Zinc during and in convalescence from diarrhea has no demonstrable effect on subsequent morbidity and anthropometric status among infants <6 mo of age

BACKGROUND: Preventing illness and improving growth in the first 6 mo of life is critical to reducing infant mortality. Zinc given for 14 d at the start of diarrhea has been shown to decrease the incidence and prevalence of diarrhea and pneumonia and improve growth in the 2-3 mo after, but no trial has been done in infants <6 mo of age. OBJECTIVE: This study sought to assess the effect of 14 d of zinc supplementation on subsequent morbidity and growth among infants 1-5 mo of age living in Pakistan, India, and Ethiopia. DESIGN: Infants with acute diarrhea were randomly assigned to receive zinc (10 mg/d; n = 538) or placebo (n = 536) for 2 wk. Weekly follow-up visits were conducted for 8 wk after the diarrhea episode. Incidence and prevalence of diarrhea and prevalence of respiratory infections including pneumonia were compared between the groups. Changes in weight, length, and corresponding z scores during the 8 wk of follow-up were also compared. RESULTS: One thousand seventy-four infants were enrolled at the start of follow-up. The groups did not differ significantly in the proportion of infants with at least one episode of diarrhea or respiratory infections. Infants who received zinc had more days of diarrhea (rate ratio = 1.20) than did the infants who received placebo. The groups had similar prevalences of pneumonia and overall respiratory infections. No significant differences in the mean changes in weight-for-age, length-for-age, and weight-for-length z scores were observed between the groups overall or in stratified analyses. CONCLUSION: Young infants do not appear to benefit from 2 wk of zinc, unlike what has been observed among older children.