Growth trajectories and early-life attention and memory outcomes: Parallel analyses of cohorts in Malawi and the USA.

Background

Variations in early-life growth patterns may reflect differences in early postnatal exposures influencing child attention and memory.

Objective

We identified growth trajectories and explored their associations with attention and memory among infants and young children across time points.

Methods

Anthropometric data were collected from cohorts in Malawi (n=600) and suburban California, USA (n=101) at birth and at 6-9, 8-12, and 11-15 months. Latent class trajectory modeling identified sex-specific growth pattern classes for weight and weight-for-age z-score in both cohorts, and for length, length-for-age, and weight-for-length z-scores in Malawi. In a subgroup (n=458 in Malawi; n=92 in the USA), associations between growth trajectories and cognitive outcomes were assessed with eye-tracking between 6-15 months. The Infant Orienting with Attention task measured attention (reaction time, task error); Visual Paired Comparison task measured memory (novelty preference, peak look duration, shift rate; only in Malawi). Mixed effects models evaluated associations, adjusting for child, parental, and household characteristics, with trajectories closest to WHO standards used as reference groups.

Results

Growth trajectories varied by cohort, aligning with WHO standards and others showing acceleration or deceleration. In Malawi, girls with lowest-linear trajectories had slower reaction times at 6-9 months; differences ranging from 69.84 (95% CI: 21.49, 118.19) to 86.57 ms (25.32, 147.82). Boys with low-linear trajectories showed faster reaction times [-25.72 (-48.99, -2.46) to -54.69 ms (-90.36, -19.02)] but lower shift rate (-0.06 shifts/s; -0.12, 0.00). In the USA, boys with high-weight trajectory had slower reaction times by 24.85 ms (1.29, 48.41) at 11-12 months. At 12-15 months, boys with high-weight trajectory in Malawi demonstrated poorer novelty preference (-0.14 on a 0-1 scale; -0.24, -0.04).

Conclusions

Exploratory findings suggest that early growth patterns are linked to attention and memory especially among boys, highlighting the importance of longitudinal sex-specific evaluation. CLINICAL TRIAL REGISTRY NUMBER NCT03385252 (Mazira study; https://clinicaltrials.gov/study/NCT03385252), NCT03229863 (IMiND study; https://clinicaltrials.gov/study/NCT03229863).