The MAL-ED Cohort Study: Methods and Lessons Learned When Assessing Early Child Development and Caregiving Mediators in Infants and Young Children in 8 Low- and Middle-Income Countries

Abstract

More epidemiological data are needed on risk and protective factors for child development. In The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study, we assessed child development in a harmonious manner across 8 sites in Bangladesh, Brazil, India, Nepal, Pakistan, Peru, South Africa, and Tanzania. From birth to 24 months, development and language acquisition were assessed via the Bayley Scales of Infant and Toddler Development and a modified MacArthur Communicative Development Inventory. Other measures were infant temperament, the child's environment, maternal psychological adjustment, and maternal reasoning abilities. We developed standard operating procedures and used multiple techniques to ensure appropriate adaptation and quality assurance across the sites. Test adaptation required significant time and human resources but is essential for data quality; funders should support this step in future studies. At the end of this study, we will have a portfolio of culturally adapted instruments for child development studies with examination of psychometric properties of each tool used.

Adaptation of the Mullen Scales of Early Learning for use among infants aged 5‐ to 24‐months in rural Gambia

“…Within the first 24-months of life, neuronal networks develop most rapidly and exhibit high plasticity (Fox, Calkins, & Bell, 1994;Fox, Levitt, & Nelson, 2010;Kolb & Gibb, 2011). Environmental factors in early life, such as home environment, caregiver responsiveness, infection and diet, have important and lasting impacts on neural development (e.g., Murray- Kolb et al, 2014). Consequently, the infant brain is highly vulnerable to compromised development during this time.…”

Tropical and travel-associated norovirus

“…Human studies are currently being conducted by the Interactions of Malnutrition & Enteric Infections: Consequences for Child Health and Development (MAL-ED) group, but results are pending [38■■,39■–41■,42–49]. Particularly relevant to assessing tropical norovirus infections are investigations that assess the role of the gut microbiota in nutritional status [50■], immune markers and vaccine failure in undernourished populations [51■,52■], tropical enteropathy and gut function [51■,53■■,54], and the long-term impact of these factors on child development [38■■,55]. …”

Early-life enteric infections: relation between chronic systemic inflammation and poor cognition in children

“…[4][5][6] Prolonged or repeated enteric infections have long-lasting consequences, since the effects may extend throughout a lifetime and may even be multigenerational, leading to an unresolved vicious cycle of poverty, low education, and costly poor health and well-being of individuals and society. 7 Although chronic low-grade intestinal inflammation has been increasingly recognized as a factor contributing to poor intestinal absorption of nutrients, 8 the underlying mechanisms remain poorly understood.…”