THE IMPACT OF VITAMIN-A SUPPLEMENTATION ON PHYSICAL GROWTH OF CHILDREN IS DEPENDENT ON SEASON

Objective: To determine the impact of vitamin A supplementation on phy sical growth in young children. Design: Randomized, double blind, plac ebo controlled trial. Setting: Urban slum community clinic. Subjects: 900 children, aged 12-59 months, attending the community clinic with d iarrhea of less than or equal to 7 d were included in the trial. Inter vention: Each child was given a single dose capsule containing 200 000 IU vitamin A or placebo at enrollment. Main outcome measures: Mean in crements in weight and height during the 90 d period post supplementat ion. Results: In all children, the mean increments in weight following supplementation were 0.66 kg (s.d. 0.5) and 0.64 kg (s.d. 0.6) in the vitamin A. and placebo groups (P = 0.5). The mean increments in heigh t were also similar in the two treatment groups (P = 0.5). Serum vitam in A was measured in 40 randomly selected children in each group; the proportion of subclinical deficiency (serum retinol < 20 mu g/dl) was 62.5% in those enrolled during summer (April through July) as compared to 21.2% in those enrolled during the remaining cooler months of the year (P = 0.02). In the children supplemented with vitamin A during su mmer, the mean increment in weight was 140 g more than those who recei ved placebo (95% confidence interval CI 30-250); there was also a sign ificant reduction in the proportion of children who were wasted (< -2 weight-for-height Z-score) at end study (Odds Ratio 0.53, 95% CI 0.28- 1.0, P = 0.03). There was no significant impact of vitamin A on height increments in children supplemented during summer. Conclusion: Vitami n A supplementation in 12-59 month old children improves weight gain i n the subsequent three months only in the summer season, but not durin g the rest of the year.