Abstract:
It is important to identify the periods during childhood when exposure to environmental
risk factors results in long‐term neurodevelopmental deficits. Stunting and
anaemia may be sensitive indicators of exposure to such risks. In a prospective cohort
enrolled before birth, we investigated the association of developmental scores at 4–
6 years with (a) birth length and linear growth during three postnatal periods and (2)
haemoglobin (Hb) concentration at three time points. Children were participants in a
follow‐up study of a randomized controlled trial of nutritional supplementation in
Ghana. At 4–6 years, cognitive, motor, and social–emotional developments were
assessed using standard tests adapted for this population. We estimated the associations
of length‐for‐age z‐score (LAZ) at birth and postnatal linear growth (n = 710) and
Hb (n = 617) with developmental scores in regression models, using multistage least
squares analysis to calculate uncorrelated residuals for postnatal growth. Cognitive
development at 4–6 years was significantly associated with LAZ at birth (β = 0.12,
95% CI = 0.05, 0.19), ΔLAZ from 6 to 18 months (β = 0.16, 95% CI = 0.04, 0.28),
and Hb at 18 months (β = 0.13, 95% CI = 0.06, 0.20), but not with ΔLAZ during 0–
6 months, ΔLAZ from 18 months to 4–6 years, Hb at 6 months, or Hb at 4–
6 years. No evidence of associations with motor or social–emotional development
were found. These results suggest that in similar contexts, the earlier periods prior
to birth and up to 18 months are more sensitive to risk factors for long‐term cognitive
development associated with LAZ and Hb compared with later childhood. This may
inform the optimal timing of interventions targeting improved cognitive development.
