Enriching our understanding of the effects of childhood poverty: lessons from Bangladesh.

A sobering fact to consider: the likelihood that any of us will achieve a state of sustained well-being as adults is bounded quite early in life by factors entirely beyond our control. Where one is born, when, and to whom establishes guardrails for a path of development to which merit or effort contributes but modestly. Of all the disadvantageous contingencies to which one might be exposed in early life, poverty is among the most punishing. Its effects are known to be pervasive, long lasting, and protean in their manifestations. Those who start out life poor grow less well, are subject to more frequent and grave episodes of illness, attain lesser levels of academic advancement, experience cognitive challenges unlike their more fortunate counterparts, earn less money, acquire fewer assets, develop adult-onset chronic illnesses at higher rates, marry less often, and die earlier. Despite voluminous documentation of these associations, there is yet much that remains to be explained about the pathways through which poverty exerts these pernicious influences and, in particular, its impact on cognitive development. In this issue of Pediatrics, Hamadani and colleagues contribute to our understanding of this dynamic through their study of a cohort of children in rural Bangladesh. The authors enrolled 2853 singleton children born between May 2002 and December 2003 and collected data on their parents, their growth parameters over the succeeding 64 months, the material resources available to their families, and information about the richness of the environments in which they were raised. They then linked these factors longitudinally to objective measures of the children’s cognitive function. The authors divided the cohort into wealth quintiles and compared the cognitive outcomes of the children at 7, 18, and 64 months of age. They found differences in cognitive ability between children from the poorest compared with the richest quintile as early as 7 months, and they documented that those differences increased over time. Once parental education, growth, and the home environment were taken into account in their multivariate analytic framework the effect of poverty was dramatically reduced suggesting that these 3 elements constitute important mediating pathways through which wealth affects cognitive ability over time. The study design these authors used has much to recommend it. It is a longitudinal cohort study that collected data on children’s parentage and environment from the outset rather than depending on recall, as is the case in many cross-sectional studies performed to date. The authors took great pains to amass data from objective measures including the age-appropriate developmental screening instruments that had been translated and adapted for use in this rural community. They used wealth rather than simply income to estimate a broad range of material resources available to families. Multivariate logistic regressions helped isolate the impact of specific features of the child’s AUTHOR: Andrew D. Racine, MD, PhD