Infectious Diseases
Respiratory infections reduce the growth response to vitamin A supplementation
in a randomized controlled trial.
Hadi H; Stoltzfus RJ; Moulton LH; Dibley MJ; West KP
International Journal of Epidemiology 1999 Oct;28(5):874-81 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. |