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. 2025 Aug 21;26:152. doi: 10.1186/s40360-025-00984-2

Table 1.

Study characteristics of included studies

Authors, Year
Country
Study design Participants Type of iron & Days Daily group Alternate group
Daily group Alternate Dose (f) Hb level (before) Hb level (after) Dose (f) Hb level (before) Hb level (after)
Total
M: F
Age (Yr) BMI Type Total
M: F
Age (Yr) BMI Type
Jongkraijakra et al., 2023 Thailand RCT 7:25 49 ± 15 23.7 ± 4.7 Anaemic 6:26 49 ± 16 25.0 ± 5.5 Anaemic

ferrous fumarate

Week12

200 mg 8.0 ± 1.6 12.4 ± 1.9 200 mg 8.1 ± 1.9 11.9 ± 1.1
Kaundal et al., 2020 India RCT 5:26 37.1 ± 12.3 - Anaemic 3:28 34.3 ± 12.4 - Anaemic

Ferrous sulfate

6weeks

60 mg iron 8.9 ± 1.3 11.8 ± 1.7 120 mg iron 8.9 ± 1.6 10.9 ± 1.3
Kaynar et al., 2022 Turkey RCT F40 35.6 ± 8.3 - anaemic F43 35.8 ± 8.4 - anaemic

iron sulfate

2 months

2*80 mg 9.7 ± 1.2 13.2 ± 0.9 2*80 mg 10.1 ± 1.5 13.3 ± 0.7
Kron et al., 2023 Canada RCT 4:20

(mean ± SD

47.2 ± 18.1

(mean ± SD

25.9 ± 6.7

anaemic 6:21 44.4 ± 17.1 27.0 ± 7.0 anaemic

Ferrous sulfate

12 weeks

300 mg (60 mg elemental iron 11 ± 1.3 13.2 ± 1.7 300 mg (60 mg elemental iron 11 ± 1 12.6 ± 1
McCormick et al., 2020 Australia Parallel-group RCT 6:9 26 ± 6 - healthy 3:13 26 ± 5 - healthy

Ferrous sulfate

8weeks

105 mg of elemental iron

15.71 ±

2.46

16.48±

2.38

105 mg of elemental iron

13.42±

2.56

13.22±

1.6

Mehta et al., 2020 India Prospective RCT 11:9 34 ± 6.67 - Anaemic 12:8 33.7 ± 7.36 - Anaemic

Ferrous sulfate

Day 21

60 mg iron 10.05 ± 1.38 10.46 ± 1.63 60 mg iron 9.6 ± 1.84 11.18 ± 1.31
Oflas et al., 2019 Turkey Prospective RCT F50 34.06 ± 9.593 - Anaemic F50 33.2 ± 9.373 - anaemic

Ferrous sulfate

1 month

80 mg iron 10.48 ± 1.38 g/dL 12.76 ± 0.97 g/dL 80 mg iron 10.31 ± 1.23 g/dL 12.35 ± 1.07 g/dL
Pasupathy et al., 2023 India RCT 98 45.33 ± 17.31 - anaemic 96 49.23 ± 15.71 - anaemic

Ferrous sulfate

8 weeks

60 mg elemental iron 6.68 ± 1.89 8.01 ± 1.8 60 mg elemental iron 6.53 ± 1.89 7.59 ± 1.58
Siebenthal et al., 2023 Switzerland RCT F75 26 (21–29) 21.7 (2.3) anaemic F75 24 (21–28) 21.3 (2.1) anaemic

Ferrous sulfate

186 days

100 mg iron 13.3 ± 0.8 13.4 ± 0.8 100 mg iron 13.3 ± 0.8 13.4 ± 0.8
Stoffel et al., 2017 Switzerland RCT F 21 22 years (IQR 21–25) - anaemic F19 22 years (IQR 21–24) - anaemic

Ferrous sulfate

28 days

60 mg iron Mean SD 12·8 (11·7, 14·0) 13·2 (12·5, 14·0) 60 mg iron

Mean SD

13·2 (12·5, 14·0)

13·6 (12·9, 14·4)
Zavaleta et al., 2000 Peru RCT F101 15.3 ± 1.6 21.5 ± 3.0 healthy F98 15.1 ± 1.6 21.3± 2.9 healthy

Ferrous sulfate

17 wk

60 mg iron 12.6 ± 0.94 13.71 ± 0.94 60 mg iron 12.74 ± 0.89 13.43 ± 0.89

n = number of participants; SD = standard deviation; M = male; F = female; Yr = year; mg = milligram; f = frequency; Hb = haemoglobin; BMI = body mass index; wk = week; IQR = inter quartile range; RCT = randomized control trial;