Background: Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have important effects on children's psychomotor development and cognitive function.
Objectives: To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient children less than 3 years of age.
Search strategy: The following databases were searched: COCHRANE LIBRARY (2000 ISSUE 4) MEDLINE (1966-August 2000) EMBASE (1980-August 2000) Latin American Database (LILACS) PsycLIT Journal articles (1974-August 2000) PsycLIT Chapters and Books (1987-August 2000) The references of identified trials and of important review articles were scrutinised. Citation searches on trials from the primary search were performed within the Science Citation Index. Key authors were contacted.
Selection criteria: Studies were included if children less than 3 years of age with evidence of iron deficiency anaemia were randomly allocated to iron or iron and vitamin C versus a placebo or vitamin C alone and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation.
Data collection and analysis: Abstracts and titles of studies identified on searches of electronic databases were read to determine whether they might meet the inclusion criteria. Full copies of those possibly meeting these criteria from electronic or other searches were assessed by two independent reviewers. Differences of opinion about suitability for inclusion were resolved by discussion. Data were analysed separately depending on whether participants had iron assessments were performed within one month of beginning iron therapy or later.
Main results: Five trials, including 180 children with IDA, examined the effects of iron therapy on measures of psychomotor development between 5 and 11 days of commencement of therapy. Data from four trials could be pooled. The pooled difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups was -3.2 (95%CI -7.24, 0.85) and in Bayley Scale MDI, 0.55 (95% CI -2.84, 1.75). Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development more than 30 days after commencement of therapy. Aukett et al reported the mean number of skills gained after two months of iron therapy, using the Denver test. The intervention group gained 0.8 (95% CI -0.18, 1.78) more skills on average than the control group. Idjrandinata et al reported that the difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups after 4 months was 18.40 (95%CI 10.16, 26.64) and in Bayley Scale MDI, 18.80 (95% CI 10.19, 27.41).
Reviewer's conclusions: There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development discernable within 5-11 days. The effect of longer term treatment remains unclear but the data would be compatible with clinically significant benefit. There is urgent need for further randomised controlled trials with long term follow up.