Growth trajectories and early-life attention and memory outcomes: parallel analyses of cohorts in Malawi and the United States.

BACKGROUND

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

OBJECTIVES

We aimed to identify growth trajectories and explore 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, United States (n = 101) at birth and at 6-9, 8-12, and 11-15 mo. 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 United States), associations between growth trajectories and cognitive outcomes were assessed with eye tracking between 6 and 15 mo. The Infant Orienting With Attention task measured attention (reaction time, task error); the 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 World Health Organization (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 mo; differences ranged from 69.84 [95% confidence interval (CI): 21.49, 118.19] to 86.57 ms (95% CI: 25.32, 147.82). Boys with low-linear trajectories showed faster reaction times [-25.72 (95% CI: -48.99, -2.46) to -54.69 ms (95% CI: -90.36, -19.02)] but lower shift rate [-0.06 shifts/s (95% CI: -0.12, 0.00)]. In the United States, boys with high-weight trajectory had slower reaction times by 24.85 ms (95% CI: 1.29, 48.41) at 11-12 mo. At 12-15 mo, boys with high-weight trajectory in Malawi demonstrated poorer novelty preference [-0.14 on a 0-1 scale (95% CI: -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. This trial was registered at clinicaltrials.org as NCT03385252 (Mazira study; https://clinicaltrials.gov/study/NCT03385252) and NCT03229863 (IMiND study; https://clinicaltrials.gov/study/NCT03229863).