Table 6 Prevalence of breast cancer risk factors in the nested case-control study within Singapore Breast Screening Programme (SBSP) cohort and relative risks ( RR ) from SBSP and the Breast Cancer Detection and Demonstration Project (BCDDP)

Women ( n )

439

1,198

1,637

1,637

1,637

5,998

AGEMEN (y)

≥14

246

772

1,018 (62.19)

1

1

1

12–13

173

377

550 (33.60)

1.23

1.27

1.10

<12

20

49

69 (4.22)

1.50

1.61

1.21

AGECAT (y)

NBIOPS

<50

0

2

10

12 (0.73)

–

–

1

1

0

1

1 (0.06)

–

–

1.70

2

–

–

–

–

–

2.88

≥50

0

396

1,109

1,505 (91.94)

–

–

1

1

41

78

119 (7.27)

–

–

1.27

2

–

–

–

–

–

1.62

AGEFLB (y)

NUMREL

<20

0

54

182

236 (14.42)

1

1

1

1

2

5

7 (0.43)

2.17

2.17

2.61

≥2

–

–

–

4.70

4.73

6.80

20–24

0

123

431

554 (33.84)

1.19

1.20

1.24

1

7

11

18 (1.10)

2.57

2.61

2.68

≥2

2

0

2 (0.12)

5.57

5.68

5.78

25–29 or nulliparous

0

172

410

582 (35.55)

1.40

1.44

1.55

1

13

15

28 (1.71)

3.05

3.14

2.76

≥2

–

–

–

6.60

6.83

4.91

≥30

0

62

139

201 (12.28)

1.66

1.73

1.93

1

3

5

8 (0.49)

3.61

3.77

2.83

≥2

1

0

1 (0.06)

7.82

8.20

4.17

BMI (kg/m²)

< 23.0

126

476

602 (36.82)

1

–

–

23.0 – 27.4

207

497

704 (43.06)

1.46

–

–

≥ 27.5

106

223

329 (20.12)

2.14

–

–

PARITY

≥3

263

801

1,064 (65.00)

1

–

–

1–2

112

276

388 (23.70)

1.23

–

–

0

64

121

185 (11.30)

1.50

–

–