Effect of an infection on vitamin A status of children as measured by the relative dose response (RDR).

The effect of an infective episode of chickenpox on the vitamin A status of preschool-aged children was evaluated by use of the relative dose response (RDR) test. Status was determined before and 30, 120, and 180 d after administration of a single oral high-dosage (200,000 IU) supplement of vitamin A. No differences in mean blood levels of retinol or percentage of children showing a positive RDR were apparent until after the infective episode that occurred approximately 90 d after dosing. At 180 d postsupplementation, 74% of children who had been infected tested positive by the RDR, indicative of an inadequate liver reserve of vitamin A, in contrast to only 10% who had not been infected. Paired RDR observations at 0 and 180 d postsupplementation confirmed that the infective episode caused an accelerated depletion of liver reserves of vitamin A.