Nutrition News for Africa
Abstract - May 15, 2007
An article entitled “Randomized controlled safety and efficacy trial of 2 vitamin A supplementation schedules in Tanzanian infants” was published by Idindili et al. in the American Journal of Clinical Nutrition 2007:85:1312-9
Introduction: There is strong evidence that vitamin A supplementation from the age of 6 months reduces morbidity and mortality in areas with endemic vitamin A deficiency (VAD). Because a high proportion of all child deaths occur before the age of 9 months, the effects of earlier vitamin A supplementation were investigated, with conflicting results. Supplementation of mothers has been shown to improve the vitamin A intake of breastfeeding infants. Combined supplementation of mothers shortly after delivery and of their young children may help improve children’s vitamin A status. The authors conducted a study to compare the safety and efficacy of a previously tested low-dose regimen with those of a suggested high-dose regimen.
Subjects and methods: This 2-arm, randomized, double-blind trial was conducted in Ifakara, in southern Tanzania and was designed to compare the safety and efficacy of 2 vitamin A supplementation regimens. In the low-dose group, mothers received 200 000 IU vitamin A at the time of their infant’s BCG vaccination, and their infants received doses of 25 000 IU at the time of the 3 DPT/OPV vaccinations. In the high-dose group, mothers received an additional dose of 200 000 IU when their infant received the first DPT/OPV vaccination, and their infants received 3 doses of 50 000 IU at the same time as the 3 DPT/OPV vaccinations. In accordance with national guidelines, all infants received 100 000 IU vitamin A at the time of measles vaccination. Mothers who were resident in the study area and brought their infants to the District Hospital and Maternal and Child Health Clinic (MCHC) for BCG vaccination within 7 days of birth were invited to participate in the trial. Before each supplementation, project clinical officers examined mothers or their infants (or both), and a standardized morbidity questionnaire was completed. Mothers were encouraged to bring their infant to a Clinical Surveillance System (CSS) location if the infant experienced any illness during follow-up. Active clinical surveillance was done by fieldworkers who visited mothers and their infants at home for 2 consecutive days after each maternal and infant supplementation.
Results: Recruitment of 780 mother-infant pairs took place from April 2002 to March 2003. Follow-up was completed by the end of 2003. The incidence of all clinical signs of illnesses, symptoms, and diagnoses detected by the CSS did not differ significantly between the 2 groups of infants during all time at risk. Active case detection documented a significantly lower prevalence of fever after the first dose of vitamin A in infants in the high-dose arm than in the infants in the low-dose arm. No similar pattern was seen after other doses. The proportion of infants with inadequate vitamin A liver stores at 6 months was 43% in the high-dose arm and 47% in the low-dose arm. VAD of different severities did not differ significantly between the 2 groups.
Discussion: This trial has shown that supplementation of mothers with a second dose of 200 000 IU vitamin A and of their infants with 50 000 IU at the time of routine vaccinations was safe but not more efficacious than a lower-dose regimen. These results are not what had been expected. The best approach to improving the vitamin A status of young infants remains unclear. The high-dose supplementation regimen the authors evaluated is recommended by the International Vitamin A Consultative Group (IVACG). Although not previously tested in a clinical trial, the recommendation was based on theoretical calculations. The results of this study do not support this current IVACG recommendation. The authors conclude that higher-dose vitamin A supplementation was well tolerated by mothers and infants, but failed to improve the vitamin A status or the incidence of illness episodes in trial participants. The stability of the vitamin A capsules is of great concern and draws attention to the need for quality-assurance checks of such capsules. The authors also recommend specific validation of the biochemical indicators of vitamin A status in very young infants.
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