Impact of zinc supplementation on mental and psychomotor scores of children aged 12 to 18 months: a randomized, double-blind trial

Abstract

Objective: To evaluate the effect of zinc supplementation on mental and psychomotor scores in children aged 12 to 18 months. Study design: In this double-blind, randomized, placebo-controlled trial, children aged 6 to 30 months received daily elemental zinc (10 mg for infants and 20 mg for others) or placebo for 4 months. Bayley Scales of Infant Development II were used for development assessment in the 12- to 18-month subgroup at enrollment and the end of the study. Results: At the end of the study, the adjusted mean mental (P = 0.36) and psychomotor (P = 0.28) index scores were similar in the intervention and control groups. In a multivariate model, the baseline mental development index score was positively associated with the mother's schooling, the child's height for age, packed cell volumes, hospital birth, and attendance at a day care center, and was negatively associated with the child's age. Breastfeeding, the child's weight for height, and packed cell volumes were positively associated with the baseline psychomotor index score. Conclusion: Zinc supplementation did not affect the mental or psychomotor development index scores in a setting in which zinc deficiency is common.