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Table 4 Meta-analyses for vitamin D concentration (IU/L)

From: Calcium, zinc, and vitamin D in breast milk: a systematic review and meta-analysis

Group

Vitamin D

25OHD

Total ARA

N

n

Mean (95% CI)

pa

N

n

Mean (95% CI)

p

N

n

Mean (95% CI)

p

All studies

20

2400

17 (13, 20)

NA

24

2470

80 (66, 93)

NA

19

2162

58 (45, 70)

NA

All studies without outliers

18

2364

18 (14, 22)

20

2013

50 (41, 59)

18

2146

60 (49, 72)

Infant age

            

0–5.9 months

14

1404

12 (9, 14)

0.053

21

1870

115 (92, 138)

< 0.001

20

1777

65 (55, 75)

< 0.001

6–11.9 months

2

172

6 (-3, 15)

1

69

81 (79, 83)

3

124

125 (21, 230)

12–35.9 months

0

0

-

2

70

51 (-30, 133)

0

0

-

Unspecified

7

918

23 (13, 33)

5

312

46 (23, 69)

4

210

22 (6, 37)

Vitamin D supplementation

            

Supplemented

6

620

11 (8, 14)

0.007

7

659

137 (85, 189)

0.032

10

968

91 (73, 109)

< 0.001

Not supplemented

9

589

8 (4, 11)

8

389

71 (39, 103)

9

543

48 (34, 63)

Unspecified/Mixed

10

1293

21 (13, 29)

15

1295

64 (49, 79)

9

592

36 (24, 49)

Country income category

            

Low

1

41

35 (27, 44)

< 0.001

2

62

26 (-5, 56)

< 0.001

1

41

82 (73, 92)

< 0.001

Lower-middle

3

290

24 (11, 36)

1

101

32 (29, 34)

1

101

46 (42, 51)

Upper-middle

4

315

15 (3, 26)

3

465

1219 (1069, 1368)

1

20

14 (11, 17)

High

19

1754

15 (12, 18)

22

1842

61 (48, 74)

20

2000

56 (44, 67)

Continent

            

Africa

1

41

35 (27, 44)

< 0.001

2

62

26 (-5, 56)

< 0.001

1

41

82 (73, 92)

< 0.001

Asia

11

1211

16 (10, 21)

8

850

143 (107, 178)

8

921

37 (26, 48)

Australasia/Oceania

2

166

4 (-4, 12)

2

166

22 (-21, 66)

2

166

26 (-24, 77)

Europe

8

748

18 (13, 23)

9

1245

127 (91, 163)

5

774

75 (54, 97)

North America

5

234

22 (14, 29)

7

147

49 (37, 62)

7

260

70 (44, 96)

Season

            

Fall

2

54

45 (-32, 122)

0.053

1

40

58 (48, 68)

0.055

1

40

63 (53, 73)

< 0.001

Spring

2

99

10 (6, 15)

1

85

50 (42, 58)

1

85

58 (50, 66)

Summer

3

313

9 (4, 13)

3

262

88 (60, 116)

2

256

117 (108, 126)

Winter

4

434

5 (4, 6)

3

381

60 (39, 82)

3

381

66 (45, 87)

Measurement method

            

HPLC and CPBA

7

489

16 (11, 22)

0.293

9

550

51 (39, 64)

< 0.001

8

517

68 (46, 91)

0.360

LC-MS/MS

7

852

13 (8, 18)

8

1315

60 (39, 80)

9

1558

50 (29, 71)

Other

6

1059

22 (11, 32)

7

605

497 (409, 585)

2

87

66 (56, 75)

  1. a P-value for difference between groups. NA: Not applicable, N: number of studies, n: number of participants
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International Breastfeeding Journal

ISSN: 1746-4358