Daily iron supplementation improved cognitive, physical performance in children with anemia

Low M. Can Med Assoc J. 2013;doi:10.1503/cmaj.130628.

  • November 4, 2013

Children with anemia who received daily iron supplementation demonstrated improved cognitive performance and physical outcomes with few adverse effects, according to results of a systemic review and meta-analysis.

Daily iron supplementation also improved hematologic outcomes, reducing the risk for anemia by 50% and the risk for iron deficiency by 79%.

Researchers used electronic databases, including MEDLINE and Embase, to search for randomized and quasi-randomized trials that evaluated the effects of daily iron supplementation in children aged 5 to 12 years.

Their analysis included 32 relevant studies, 31 of which were conducted in low- or middle-income settings. The most common study site was India (n=7), followed by Thailand (n=4), Indonesia (n=2) and Kenya (n=2).

The studies included a combined 7,089 children. Of them, 3,837 received oral iron supplementation at least 5 days per week. The other 3,252 children served as controls.

Nine of the studies assessed global cognitive performance.

Results showed children who received iron supplementation demonstrated higher global cognitive scores at the end of the intervention period compared with controls (standardized mean difference [SMD]=0.50; 95% CI, 0.11-0.90). Researchers also observed improvement among children who were anemic at baseline (SMD=0.29; 95% CI, 0.07-0.51).

IQ scores also improved in children with anemia who received iron supplementation (mean difference [MD]=4.55; 95% CI, 0.16-8.94).

All children who received iron supplementation demonstrated improvements in age-adjusted height, and those with anemia who received daily supplementation demonstrated improvements in age-adjusted weight.

Seven studies that included 1,763 children showed daily iron supplementation reduced risk for anemia (RR=0.50; 95% CI, 0.39-0.64). Four studies that included 1,020 children showed daily supplementation reduced risk for iron deficiency (RR=0.21; 95% CI, 0.07-0.63).

Researchers found that children who received iron were not at increased risk for malaria or gastrointestinal adverse effects compared with children who did not receive supplementation.

“Anemia and iron deficiency were prevalent in the included studies (69% and 59%, respectively, in the control groups. Thus, routine daily iron supplementation is likely to benefit cognitive performance in primary school-aged children in developing settings where anemia is prevalent and testing hemoglobin before iron supplementation may not be feasible,” the researchers wrote. “Daily iron supplementation could benefit educational attainment and economic potential at the individual level and, in settings where anemia is prevalent, population level.”

Disclosure: The researchers report no relevant financial disclosures.