To evaluate the effect of iron supplementation on haemoglobin (Hb) in children through a systematic review of randomised controlled trials.
Electronic databases, personal files, hand search of reviews, bibliographies of books, and abstracts and proceedings of international conferences were reviewed. Randomised controlled trials evaluating change in Hb levels with interventions that included oral or parenteral iron supplementation or iron-fortified formula milk or cereals were analysed.
A total of 55 trials (56 cohorts) provided relevant information. Publication bias was evident (P < 0.001). The pooled estimate (random-effects model) for change in Hb with iron supplementation (weighted mean difference) was 0.74 g/dL (95% CI, 0.61–0.87; P < 0.001; P < 0.001 for heterogeneity). Lower baseline Hb level, oral medicinal iron supplementation, and malarial nonhyperendemic region were significant predictors of greater Hb response and heterogeneity. Projections suggested that, on average, between 37.9% and 62.3% of baseline anaemia (Hb <11 g/dL) was responsive to iron supplementation among children under 6 years of age; the corresponding range for malarial hyperendemic regions was 5.8% to 31.8%.
This systematic review indicates that iron supplementation increases Hb levels in children significantly but modestly. The increase is greater in subjects who are anaemic at the start of the trial and lower in malarial hyperendemic areas and in those consuming iron-fortified food. The projected reductions in prevalence of anaemia with iron supplementation alone highlight the need for additional area-specific interventions, particularly in malaria-prone regions.
*S.L. Jain Hospital
†Division of Clinical Epidemiology, Department of Paediatrics, Maulana Azad Medical College, New Delhi, India
‡HarvestPlus, International Food Policy Research Institute, Washington, DC
§University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India
Received 24 August, 2005
Accepted 19 April, 2006
Address correspondence and reprint requests to H.P.S. Sachdev, E-6/12 Vasant Vihar, New Delhi 110 057, India (e-mail: email@example.com).
T.G. prepared the protocol, applied the search strategy, performed the retrieval of articles, and extracted the data from the included studies. H.P.S.S. and P.N. developed the idea for the review and finalised the protocol and search strategy. H.P.S.S. performed the statistical analysis. S.S.S. helped with the search strategy, data extraction, and statistical analysis. All of the authors contributed to the drafting of the final version of the manuscript. H.P.S.S. and T.G. are the guarantors.
Funding was provided by the US Agency for International Development through its cooperative agreement (No. HRN-A-00-98-00027-00) with the Human Nutrition Institute of the International Life Sciences Institute (ILSI) Research Foundation. The funding source had no influence on the study design, analysis, and interpretation, and the decision to submit for publication.