Systematic Review and Meta-analysis of Zinc Supplementation and Stunting in Children under 5 years of age

he prevalence of zinc deficiency is 28 % of stunted Egyptian children. Therefore, this study was done to determine whether zinc supplementation strategy is feasible and effective for reducing growth retardation at national level. We conducted literature searches of electronic databases of the international standard randomized control trial number register that reported on the effect of zinc supplementation in infants or children below 5 years old. The findings were pooled using random effects meta-analysis; we followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines during all stages of implementation, analysis, and reporting of these meta-analyses after testing of homogeneity. The final fifty four randomized controlled trials included in the meta-analysis showed the zinc supplementation had a greater effect on height and Height for age z-score in children compared with infants (P-interaction = 0.002 and 0.06, respectively). Among children aged ≥2 years, zinc increased height (N = 7 trials; WMD = 1.37 cm, 95%CI: 0.50–2.25) and, height for age z-score (N = 6 trials; WMD = 0.12, 95%CI: 0.05–0.19). Zinc supplementation significantly increased height (N = 40 trials, WMD = 0.23 cm, 95%CI: 0.09–0.38; I2 = 66.9%) showed 28 of 40 studies (70%) had a positive effect of zinc supplementation among children aged < 5 years old on height in randomized controlled trials and, ten of them were statistically significant. Oral zinc supplementation among children aged from 2-5 years is recommended. However, further studies are needed.