Interventions that target linear growth in childhood such as those aimed at combating malnutrition may not provide concurrent benefits in neurodevelopment, according to study data published in Lancet Global Health. Instead, interventions that promote caregiving improved neurobehavioral development most effectively in childhood.
Investigators conducted a systematic review of MEDLINE, CINAHL, and PsychINFO from inception through June 25, 2019, for randomized trials conducted during pregnancy or in children aged 0 to 5 years. Eligible trials reported the effects of any intervention on any of the following outcomes: length-for-age Z-score (LAZ); height-for-age Z score (HAZ); and neurodevelopment, including motor, cognitive or mental, language, and social-emotional or behavioral development. Effect sizes of each intervention on LAZ, HAZ, and neurodevelopment were calculated. Meta-regression coefficients were generated for the association between intervention effects on LAZ or HAZ and intervention effects on neurodevelopmental outcomes. Pooled effect sizes for different types of interventions were also assessed.
A total of 7207 studies were identified in the search, from which 75 publications were selected for analysis. Together, these 75 studies investigated the effects of 122 interventions in 72,275 children. The major intervention categories were nutritional supplementation (51 studies) and caregiving (14 studies). For all interventions, effect sizes on LAZ or HAZ were significantly associated with effect sizes on social-emotional development score (β, 0.23; 95% CI, 0.05-0.41; P =.02), but not on cognitive, language, or motor development scores (all P >.05). For nutritional interventions, effect sizes on LAZ or HAZ were significantly associated with effect sizes on cognitive (β, 0.40; 95% CI, 0.04-0.77; P =.049) and motor (β, 0.43; 95% CI, 0.11-0.75; P =.01) scores. Across all nutritional supplementation studies, significant positive pooled effect sizes were observed for each outcome: LAZ or HAZ (effect size (ES), 0.05; 95% CI, 0.01-0.09; P =.01); cognitive or mental score (ES, 0.06, 95% CI, 0.03-0.10; P <.01); language score (ES, 0.08; 95% CI, 0.03-0.13; P =.01), motor score (ES, 0.08; 95% CI, 0.04-0.12; P <.01); and social-emotional score (ES, 0.08; 95% CI, 0.02-0.12; P =.01). Notably, these positive pooled effect sizes only persisted in low- and middle-income study settings; in nutritional studies conducted in high-income settings, LAZ, HAZ, and neurodevelopmental outcomes were not significantly correlated with nutritional supplementation. Notably, the pooled effect sizes of caregiving interventions on cognitive, language, and motor scores were significantly larger (range, 0.38-0.48) than the effects of nutritional supplementation (range, 0.05-0.08). However, caregiving interventions did not have a significant effect on LAZ or HAZ (-0.01; 95% CI, -0.07 to 0.05; P =.74).
These data suggest that childhood interventions that target responsive care and learning opportunities are most effective in promoting cognitive, language, and motor development. Linear growth and neurodevelopment, while associated, did not share the same set of determinants. Investigators thus promote interventions that specifically target neurologic and behavioral development in children, in tandem with supplementation for linear growth.
Prado EL, Larson LM, Cox K, Bettencourt K, Kubes JN, Shankar AH. Do effects of early life interventions on linear growth correspond to effects on neurobehavioural development? A systematic review and meta-analysis. Lancet Glob Health. 2019;7(10):e1398-e1413.