Vitamin A supplementation and increased prevalence of childhood diarrhoea and acute respiratory infections

Abstract

There is uncertainty over whether vitamin A supplementation reduces morbidity among children with subclinical deficiency of the vitamin. Hence a double-blind, placebo-controlled trial of the effect of vitamin A supplementation on childhood morbidity was conducted among 11,124 children aged 6-83 months in the northwest of Haiti. After a random start, children were sequentially assigned by household units to receive either megadose vitamin A or placebo in three distribution cycles 4 months apart. 2 to 8 weeks after each administration of the vitamin A and placebo capsules, indicators of childhood morbidity were reassessed through interviews conducted in the homes of participating families. The vitamin A group was found to have an increased 2-week prevalence of all symptoms and signs of childhood morbidity assessed, including diarrhoea (rate ratio [RR] = 1.09, 95% confidence interval 1.05-1.14), rhinitis (RR = 1.02, 95% confidence interval 1.00-1.04), cold/flu symptoms (RR = 1.04, 95% confidence interval 1.01-1.06), cough (RR = 1.07, 95% confidence interval 1.03-1.11), and rapid breathing (RR = 1.18, 95% confidence interval 1.09-1.27). The study shows an increased 2-week prevalence of diarrhoea and the symptoms of respiratory infections after vitamin A supplementation.

PIP: In the late 1980s, 11,124 children 6-83 months old, living in the sparsely populated northwest of Haiti participated in a double-blind, placebo-controlled trial of the effect of vitamin A supplementation on child morbidity. An ophthalmic assistant and a supervising ophthalmologist examined all children 2 years old. 30 children had vitamin A deficient related corneal disease (20 with corneal xerosis and 10 with corneal ulceration, keratomalacia, and/or corneal scarring). The children received either a capsule containing 200,000 IU of vitamin A and 40.6 mg vitamin E or a capsule containing only 40.6 mg vitamin E (placebo) every 4 months. Field workers interviewed caretakers 2-8 weeks after the children received their capsules to gather data on signs and symptoms of illness. Children in the vitamin A group were more likely to have a higher prevalence of diarrhea and of respiratory infections than the placebo group (e.g., 1st cycle, 42 vs. 36% for diarrhea and 18 vs. 15% for rapid breathing, rate ratios = 1.6 and 1.19, respectively). The risk of morbidity was highest 8-17 weeks after receiving the megadose of vitamin A. These findings indicate that prevalence of diarrhea and respiratory infections increased 2 weeks after vitamin A supplementation. Mortality rates of the 2 groups were essentially the same. The mortality rate of nonparticipants was higher than that of participants (52/1000 vs. 23/1000), however, suggesting that the supplements may have had some benefit.