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Effect of iron supplementation on incidence of infectious illness in children: systematic review

BMJ 2002; 325 doi: (Published 16 November 2002) Cite this as: BMJ 2002;325:1142
  1. Tarun Gera, senior resident,
  2. H P S Sachdev, professor. (hpssachdev{at}
  1. Division of Clinical Epidemiology, Department of Paediatrics, Maulana Azad Medical College, New Delhi 110002, India
  1. Correspondence to: H P S Sachdev E-6/12, Vasant Vihar, New Dehli 110057, India
  • Accepted 28 June 2002


Objective:To evaluate the effect of iron supplementation on the incidence of infections in children.

Design: Systematic review of randomised controlled trials.

Data sources:28 randomised controlled trials (six unpublished and 22 published) on 7892 children.

Interventions: Oral or parenteral iron supplementation or fortified formula milk or cereals.

Outcomes:Incidence of all recorded infectious illnesses, and individual illnesses, including respiratory tract infection, diarrhoea, malaria, other infections, and prevalence of positive smear results for malaria.

Results: The pooled estimate (random effects model) of the incidence rate ratio (iron v placebo) was 1.02 (95% confidence interval 0.96 to 1.08, P=0.54; P<0.0001 for heterogeneity). The incidence rate difference (iron minus placebo) for all recorded illnesses was 0.06 episodes/child year (−0.06 to 0.18, P=0.34; P<0.0001 for heterogeneity). However, there was an increase in the risk of developing diarrhoea (incidence rate ratio 1.11, 1.01 to 1.23, P=0.04), but this would not have an overall important on public health (incidence rate difference 0.05 episodes/child year, −0.03 to 0.13; P=0.21). The occurrence of other illnesses and positive results on malaria smears (adjusted for positive smears at baseline) were not significantly affected by iron administration. On meta-regression, the statistical heterogeneity could not be explained by the variables studied.

Conclusion:Iron supplementation has no apparent harmful effect on the overall incidence of infectious illnesses in children, though it slightly increases the risk of developing diarrhoea.


  • Editorial by Tomkins

  • Funding None.

  • Competing interests International Life Science Institute (ILSI) sponsored TG for travel to Hanoi, Vietnam for the purpose of attending the International Nutritional Anaemia Consultative Group symposium and presenting part of the analysis as a poster.

  • Accepted 28 June 2002
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