Timing of the infancy-childhood growth transition in rural Gambia

Bernstein Rm,Sosseh F,Affara N,Vance Ea,Ong Kk,Dunger Db,Drammeh S,Moore Se,OConnor Gk,Prentice Am,Faal A

doi:10.1530/ey.17.13.10

Abstract

A delayed transition from the infancy to the childhood growth stage contributes to sub-optimal growth outcomes. Using a novel method to assess the timing of infancy-childhood transition (quantification of patterns of adjacent monthly weight-for-age z-score (WAZ) deviation correlations), this transition was found to take place at the age of 12 months in UK. The authors in this study find that the transition takes place earlier in rural Gambia (9 months). The authors hypothesize that while a later transition allows maximal extension of the high rates of growth during the infancy, an earlier transition may negatively affect the growth outcomes in childhood but also offers an extended window for later catch-up.

Highlights

The human growth trajectory is complex compared to other large-bodied mammals; passing through infancy, childhood, juvenility, and adolescence before reaching adulthood [1] it is relatively prolonged via the extension of the pre-pubertal period [2], and is best described as sinuous and containing periods of both relatively slow growth and accelerated growth
Cole et al [28] identified two ‘phases’ of deviation correlations within the first year of infant life: [1] positive feedback during the first few months, and [2] negative feedback from 6 to 10/11 months. These feedback phases were proposed as the mechanism by which an individual finds and tracks their growth canal
Cole et al [28], and [2] the ICT in Gambian infants born in the wet season would be delayed (DICT) relative to the ICT in infants born in the dry season

Summary

Introduction

The human growth trajectory is complex compared to other large-bodied mammals; passing through infancy, childhood, juvenility, and adolescence before reaching adulthood [1] it is relatively prolonged via the extension of the pre-pubertal period [2], and is best described as sinuous and containing periods of both relatively slow growth and accelerated growth. Earlier perspectives held that certain stages of growth are uniquely derived in humans (e.g., childhood), and the insertion of these stages into an ancestral primate growth trajectory are responsible for the prolongation of growth overall in humans—itself hypothesized to permit a longer period of brain development [3], to build metabolic and cognitive capital to use in later life [4], or to increase chances of success in relationship to extrinsic mortality risk both in adulthood and during immaturity [5, 6]. More recent analyses have suggested that while the human growth trajectory is extended relative to that of our closest living relatives, those stages previously considered novel are present in other non-human primate species, and relatively accelerated, and/or compressed in their time course of expression [7,8,9,10,11,12]. Growth in early life has been linked to developmental and health outcomes across the life course such as childhood obesity [18]; childhood adiposity; and age at menarche [19]

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Conclusion