Impact of zinc supplementation on diarrheal morbidity and growth pattern of low birth weight infants in Kolkata, India: A randomized, double-blind, placebo-controlled, community-based study

Objective. To assess the impact of zinc supplementation on diarrheal morbidity and growth pattern of low birth weight ( LBW) infants. Methodology. In a randomized, double-blind, placebo-controlled, community-based study conducted in the Tiljala slum of eastern Kolkata, India, between 1999 and 2001, a birth cohort of 100 LBW infants was randomly allocated into either an intervention group receiving 1 mL daily dose of 5 mg of elemental zinc as zinc sulfate in vitamin B complex-based syrup or a placebo group receiving an identical placebo of 1 mL of vitamin-based syrup from birth up to 1 completed year of age. Active weekly surveillance was conducted for detection of diarrhea. Anthropometric measurements of each child were recorded once every month as close to the child's birth date as possible. Data were analyzed by using statistical software packages SPSSPC + 4.0 ( SPSS, Inc, Chicago, IL) and Epi Info 6.0 ( Centers for Disease Control and Prevention, Atlanta, GA). Results. Among the zinc-supplemented group, diarrheal incidence of 1.36 episodes per child per year were observed, whereas it was 1.93 episodes per child per year among the placebo group, giving a relative risk of 1.4 ( 95% confidence interval: 1.02- 2.00). Linear growth and weight for age showed significant differences between the supplemented and placebo groups only at the end of 1 year. Interestingly, the impact of zinc supplementation was masked to a large extent by the protective action of breastfeeding. Conclusions. The study showed that zinc supplementation had a beneficial impact on the incidence of diarrhea and also weight gain among LBW infants.