A Novel method for the identification and quantification of weight faltering.

Daniel J Naumenko,James Dykes,Andrew M Prentice,David B Dunger,Ken K Ong,Nabeel Affara,Saikou Drammeh,Robin M Bernstein,Fatou Sosseh,Sophie E Moore,Abdoulie Faal,Zofia Stanley,G Kesler O'Connor,Andrew M Doel

doi:10.1002/ajpa.24217

Abstract

ObjectiveWe describe a new method for identifying and quantifying the magnitude and rate of short‐term weight faltering episodes, and assess how (a) these episodes relate to broader growth outcomes, and (b) different data collection intervals influence the quantification of weight faltering.Materials and methodsWe apply this method to longitudinal growth data collected every other day across the first year of life in Gambian infants (n = 124, males = 65, females = 59). Weight faltering episodes are identified from velocity peaks and troughs. Rate of weight loss and regain, maximum weight loss, and duration of each episode were calculated. We systematically reduced our dataset to mimic various potential measurement intervals, to assess how these intervals affect the ability to derive information about short‐term weight faltering episodes. We fit linear models to test whether metrics associated with growth faltering were associated with growth outcomes at 1 year, and generalized additive mixed models to determine whether different collection intervals influence episode identification and metrics.ResultsThree hundred weight faltering episodes from 119 individuals were identified. The number and magnitude of episodes negatively impacted growth outcomes at 1 year. As data collection interval increases, weight faltering episodes are missed and the duration of episodes is overestimated, resulting in the rate of weight loss and regain being underestimated.ConclusionsThis method identifies and quantifies short‐term weight faltering episodes, that are in turn negatively associated with growth outcomes. This approach offers a tool for investigators interested in understanding how short‐term weight faltering relates to longer‐term outcomes.

Highlights

Determining whether an individual's growth is due to natural/normal variation or is indicative of adverse conditions, and pinpointing when growth perturbations begin (Victora et al, 2010), are areas of continued research and debate
It is standard and near-universal practice among health care workers to monitor growth during infancy and childhood to pick up on potential disturbances to a child's growth trajectory as potential indicators of challenges to health. Growth standards, such as World Health Organization (WHO)-guided thresholds for wasting and stunting are internationally accepted. While metrics such as wasting and stunting may indicate when an individual is not growing normally relative to a reference population, they dichotomize the inherently continuous process of growth faltering and have only been able to resolve the initiation of the state of growth faltering as happening in utero or the first 1000 days of life (Christian et al, 2013; de Onis et al, 2013; Dewey & Huffman, 2009)
WHO Growth Reference (WHO Multicentre Growth Reference Study Group, 2006) cutoffs indicate small size or stature relative to the reference, with a height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WFH) < −2 SD as the standard cutoff, as noted above (Alderman & Headey, 2018). These cutoffs are often used to indicate faltering in a given anthropometric dimension at a given age, they are limited in utility as an individual who falls at or below these cutoffs may have started out small, meaning they are tracking their appropriate trajectory