Table 1

Characteristics of included studies.

Study Name

n

Population

Dose & type of oral iron

Baseline Iron Status

Study duratn, Drop-outs

Cognitive tests*


Beard 2005 [19,45]

Iron 34

Pl 30

S Africa-mothers, 18-30 yrs

Pre-menopausal women

125 mg/d as pills

Anaemic - Hb 9-11.5 g/dl, SF 10-12 μg/L

29 wks, Iron 2

Pl 4

Raven's CPM (IQ), Wechsler's DS (M, Ps)


Bruner 1996 [30,46]

Iron 40

Pl 41

USA-adolescents, school, mean age 16.2 and 15.7

Children 6-18

260 mg/d EFe as capsules

Iron Defic - Hb>11.5 g/dl (Af American), Hb>12 g/dl (white), SF<12 μg/L for all

8 wks,

Iron 1

Pl 2

Visual Search and Attention (AC), Hopkin's Verbal Learning Test (M), DS Modalities (Ps), Attention.


Elwood 1970 [20]

Iron 26

Pl 21

UK - women >20 yrs

Pre-menopausal women

150 mg/d as tablets

Anaemic - HB<10.5 g/dl

8 wks,

Iron 0

Pl 0

Mazes test (AC), Serial Sevens (M), Peg board (Ps), E test, card sorter.


Gopaldas 1985 [21,47-49]

Iron 32

Pl 16

India-School boys-recipients of free noon meal, 8-15 yrs

Children 6-18

30 or 40 mg/d as tablets

Anaemic - Hb<10.5 g/dl, Iron Defic and/or Repl- rest

8.5 wks,

Iron 0

Pl 0

Mazes test (AC), Visual Memory Test (M), Wechsler's Digit span (Ps), Clerical task


Groner 1986 [22]

Iron 19

Pl 19

USA-pregnant women, 14-24 yrs

Pre-menopausal women

60 mg/d EFe as capsules

Iron repl - mean Hb>12 g/dl, SF 40-60 μg/L

4 wks,

Iron 3

Pl 10

Vocab (IQ), DS (M, Ps), Arithmetic (SA), Consonant trigram, Rey AVL, Digit Span


Kashyup 1987 [23,49]

Iron 83

Pl 83

India-School girls, under privileged, 8-15 yrs

Children 6-18

60 mg/d EFe as tablets

Anaemic - Hb<10.5 g/dl, Iron Defic and/or Repl-rest

17.2 wks,

Iron 18

Pl 18

Mazes test (AC), Visual Memory (M), Wechsler's Digit span (Ps), Clerical


Kordas 2005 [32,50,51]

Iron 303

Pl 299

Mexico-school children, mean age 7.0

Children 6-18

30 mg/d as tablets

Iron Defic and/or Repl - Hb>9 g/dl

21 wks,

Iron 38

Pl 49

Distractibility (AC), Peabody PV (IQ), Vis Memory (M), Maths (SA), Sternberg**


Lambert et al., 2002 [27]

Iron 57

Pl 59

New Zealand-female high school students, 12.5-17.9 yrs

Children 6-18

105 mg/d EFe as tablets

Iron defic - Hb>12 g/dl, SF<12 μg/L

8 wks,

5 across whole study

Visual Search and Attention (AC), Hopkin's Verbal Learning (M), Stroop task, Reading span


Lynn & Harland 1998 [15]

Iron 208

Pl 205

England - teenagers at 7 comprehensive schools, 12-16 yrs

Children 6-18

17 mg/d EFe as tablets

Iron Defic - any Hb, SF<12 μg/L ??and??? Iron Repl - the rest

16 wks,

Unclear, ~200 over study?

Raven's CPM (IQ)


Murray-Kolb et al 2007 [31]

Iron 76

Pl 76

USA-Women, aged 18-35 yrs

Pre-menopausal women

60 mg/d EFe as pills

Anaemic - Hb 10.5-11.9 g/dl plus 2 aFeSIs, Iron Defic - Hb = 12 g/dl plus 2 aFeSIs, Iron Repl - Hb = 12 g/dl without 2 aFeSIs

16 wks,

Iron 20

Pl 19

Cog Abilities-attention (AC), Cog Abilities - memory (M), Cog Abilities - learning (SA), Shipley Inst Scale (IQ)


Pollitt 1989 [24]

Iron 678

Pl 678

Thailand-school children, 9-12 yrs

Children 6-18

4 mg/kg/d EFe as tablets

Anaemic Hb<12 g/dl and SF<10 μg/L or TS<16%, Iron Defic Hb>12 g/dl and SF<10 μg/L or TS<16%, Iron Repl - rest

16 wks,

Not reported

Raven's CPM (IQ), Mathematics (SA), Thai language


Soemantri 1985 [29,52]

Iron 59

Pl 60

Indonesia-primary school children, mean age 10.7 to 11.1 yrs

Children 6-18

2 mg/kg/d EFe as tablets

Anaemic - Hb<11 g/dl, TS<15%, Iron Repl - Hb>12 g/dl, TS>20%

13 wks,

Iron 0

Pl 0

Raven's CPM (IQ), Bourden-wisconsin concentration, Maths, Language, Biology, social science


Soemantri 1989 [25]

Iron 71

Pl 59

Indonesia-primary school children, mean age 10.4

Children 6-18

2 mg/kg/d EFe tablets

Anaemic - Hb<11 g/dl, TS<12%, Iron Repl - Hb>12 g/dl. TS <20%

13 wks,

Iron 0

Pl 0

Raven's CPM (IQ), Maths (SA), Language, Biology, social science


Sungthong 2004 [26,53]

Iron/d 112

Iron/wk 102

Pl 99

Thailand-School children, mean age 9.6 to 9.7

Children 6-18

60 mg/d or/wk EFe, tablets

Iron Repl - Hb>8 g/dl, SF>20 μg/L

16 wks,

Iron/d 1

Iron/wk 4

Pl 1

Test of Non-Verbal Intelligence (IQ), Maths (SA), Thai Language


*tests in bold have been used in the analysis

** Plus Figure match & design, Stimulus discrimination, Cognitive abilities, Visual search, Sequencing

Hb: haemoglobin, TS: transferrin saturation, SF: serum ferritin, EFe: elemental iron, aFeSI: abnormal iron status indicators, Pl: placebo, AC: Attention and concentration, IQ: Intelligence quotient, M: memory, Ps: psychomotor, SA: Scholastic Achievement, Raven's CPM: Raven's Colour Progressive Matrices, Peabody PV: Peabody Picture Vocabulary, Rey AVL: Rey Auditory Verbal Learning, Digit Symbol: DS, Repl: repletion, Defic: deficient

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

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