Highly prevalent conditions with multiple and complex underlying etiologies are a challenge to public health. Undernutrition, for example, affects 20% of children in the developing world. The cause and consequence of poor nutrition are multifaceted. Undernutrition has been associated with half of all deaths worldwide in children aged <5 years; in addition, its pernicious long-term effects in early childhood have been associated with cognitive and physical growth deficits across multiple generations and have been thought to suppress immunity to further infections and to reduce the efficacy of childhood vaccines. The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health (MAL-ED) Study, led by the Fogarty International Center of the National Institutes of Health and the Foundation for the National Institutes of Health, has been established at sites in 8 countries with historically high incidence of diarrheal disease and undernutrition. Central to the study is the hypothesis that enteropathogen infection contributes to undernutrition by causing intestinal inflammation and/or by altering intestinal barrier and absorptive function. It is further postulated that this leads to growth faltering and deficits in cognitive development. The effects of repeated enteric infection and undernutrition on the immune response to childhood vaccines is also being examined in the study. MAL-ED uses a prospective longitudinal design that offers a unique opportunity to directly address a complex system of exposures and health outcomes in the community-rather than the relatively rarer circumstances that lead to hospitalization-during the critical period of development of the first 2 years of life. Among the factors being evaluated are enteric infections (with or without diarrhea) and other illness indicators, micronutrient levels, diet, socioeconomic status, gut function, and the environment. MAL-ED aims to describe these factors, their interrelationships, and their overall impact on health outcomes in unprecedented detail, and to make individual, site-specific, and generalized recommendations regarding the nature and timing of possible interventions aimed at improving child health and development in these resource-poor settings.

Multilevel models were used to account for the multilevel structure of the data. Living in lower income neighbourhoods was generally associated with decreased energy adjusted intake of fruits, vegetables, fish, and increased intake of meat. Patterns generally persisted after adjustment for individual level income, but were often not statistically significant. Inconsistent associations were recorded for the intake of saturated fat, polyunsaturated fat, and cholesterol. Overall, individual level income was a more consistent predictor of diet than neighbourhood income. Conclusion-Despite limitations in the definition and characterisation of neighbourhoods, this study found consistent (albeit small) diVerences across neighbourhoods in food intake, suggesting that more in depth research into potential neighbourhood level determinants of diet is warranted. (J Epidemiol Community Health 1999;53:55-63) Over the past three decades, numerous studies conducted in industrialised nations have documented higher coronary heart disease incidence, prevalence, and mortality in the lower than in the higher social classes.

The overall goal of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study is to evaluate the roles of repeated enteric infection and poor dietary intakes on the development of malnutrition, poor cognitive development, and diminished immune response. The use of 8 distinct sites for data collection from Latin America, sub-Saharan Africa, and South Asia allow for an examination of these relationships across different environmental contexts. Key to testing study hypotheses is the collection of appropriate data to characterize the dietary intakes and nutritional status of study children from birth through 24 months of age. The focus of the current article is on the collection of data to describe the nature and adequacy of infant feeding, energy and nutrient intakes, and the chosen indicators to capture micronutrient status in children over time.

Background Environmental enteric dysfunction (EED) is thought to increase the risk of micronutrient deficiencies, but few studies adjust for dietary intakes and systemic inflammation. Objective We tested whether EED is associated with micronutrient deficiency risk independent of diet and systemic inflammation, and whether it mediates the relation between intake and micronutrient status. Methods Using data from 1283 children in the MAL-ED (Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health) birth cohort we evaluated the risk of anemia, low retinol, zinc, and ferritin, and high transferrin receptor (TfR) at 15 mo. We characterized gut inflammation and permeability by myeloperoxidase (MPO), neopterin (NEO), and α-1-antitrypsin (AAT) concentrations from asymptomatic fecal samples averaged from 9 to 15 mo, and averaged the lactulose:mannitol ratio z-score (LMZ) at 9 and 15 mo. Nutrient intakes from complementary foods were quantified monthly from 9 to 15 mo and densities were averaged for analyses. α-1-Acid glycoprotein at 15 mo characterized systemic inflammation. Relations between variables were modeled using a Bayesian network. Results A greater risk of anemia was associated with LMZ [1.15 (95% CI: 1.01, 1.31)] and MPO [1.16 (1.01, 1.34)]. A greater risk of low ferritin was associated with AAT [1.19 (1.03, 1.37)] and NEO [1.22 (1.04, 1.44)]. A greater risk of low retinol was associated with LMZ [1.24 (1.08, 1.45)]. However, MPO was associated with a lower risk of high transferrin receptor [0.86 (0.74, 0.98)], NEO with a lower risk of low retinol [0.75 (0.62, 0.89)], and AAT with a lower risk of low plasma zinc [0.83 (0.70, 0.99)]. Greater nutrient intake densities (vitamins A and B6, calcium, protein, and zinc) were negatively associated with EED. Inverse associations between nutrient densities and micronutrient deficiency largely disappeared after adjustment for EED, suggesting that EED mediates these associations. Conclusions EED is independently associated with an increased risk of low ferritin, low retinol, and anemia. Greater nutrient density from complementary foods may reduce EED, and the control of micronutrient deficiencies may require control of EED.

Objective: To investigate the in¯uences of size at birth, breastfeeding and morbidity on growth during infancy in poor areas of urban Bangladesh. Design: This was a prospective observational study of a cohort of newborn infants followed until 12 months of age. Setting: Slum areas of Dhaka City in Bangladesh. Subjects: A total of 1654 newborn infants were enrolled at birth, and follow-up was completed for 1207 infants. Repeated anthropometric measurements and interviews of caretakers on infant feeding and morbidity were conducted. A mixed effects regression method was used for modeling infant growth. Results: After adjusting for other variables, mean differences in body weight by birth weight and length, smallfor-gestational age and prematurity categories remained relatively constant throughout infancy. A positive impact of exclusive breastfeeding in the ®rst 3 ± 5 months on infant growth was detectable at 12 months of age. Although the bigger babies in the sample tended to grow relatively even bigger; exclusive breastfeeding appeared to counteract this pattern. Reported diarrhoea was associated with lower body weights and lengths even after adjusting for feeding patterns.Conclusions: Size at birth has an important role in determining growth during infancy. Effective strategies for improving birth weight, poorly addressed till now in Bangladesh, are needed. The sustained effect on growth and the even more bene®cial effect in lighter infants are compelling reasons for promotion of exclusive breastfeeding in early infancy.