Objective: To evaluate the effect of iron supplementation on physical growth in children through a systematic review of randomised controlled trials (RCTs).
Data sources: Electronic databases, personal files, and hand search of reviews, bibliographies of books, abstracts and proceedings of international conferences.
Review methods: RCTs evaluating change in anthropometry with interventions that included oral or parenteral iron supplementation, or iron-fortified formula milk or cereals, were analysed.
Results: Twenty-five trials (26 cohorts) had relevant information. There was no evidence of publication bias. The pooled estimates (random effects model) did not document a statistically significant (P>0.05) positive effect of iron supplementation on any anthropometric variable (weight-for-age, weight-for-height, height-for-age, mid upper-arm circumference, skinfold thickness, head circumference). Significant heterogeneity was evident, and its predictors included greater weight-for-age in supplemented children in malaria hyperendemic regions and greater weight-for-height for children above 5 years of age, but a negative effect on linear growth in developed countries and with supplementation for 6 months or longer.
Conclusions: This review did not document a positive effect of iron supplementation on the physical growth of children. The identified predictors of heterogeneity should be considered as exploratory and requiring confirmation, not conclusive.