Monthly measurement of child lengths between 6 and 27 months of age in Burkina Faso reveals both chronic and episodic growth faltering

Abstract

Background: Linear growth faltering is determined primarily by attained heights in infancy, but available data consist mainly of cross-sectional heights at each age.

Objectives: This study used longitudinal data to test whether faltering occurs episodically in a few months of very low growth, which could potentially be prevented by timely intervention, or is a chronic condition with slower growth in every month of infancy and early childhood.

Methods: Using anthropometric data collected monthly between August 2014 and December 2016, we investigated individual growth curves of 5039 children ages 6-27 mo in Burkina Faso (108,580 observations). We evaluated growth-curve smoothness by level of attained length at ∼27 mo by analyzing variation in changes in monthly growth rates and using 2-stage regressions: 1) regressing each child's length on their age and extracting R2 to represent curve smoothness, initial length, and average velocity by age; and 2) regressing extracted parameters on individual-level attained length.

Results: Short children started smaller and remained on their initial trajectories, continuously growing slower than taller children. Growth between 9 and 11 mo was the most influential on attained length; for each 1-cm/mo increase in growth velocity during this period, attained length increased by 6.71 cm (95% CI: 6.59, 6.83 cm). Furthermore, a 0.01 increase in R2 from individual regression of length on age was associated with a 3.10-cm higher attained length (95% CI: 2.80, 3.41 cm), and having 2 consecutive months of slow growth (<15th centile relative to the sample) was associated with 1.7-cm lower attained length (95% CI: -1.80, -1.59 cm), with larger effects in younger children, suggesting that smoother growth patterns were also associated with higher attained length.

Conclusions: Children who experience extreme growth faltering are likely less resilient to systematic growth-limiting conditions as well as episodic insults to their growth.This trial was registered at clinicaltrials.gov as NCT02071563.

Keywords: anthropometry; child growth; linear growth; nutrition; undernutrition.

© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.

Figures

FIGURE 1

Kernel-density plots of LAZs at ages 6 mo (n = 3809), 12 mo (n = 4760), 18 mo (n = 4776), and 24 mo (n = 4807), by quintile of attained length at study end (∼27 mo). The dashed vertical line is the WHO reference population of healthy children whose z scores have a mean of 0 and an SD of 1, centered at 0 on the dashed vertical line; the solid vertical line is the stunting cutoff (−2 SD < WHO mean). LAZ, length-for-age z score; Q, quintile.

FIGURE 2

Length (A) and length velocity (B) by age among children from selected centiles of attained length. Each colored line represents the growth curve over time of 1 individual child. Horizontal bars indicate (A) mean attained length and (B) mean length velocity . The graphs use the sensitivity analysis data set containing only full cases with no imputations. n = 12–13 in each centile.

FIGURE 3

LAZs (A) and LADs (B) by age among children from selected centiles of attained length. Each colored line represents the growth curve over time of 1 individual child. Horizontal bars indicate (A) the reference population z score mean and (B) 0 LAD from the reference population median. The graphs use the sensitivity analysis data set containing only full cases with no imputations. n = 12–13 in each centile. LAD, length-for-age difference; LAZ, length-for-age z score.