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

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 similar to 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 R-2 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 R-2 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 (<15(th) 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.