Table 3

Meta-analysis, subgrouping by age group. SMD analysis of the effect of iron supplementation on cognitive domains

Cognitive domain

Age group

Standardised mean difference (95% CI)

Number of participants/studies

Heterogeneity - I2 test


Attention & concentration

Children aged 6-18

0.62 (0.26 to 0.98)*

132/2 (4 arms)**

0%


Pre-menopausal women

0.53 (-0.06 to 1.12)

47/1

Not relevant


Intelligence

Children aged 6-18

0.02 (-0.22 to 0.27)

2289/4 (9 arms)**

82%


Pre-menopausal women

0.62 (0.15 to 1.10)*

76/2

0%


Memory

Children aged 6-18

0.33 (-0.19 to 0.85)

132/2 (4 arms)**

35%


Pre-menopausal women

0.09 (-0.31 to 0.50)

123/3

18%


Psychomotor

Children aged 6-18

0.19 (-0.17 to 0.54)

132/2 (4 arms)**

0%


Pre-menopausal women

0.09 (-0.32 to 0.50)

123/3

21%


Scholastic aptitude

Children aged 6-18

0.03 (-0.63 to 0.69)

1799/3 (6 arms)**

96%


Pre-menopausal women

0.77 (-0.08 to 1.62)

25/1

Not relevant


* p < 0.05

** Two studies included 3 sets of participants defined by baseline iron status [15,24], and two further studies included 2 sets of participants defined by baseline iron status [21,23], these arms were entered separately into the meta-analysis.

Falkingham et al. Nutrition Journal 2010 9:4   doi:10.1186/1475-2891-9-4

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