Neonatal vitamin A supplementation associated with increased atopy in girls
In 2013 we conducted a follow-up study on children who at birth had been randomised to neonatal vitamin A supplementation (NVAS) or placebo. In the children now aged 8-10 years, the effect of NVAS on atopy was analysed with skin prick tests and interviews on symptoms of atopic disease. NVAS had no overall effect on atopy among the 1430 children with a valid test, but the effect was sex-differential; NVAS significantly increased the risk of atopy in girls (RR 1.78 [1.17-2.72]) whereas the tendency was opposite in boys. NVAS also increased the risk of wheezing in girls, but not in boys.
In 2002-2004 the Bandim Health Project conducted a randomised controlled trial where 4345 children were randomised to neonatal vitamin A supplementation (NVAS) or placebo at the time of their BCG vaccination. In 2013 we were able to find and 1478 children from the original cohort and conduct a follow-up study on the effect of NVAS on development of atopy defined as skin prick test reaction ≥3mm. Of the 1430 children with a valid skin prick test, 228 (16%) were positive (more boys (20%) than girls (12%), p-value<0.0001). NVAS did not increase the overall risk of atopy (RR 1.10 [95% CI 0.87-1.40]). However, NVAS was associated with significantly increased risk among females (RR 1.78 [1.17-2.72]) but not among males (0.86 [0.64-1.15], p-value for interaction between NVAS and gender=0.005). Furthermore, NVAS was associated with increased risk of wheezing among females (RR 1.80 [1.03-3.17], but not among males, p-value for interaction=0.05).