Effect of iron supplementation on physical growth in children: systematic review of randomised controlled trials.

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.