Background: Studies on the effect of vitamin A supplementation on growth have yielded various results. It is possible that such growth is dependent on the burden of infectious diseases in the population.
Methods: We analysed data from a randomized, double-masked, placebo-controled trial to examine the role of respiratory infections and diarrhoea in modifying the growth response to vitamin A supplementation. A single high dose of vitamin A or placebo was given every 4 months to 1405 children aged 6-48 months, and 4430 child treatment cycles were used in this analysis.
Results: Vitamin A supplementation modestly improved linear but not ponderal growth of children who experienced little respiratory infection and especially of those who had vitamin A intake below the normative requirement (<400 RE/day). Children who received vitamin A and were free of respiratory infection grew 0.22 cm/4 months (95% CI: 0.08, 0.37) more in height than the placebo group, but those with > or =21.5% of days of respiratory infection did not show a significant growth response to vitamin A supplementation. Children who experienced no respiratory infection and had vitamin A intake <400 RE/day benefited most, gaining 0.31 cm/4 months (95% CI: 0.10, 0.52) more in height compared to the placebo group. Diarrhoea was associated with poorer growth, but did not significantly modify the effect of vitamin A supplementation on growth.
Conclusions: Vitamin A supplementation improves the linear growth of children who have a low intake of vitamin A but this impact is muted with increasing levels of respiratory infections.
PIP: This randomized, double-masked, placebo-controlled trial study examined the role of respiratory infections and diarrhea in modifying the growth response to vitamin A supplementation. A total of 1405 children aged 6-48 months were given a single high dose of vitamin A or placebo every 4 months, and 4430 child treatment cycles were used in this analysis. The study was conducted in two rural subdistricts located on the southern coast of central Java, Indonesia. Analytic findings indicate that vitamin A supplementation resulted in a modest improvement in the linear and not in the ponderal growth of children. Those who had an adequate intake of 400 RE/day and were free of respiratory infection grew 0.22 cm/4 months (95% CI: 0.08, 0.37) more in height. Conversely, there were no significant growth responses to vitamin A supplementation among children with 21.5% of days or higher of respiratory infection. In addition, children who experienced no respiratory infection and had vitamin A intake below the normative requirement (400 RE/day) gained 0.31 cm/4 months (95% CI: 0.10, 0.52) more in height than the placebo group. Moreover, diarrhea was associated with poorer growth but did not modify the effect of vitamin A supplementation on growth. In conclusion, vitamin A supplementation improves linear growth in children but not among those with a high prevalence of respiratory infections.