Stunting Mediates the Association between Small-for-Gestational-Age and Postneonatal Mortality

Abstract

Background: In sub-Saharan Africa, one-third of all births are small for gestational age (SGA), and 4.4 million children are stunted; both conditions increase the risk of child mortality. SGA has also been shown to increase the risk of stunting.Objective: We tested whether the association between SGA and postneonatal mortality is mediated by stunting.Methods: We used longitudinal data from children aged 6 wk to 24 mo (n = 12,155) enrolled in the ZVITAMBO (Zimbabwe Vitamin A for Mothers and Babies) trial. HIV exposure was defined based on maternal HIV status at baseline. SGA was defined as birthweight <10th percentile of the INTERGROWTH-21st (International Fetal and Newborn Growth Consortium for the 21st Century) standards. We used a standard mediation approach by comparing the attenuation of the risk when the mediator was added to the model. We used Cox proportional hazards models first to regress SGA on postneonatal mortality, controlling for age. Stunting (length-for-age z score <−2) was then included in the model to test mediation.Results: Approximately 20% of children were term SGA, and 23% were stunted before their last follow-up visit. In this cohort, 31% of children were exposed to HIV; the HIV-exposed group represented a pooled group of HIV-infected and HIV-exposed but uninfected children. Postneonatal mortality was significantly higher among children born SGA (HR: 1.5; 95% CI: 1.3, 1.7). This association was attenuated and not statistically significant when stunting was included in the model, suggesting a mediation effect (HR: 1.1; 95% CI: 0.91, 1.3). When stratified by HIV exposure status, we observed a significant attenuation of the risk, suggesting mediation, only among HIV-exposed children (model 1, HR: 1.3; 95% CI: 1.1, 1.6; model 2, HR: 1.1; 95% CI: 0.88, 1.3).Conclusions: This analysis aids in investigating pathways that underlie an observed SGA-mortality relation and may inform survival interventions in undernourished settings.

Undernutrition of HEU infants in their first 1000 days of life: A case in the urban-low resource setting of Mukuru Slum, Nairobi, Kenya

“…Moreover, the study noted that although the birth weight of the HUU infants correlated with their WFLZ (P = 0.02), WFAZ (P = 0.008), and BAZ (P = 0.017), this was not the case among the HEU infants. Although a previous study (Oddo et al., 2016) linked small for gestational age with stunting among the HEU infants, this study did not find any relationship because the number of infants who had low birth weights in the study was only 20%.…”

Vision of Research on Human Linear Growth

“…Indeed, in an application of the INTER-GROWTH standards in Zimbabwe, an initial association between fetal growth status and mortality disappeared when adjustments were made for length (stunting). 51 In utero length trajectories would be a useful subject of study, but weight and volume indices are unlikely to be adequate proxies for fetal linear growth, and the current crown-rump dimension excludes the critical variance in the lower extremities.…”

Prevalence, feeding practices, and factors associated with undernutrition among HIV-exposed uninfected children aged 6 to 18 months in Bushenyi district, western Uganda: A cross-sectional study

“…Children with a history of low birth weight were more vulnerable to undernutrition. Previous studies linked small for gestational age with undernutrition among the HIV-exposed uninfected children [14], [41]. However, Nduta & Marnane did not nd any relationship between history of low birth weight and undernutrition [42].…”