Peer-reviewed article
Infection, nutritional status, and body composition: Associations at birth and 6 months postnatally in Soweto, South Africa
Douglas J. Momberg, Rachel Bell, Shane Anthony Norris, Christian Bwangandu Ngandu, Linda Richter et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined how infections in the first 6 months of life affect infant body composition and nutritional status in Soweto, South Africa. Researchers tracked 156 healthy infants from birth to 6 months, measuring infections and morbidity symptoms alongside their growth and body composition. Infants who experienced more infections had lower fat mass but higher muscle mass, while those with access to safe sanitation had better height-for-age scores.
Key points
- Cumulative morbidity from birth to 6 months was associated with lower fat mass index and fat mass, but higher fat-free mass
- No significant associations were found between morbidity and height-for-age or weight-for-height measurements
- Access to safely managed sanitation facilities was associated with higher height-for-age scores
- Higher birthweight was associated with better nutritional and body composition outcomes across multiple indicators
- The study suggests that immune responses to infection may alter body composition during this critical period of infant development
Limitations
The study is observational and cannot establish causality between infection and body composition changes. The findings are specific to one urban population in South Africa and may not generalise to other contexts.
Abstract
INTRODUCTION: The impact of infection on infant nutritional status, body size, and growth is well documented. However, research into the impact of infection on infant body composition is limited. Greater understanding is, therefore, needed on the effects of infection in early life. METHODS: Associations between a composite morbidity index consisting of the sum of the cumulative tallies for a range of symptoms representing infection and morbidity in the infants and nutritional status (height-for-age (HAZ), and weight-for-height (WHZ)), and body composition (fat-free mass (FFM), fat mass (FM), fat-free mass index (FFMI), and fat mass index (FMI)) at 6 months of age were investigated using hierarchical regression analysis. RESULTS: The sample comprised data between birth and 6 months postnatally, of 156 infants who were a priori born healthy in Soweto, South Africa. Morbidity, over the cumulative period of birth to 6 months, was associated with lower FMI (β = -1.77) and lower FM (β = -0.61), and conversely with higher FFM (β = 0.94), in infants at 6 months. No associations were found between the morbidity index and FFMI, HAZ, and WHZ. Increased birthweight was associated with a higher FFM (β = 0.66), HAZ (β = 1.14), and WHZ (β = 0.87). Finally, safely managed sanitation facilities, representative of reduced environmental exposure to fecal-oral transmission pathways were associated with a higher HAZ (β = 1.21). DISCUSSION: Reduction in FMI and FM and exposure to inflammatory cytokines associated with mounting an immune response could alter phenotypic trajectories during to this period of plasticity. From a public health perspective, these results imply that it is important to intensify efforts to prevent infection in infants in the first 6 months postnatally, and that these efforts should concentrate on access to safely managed sanitation facilities.