Effect of zinc supplementation on pneumonia morbidity among low socio-economic, preschool children in india

A double blind, trial was conducted to determine the effect of zinc supplementation on pneumonia morbidity, 609 children (298 zinc. 311 control). 6-35 months of age were randomly allocated to receive zinc 10mg or control preparation daily for 6 months. Morbidity was assessed by every fifth day home visitation. At each visit if cough was present respiratory rate was counted twice for 1 minute and lower chest indrawing was observed. WHO criteria were used for defining pneumonia, two disease free visits separated a new episode. Treatment as per WHO recommendations was provided. For each child monthly follow-up was treated as a unit, incidence of pneumonia was estimated as binary variable within each month. Logistic regression using generalized estimating equation (GEE) were used to estimate relative risks. A significant increase (23.6 vs 0.06 ug/dl) in zinc levels in supplemented as compared to control children indicated successful supplementation (p< 0.001). Zinc supplementation was associated with more days of cough.Zinc supplementation resulted in 18% (95% CI 9 to 43) reduction in days with pneumonia and a 15% (95% Cl -14 to 36) reduction in incidence of pneumonia which was not statistically significant. In the children with plasma zinc levels < 60 μg/dl the reduction is incidence was 28% (95% CI -9 to 53). In conclusion zinc supplementation had a significant impact on pneumonia prevalence. Though we detected a clinically important reduction in incidence of pneumonia, we did not have adequate sample size for effect of such a magnitude to be statistically significant.