Effect Of Supplemental Zinc On The Growth And Serum Zinc Concentrations Of Preterm And Low Birth Weight Infants: A Systemic Review And Meta-analysis

Background: Zinc plays an important role in cellular growth,cellular differentiation and metabolism.Because of periods of rapid growth children are at an increased risk of deficiency.Multiple studies have been carried out to assess the effect of zinc supplementation on children's growth but few of has been done on preterm and low birthweight infants.The results of these studies are inconsistent,and the factors responsible for these varied outcomes are unknown.Objective: This paper presents a systematic review and meta-analysis of the randomised controlled trials(RCTs)that assess the effect of zinc supplementation on the physical growth and serum zinc concentrations in preterm and low birth weight infants.Study population included preterm and LBW infants irrespective of gestational status who were exclusively breastfed,on formula or mixed feeding at the initiation of intervention.Intervention comprised zinc salts given as tablets or syrups orally to provide at least 1 recommended daily allowance of elemental zinc for at least a period of 8 weeks,introduced within one month of birth.Design: Out of 412 studies identified through electronic searches and reference lists,10 RCTs were selected after applying the exclusion/inclusion criteria.The influence of Zn supplementation on growth and serum zinc concentration was considered in the overall metaanalysis.From each select growth study,measures of Weight,Length,mid upper arm circumference(MUAC),Head circumference,Weight for age z-score(WAZ),Length for age zscore(LAZ)and Weight for Length z-score(WLZ)were assessed.Weighted mean effect sizes and 95% confidence interval(CI)were calculated by using fixed-effects model.Results: Zinc supplementation produced highly significant,positive responses in weight,length,head circumference and MUAC increments,with effect sizes of 378.21(95% CI 269.79 to 486.63),1.69(95% CI 0.65 to 2.72),0.55(95% CI 0.29 to 0.81),0.45(95% CI 0.20 to 0.70),respectively.There was no significant effect of zinc supplementation on weight-for-age,lengthfor-age and weight-for-length indexes with effect size of 0.22(95%Cl-0.08 to 0.53),-0.03(95% CI-0.87 to 0.82),0.35(95% CI-0.03 to 0.73)respectively.Zinc supplementation caused a large increase in the children's serum zinc concentrations,with an effect size of 24.68(95% CI 19.24 to 30.11).Conclusions: Interventions to improve children's zinc nutriture should be considered in populations at risk of zinc deficiency e.g.preterm and low birthweight infants...