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Table 1 Study population characteristics

From: Associations between metal concentrations in whole blood and placenta previa and placenta accreta: the Japan Environment and Children’s Study (JECS)

 

Total (N = 16,019)

Previa

Accreta

Without (N = 15,929)

With (N = 90)

p value

Without (N = 15,980)

With (N = 39)

P value

Age (years)

31.3 ± 5.0

31.3 ± 5.0

32.9 ± 4.7

0.003

31.3 ± 5.0

34.1 ± 5.2

0.002

Smoking habits

 Never

9194 (57)

9136 (57)

58 (64)

 

9173 (57)

21 (54)

 

 Former

6002 (37)

5974 (38)

28 (31)

0.224

5989 (37)

13 (33)

1.000

 Current

823 (5)

819 (5)

4 (4)

0.817

818 (5)

5 (13)

0.057

Smoking habits of partner

 Never

4281 (27)

4251 (27)

30 (33)

 

4265 (27)

16 (41)

 

 Former

4339 (27)

4314 (27)

25 (28)

0.501

4326 (27)

13 (33)

0.582

 Current

7399 (46)

7364 (46)

35 (39)

0.122

7389 (46)

10 (26)

0.013

Drinking habits

 No

14,386 (90)

14,307 (90)

79 (88)

 

14,355 (90)

31 (79)

 

 Yes

1633 (10)

1622 (10)

11 (12)

0.485

1625 (10)

8 (21)

0.055

Gravidity

 Primigravida

4758 (30)

4733 (30)

25 (28)

 

4751 (30)

7 (18)

 

 Multigravida

11,261 (70)

11,196 (70)

65 (72)

0.730

11,229 (70)

32 (82)

0.117

Parity

 Nulliparous

6385 (40)

6348 (40)

37 (41)

 

6372 (40)

13 (33)

 

 Multiparous

9634 (60)

9581 (60)

53 (59)

0.829

9608 (60)

26 (67)

0.513

Number of cesarean deliveries

 0

14,576 (91)

14,496 (91)

80 (89)

 

14,542 (91)

34 (87)

 

 1

1111 (7)

1106 (7)

5 (6)

0.833

1108 (7)

3 (8)

0.744

 2

305 (2)

300 (2)

5 (6)

0.030

303 (2)

2 (5)

0.168

  ≥ 3

27 (0)

27 (0)

0 (0)

1.000

27 (0)

0 (0)

1.000

  1. Values are mean ± SD or number (%)
  2. p values for age were obtained using Welch’s t test. p values for other factors were obtained using Fisher’s exact test