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).