By Will Boggs, MD
NEW YORK (Reuters Health) Jun 04 - Zinc supplements reduce diarrhea morbidity in six- to 11-month-old infants in populations with high prevalence of wasting and stunting, researchers from India report.
"Physicians, especially those working in primary health care settings and in regions where zinc deficiency is prevalent, should consider short-course zinc prophylaxis," Dr. Akash Malik from Maulana Azad Medical College, New Delhi, India, told Reuters Health.
"Children from low socio-economic and other disadvantaged groups are likely to suffer from under-nutrition and high incidence of diarrhea and may benefit from this intervention."
Zinc supplementation has been shown to reduce the incidence and severity of diarrhea, but the benefits of short-term prophylaxis has been demonstrated only in children over 12 months of age.
Dr. Malik and colleagues tested a two-week course of zinc in a randomized, placebo-controlled study of 272 infants between the ages of six and 11 months.
In a paper online June 3 in Pediatrics, the authors report on 134 infants in the zinc group and 124 in the placebo group who completed the study. Nineteen infants in the zinc group and 26 infants in the placebo group were given an additional week to complete the intervention when they were found to be noncompliant initially.
At the end of five months, the incidence of diarrhea was 39% lower with zinc vs placebo (6.07 vs 9.90 episodes per child-year) after adjusting for wasting.
In subgroup analyses, zinc treatment was associated with significant decreases in acute diarrhea (a 31% reduction), persistent diarrhea (a 70% reduction), and dysentery (a 97% reduction).
Overall days with diarrhea were 39% fewer with zinc than with placebo (mean, 10.10 vs 23.19 days; p<0.001), and the duration per episode of diarrhea was 36% shorter with zinc (mean, 3.60 vs 5.34 days; p <0.001).
The percentage of patients experiencing diarrhea, vomiting, and constipation (the main side effects) did not differ significantly between the zinc and placebo groups.
"The major limitation of this study is that serum zinc levels were not done to assess the deficiency and the subsequent effect on serum zinc levels," the researchers note. "Nevertheless, previous studies in similar populations of Delhi have shown high prevalence of zinc deficiency."
"Currently WHO recommends two weeks zinc only as a therapeutic supplementation," Dr. Malik said. "The current study has shown that even short course zinc prophylaxis of two weeks can significantly reduce diarrheal morbidity in subsequent months. Thus zinc prophylaxis for two weeks may be introduced as a cost effective community based intervention for reducing diarrheal morbidity in zinc deficient populations."
"It is difficult to recommend any age on the basis of a single study," Dr. Malik said. "However 20 mg zinc has been approved by WHO and found to safe for children of six months and above. Initiation of prophylaxis at six months is most crucial, as (this) age group of six months to 11 months suffers from maximum burden of diarrhea, though some studies have initiated it as early as from birth but at much lower doses."
Dr. Malik added, "It is essential to map out zinc deficient populations and conduct similar studies in such populations especially in children of less than one year of age who suffer from maximum burden of diarrhea. For example WHO considers populations with stunting >20% to be zinc deficient. Further studies should be done using a standardized methodology regarding dosage and duration of zinc supplementation so that a strong evidence base can be made available for the policy makers."
Reuters Health Information © 2013