Critical windows for nutritional interventions against stunting

Abstract

An analysis of early growth patterns in children from 54 resource-poor countries in Africa and Southeast Asia shows a rapid falloff in the height-for-age z score during the first 2 y of life and no recovery until ≥5 y of age. This finding has focused attention on the period -9 to 24 mo as a window of opportunity for interventions against stunting and has garnered considerable political backing for investment targeted at the first 1000 d. These important initiatives should not be undermined, but the objective of this study was to counteract the growing impression that interventions outside of this period cannot be effective. We illustrate our arguments using longitudinal data from the Consortium of Health Oriented Research in Transitioning collaboration (Brazil, Guatemala, India, Philippines, and South Africa) and our own cross-sectional and longitudinal growth data from rural Gambia. We show that substantial height catch-up occurs between 24 mo and midchildhood and again between midchildhood and adulthood, even in the absence of any interventions. Longitudinal growth data from rural Gambia also illustrate that an extended pubertal growth phase allows very considerable height recovery, especially in girls during adolescence. In light of the critical importance of maternal stature to her children's health, our arguments are a reminder of the importance of the more comprehensive UNICEF/Sub-Committee on Nutrition Through the Life-Cycle approach. In particular, we argue that adolescence represents an additional window of opportunity during which substantial life cycle and intergenerational effects can be accrued. The regulation of such growth is complex and may be affected by nutritional interventions imposed many years previously.

FIGURE 1.

Mean anthropometric z scores for 54 studies from low- and middle-income countries relative to the WHO standard. Reproduced with permission from reference .

FIGURE 2.

Changes in HAZs between 24 and 48 mo in 30 African countries. Calculated from data provided in Table 4 of reference . HAZ, height z score.

FIGURE 3.

Differential timing of the growth of body systems in humans.

FIGURE 4.

Mean height-for-age z scores and changes in height-for-age z scores for participants in the Consortium of Health Oriented Research in Transitioning Societies studies, divided by tertiles of adult height. Reproduced with permission from reference .

FIGURE 5.

LOWESS-fitted curves applied to semilongitudinal data on growth collected between 1951 and 2006 in rural Gambia (n = 36,828 data points). Height-for-age z scores were calculated against the UK 1990 reference (11). Panel A = males, panel B = females. Curves drawn for data collected before and after 1970 illustrate the robustness of the growth patterns. The slightly higher lines in adulthood are the post-1970 data.

FIGURE 6.

Changes in height relative to the UK 1990 reference (11) in cohorts of 80 boys and 80 girls (17, 18) measured longitudinally in rural Gambia. Loss-to-follow up rates were low, as indicated at the base of the figure. Ht, height; SDS, SD score.