Trajectories and social determinants of child cognitive development: a prospective cohort study from infancy through middle childhood in Dhaka, Bangladesh.

BACKGROUND

Over a third of children globally do not meet their developmental potential, and children living in low and middle-income countries (LMICs) are most vulnerable. Understanding the contextual factors that influence cognitive development for children in LMICs is crucial to inform and develop interventions. We sought to characterize developmental trajectories of cognition in Bangladeshi children and identify salient social determinants.

METHODS

We used a longitudinal design and included 542 children living in Dhaka, Bangladesh. Social determinants (maternal and paternal education, housing risks, household assets, and food security) were assessed at baseline visits using a combination of oral interviews and home assessments. Cognitive development was assessed at 6 months, 2, 3, 4, 5, and 7 years. A total of 1397 cognitive assessments were completed across all participants. Growth curve models and mixed effect models were used.

FINDINGS

In children living above the poverty line, there was increasing deviation from expected cognitive scores from 6 months to 2 years (-12.85,  < 0.001) with stable scores from 2 to 7 years. For those below the poverty line, there were widening disparities from expectations in scores from 6 months to 4 years (-24.58,  < 0.001) with stable scores from 4 to 7 years. Higher levels of maternal education ( = 2.22,  = 0.03) and more food security ( = 4.48,  < 0.001) were protective for cognition longitudinally. Interaction effects between poverty level and maternal education and food security respectively were observed.

INTERPRETATION

Cognitive development trajectories showed increasing disparities from expectations in the first two years of life, with more pronounced and lasting effects through 4 years for children below the poverty line. Maternal education and food security had promotive/protective effects on longitudinal cognitive development scores for the full sample. Maternal education and food security had stronger effects on cognitive development for children living below the poverty line compared to those living above the poverty line.

FUNDING

Funding for the study was provided by a grant from the Bill and Melinda Gates Foundation (OPP1111625) to CAN.