Effect of micronutrient supplementation on diarrhoeal disease among stunted children in rural South Africa.

BACKGROUND/

OBJECTIVE

The efficacy of zinc combined with vitamin A or multiple micronutrients in preventing diarrhoea is unclear in African countries with high prevalence of human immunodeficiency virus (HIV)-exposed children. Potential modifying factors, such as stunting, need to be addressed. The objective of this study was to determine whether adding zinc or zinc plus multiple micronutrients to vitamin A reduces diarrhoea incidence, and whether this differs between the strata of stunted or HIV-infected children.

METHODS

We analyzed data from a randomized, controlled, double-blinded trial (ClinicalTrials.gov NCT00156832) of prophylactic micronutrient supplementation to children aged 6-24 months. Three cohorts of children: 32 HIV-infected children, 154 HIV-uninfected children born to HIV-infected mothers and 187 uninfected children born to HIV-uninfected mothers, received vitamin A, vitamin A plus zinc or multiple micronutrients, which included vitamin A and zinc. The main outcome was incidence of diarrhoea. Poisson regression was used in intent-to-treat analyses. Stratified analyses followed testing for statistical interaction between intervention and stunting.

RESULTS

We observed no significant differences in overall diarrhoea incidence among treatment arms. Stunting modified this effect with stunted HIV-uninfected children having significantly lower diarrhoea incidence when supplemented with zinc or multiple micronutrients compared with vitamin A alone (2.04 and 2.23 vs 3.92 episodes/year, respectively, P=0.024). No meaningful subgroup analyses could be done in the cohort of HIV-infected children.

CONCLUSIONS

Compared with vitamin A alone, supplementation with zinc and with zinc and multiple micronutrients, reduced diarrhoea morbidity in stunted rural South African children. Efficacy of zinc supplementation in HIV-infected children needs confirmation in studies that represent the spectrum of disease severity and age groups.