A randomised controlled trial to test equivalence between retinyl palmitate and beta carotene for vitamin A deficiency.

摘要

OBJECTIVES--To determine whether beta carotene is therapeutically equivalent to retinyl palmitate in the formulation currently recommended by the World Health Organisation. DESIGN--Randomised blind equivalence trial. SETTING--Rural area in Senegal. SUBJECTS--Children aged 2-15 years suffering from vitamin A deficiency as defined by abnormal results on eye cytology were randomly allocated treatment with retinyl palmitate (n = 256) and beta carotene (n = 254). MAIN OUTCOME MEASURE--Reversion to normal results on eye cytology as defined by the reappearance of goblet cells and normalisation of the epithelial cells. RESULTS--Seven weeks after the supplement was given the percentages were 51.2% (124/242) children taking retinyl palmitate and 50.0% (123/246) of those taking beta carotene, who had reverted to normal eye cytology, a difference of 1.2% (95% confidence interval 6.2% to 8.6%) [corrected]. According to an equivalence testing procedure, the two treatments were statistically equivalent; the null hypothesis of non-equivalence was rejected (one tailed p value = 0.03). CONCLUSIONS--beta Carotene supplementation seems to be a promising candidate for the alleviation of vitamin A deficiency. It could be given either as high dose capsule or through increased dietary intake. The challenge now is to improve dietary intake of vitamin A in programmes that are effective and sustainable at the community level.