Effectiveness and efficacy of zinc for the treatment of acute diarrhea in young children

Intervention trials have shown that zinc is efficacious in treating acute diarrhea in children of developing countries. In a randomized, placebo-controlled trial, we assessed the effectiveness and efficacy of giving 3 Recommended Daily Allowances of elemental zinc to 6- to 35-month-old children with acute diarrhea. Methods. Seventeen hundred ninety-two cases of acute diarrhea in Nepalese children were randomized to 4 study groups. Three groups were blinded and the children supplemented daily by field workers with placebo syrup, zinc syrup, or zinc syrup and a massive dose of vitamin A at enrollment. The fourth group was open and the caretaker gave the children zinc syrup daily. Day-wise information on morbidity was obtained by household visits every fifth day. Results. The relative hazards for termination of diarrhea were 26% (95% confidence interval [CI]: 8%, 46%), 21% (95% CI: 4%, 38%), and 19% (95% CI: 2%, 40%) higher in the zinc, zinc-vitamin A, and zinc-caretaker groups, respectively, than in the placebo group. The relative risks of prolonged diarrhea (duration >7 days) in these groups were 0.57 (95% CI: 0.38, 0.86), 0.53 (95% CI: 0.35, 0.81), and 0.55 (0.37, 0.84); zinc accordingly reduced the risk of prolonged diarrhea with 43% to 47%. Five percent and 5.1% of all syrup administrations were followed by regurgitation in the zinc and zinc-vitamin A group, respectively, whereas this occurred after only 1.3% of placebo administrations. Vomiting during diarrhea was also more common in children receiving zinc. Conclusions. Three Recommended Daily Allowances of zinc given daily by caretakers or by field workers substantially reduced the duration of diarrhea. The effect of zinc was not dependent on or enhanced by concomitant vitamin A administration.