low birth weight among infants.

Coffee during pregnancy: a reproductive hazard?

Coffee is consumed in large quantities worldwide and any adverse effects would likely have important public health consequences. Because of the widespread exposure to coffee and other caffeine-containing beverages and because teratogenic effects of caffeine have been recorded in several species since 1960, women are concerned that there may be reason to limit their intake of coffee when pregnant. Several human studies on birth defects have been conducted and the overall results do not implicate coffee as a likely human teratogen. However, there is some evidence that consumption of three or more cups of coffee per day may have a modest effect on lowering infant birth weight. Studies of coffee consumption and increased rates of spontaneous abortion and delayed time to conception are inconsistent and conclusions cannot yet be drawn.