Vitamin A and survival in children

Vitamin A supplementation in children aged 6 months to 5 years has been shown to reduce mortality by 24- 30 %. The benefit of supplementing young infants less than 6 months of age is less obvious. It may be that the lack of beneficial effects could be due to differences in the effect of supplements by sex. Three previous trials found that neonatal vitamin A supplementation may have a beneficial effect on mortality in boys but no effect in girl A recent study has found that sex differences in the effects of vitamin A on mortality depend on the different dosages of vitamin A, and a lower dosage may be beneficial among girls.
The possible mechanisms are not understood, but they could be due to sex-related differences in the developing immune system or the degree of micronutrient deficiencies by sex
Children born to HIV -infected women are at a high risk of mortality; however, no studies have examined sex differential effects of vitamin supplement among children born to HIV-infected mothers. Nearly, 2 million children were infected with HIV and 270000 died of AIDS worldwide in 2007. Almost 90 % of all HIV -infected children live in sub-Saharan Africa.
Kawai et al had previously reported that maternal multivita¬min supplements showed no effect on overall mortality among children born to HIV-infected mothers in Tanzania.
Vitamin A plus β-carotene alone increased the risk of vertical HIV transmission.
In this study the authors have examined whether there are sex differences in the effect of vitamin supplements on birth outcomes, mortality and morbidity by 2 years of age among children born to HIV-infected women in Tanzania. A randomised placebo-controlled trial was conducted among 959 mother-infant pairs. HIV-infected pregnant women were randomly assigned to receive a daily oral dose of one of four regimens: multivitamins (vitamins B-complex, C and E), vitamin A plus β carotene, multivitamins including vitamin A plus β carotene or placebo. Supplements were administered during pregnancy and continued after delivery. The beneficial effect of multivitamins on decreasing the risk of low birth weight was stronger among girls than among boys . Maternal multivitamin supplements resulted in 32 % reduction in mortality among girls whereas no effect was found among boys . Multivitamins had beneficial effects on the overall risks of diarrhoea that did not differ by sex. Vitamin A plus β carotene alone increased the risk of HIV transmission, but had no effects on mortality, and they found no sex differences in these effects.
Kawai et al 2010 Sex differences in the effects of maternal vitamin supplements on mortality and morbidity among children born to .HIV-infected women in Tanzania Brit Journal Nutrition vol 103, 1784-1791

Martin Eastwood
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