Impact of zinc supplementation on diarrhoeal morbidity in rural children of West Bengal, India

Aim: To determine the role of zinc supplementation in reducing diarrhoeal morbidity in children. Methods: A randomized, double-blind, community-based intervention study was conducted in 280 rural children aged between 6 and 41 mo. Children were randomly allocated into three groups. One group received a daily dose of 10 mg zinc for 5 d wk(-1), another group received 50 mg zinc once weekly and the remaining group received placebo. Zinc was supplemented for 16 wk from November 1999. Diarrhoeal episodes were detected by weekly surveillance during the supplementation period. Results: Eighty diarrhocal episodes were detected among 59 children in all 3 groups. The groups were compared with each other at baseline and as regard to the outcome variable (incidence of diarrhoea). The proportion of children suffering from diarrhoea during the period was significantly lower in the zinc-supplemented groups (15.8% in daily and 16.5% in weekly group) than in the placebo group (30.8%). The incidence of diarrhoea in the daily and weekly zinc-supplemented groups was 0.68 and 0.69 episodes child(-1) y(-1), and that in the placebo group was 1.67 episodes child(-1) y(-1) (relative risk 0.41, 95% confidence interval 0.24-0.71). Diarrhoeal incidence of <4 d duration was found to occur significantly less often in the supplemented groups. There was no difference in diarrhoeal incidence between the daily and weekly zinc-supplemented children. There were no detected adverse reactions in any of the supplemented groups. Conclusion: The study indicates that zinc supplementation is effective in reducing diarrhoeal morbidity when administered either daily or in a weekly schedule.