Associations between Micronutrient Status and Post-Hospital Discharge Growth among 2–23-Month-Old Children with Acute Illnesses in Africa and South-Asia

Abstract

Introduction: The high prevalence of wasting among children under five in low- and middle-income countries remains a significant public health concern, contributing to elevated morbidity and mortality rates. Recent studies have highlighted that even after hospital discharge, these children continue to face an increased incidence of mortality and nutritional factors may contribute to this elevated risk. Malnutrition has been shown to exert detrimental effects on innate and adaptive immune functions, increasing children's susceptibility to infections. At the same time, diseases can deplete vital micro and macronutrients, resulting in impaired growth, which, in turn, is associated with elevated mortality risk. This study aimed to investigate associations between serum micronutrient levels and changes in growth among children aged 2–23 months following hospital discharge for acute illnesses. Method: This secondary data analysis utilized CHAIN nested case-cohort data. Children aged 2-23 months with acute illnesses who had been admitted to hospitals and discharged as survived across six different countries were included. The associations between micronutrient status at hospital discharge and day 45 follow-up growth outcomes, measured as changes in mid-upper arm circumference Z-score (ΔMUACZ), weight-for-height Z-score (ΔWHZ), length-for-age Z-score (ΔLAZ), and weight-for-age Z-score (ΔWAZ) were examined. Initial univariate regression analyses were conducted to examine the associations between individual micronutrients and early post-discharge growth. Subsequently, multivariate analysis using linear regression was employed to confirm associations between selected micronutrients and growth based on the univariate results and adjusting for potential confounders. Results: Univariate analysis found significant associations between several micronutrients and growth outcomes. High calcium and copper levels were negatively associated with early post-discharge growth, as reflected by changes in ΔMUACZ, ΔWHZ and ΔWAZ scores. Conversely, serum retinol, magnesium, potassium, calcium, B1, B2, B5, B7 and vitamin E each showed positive associations with at least one measure of growth. However, in multivariate analysis, only vitamin B2 maintained a significant association with increased changes in ΔMUACZ and ΔWAZ scores. Conclusion: Micronutrients, including copper, calcium, B vitamins, vitamin A, and vitamin E, demonstrated modest associations with early post-discharge growth. However, these associations were attenuated by adjustment for confounders such as preterm birth, suboptimal breastfeeding practices, stunting, diarrhea, pneumonia, and systemic inflammation. Deficiencies in the aforementioned micronutrients may be negatively associated with early post-discharge growth through various physiological mechanisms. However, micronutrient deficiencies alone are not strong independent determinants of early post-discharge growth. While micronutrient supplementation remains an important intervention regardless of its effect on post-discharge growth, promoting early post-discharge growth through micronutrient supplementation alone is unlikely to be effective without addressing underlying factors, such as preterm birth, feeding practices and infectious morbidities.