Table 4

Case-only odds ratios and 95% confidence intervals from logistic regression modelsa of associations between breast cancer tumor subtypes and demographic, reproductive, and lifestyle risk factors, combined LACE and Pathways Studies (n = 2544)

Luminal A (comparison)

Triple negativea

HER2-overexpressinga


n

n

OR

95% CI

n

OR

95% CI


Age at diagnosis (years)

≥ 65 (Ref)

637

68

Ref

---

23

Ref

---

50 to 64

871

115

1.99

0.85, 1.62

45

1.39

0.83, 2.32

< 50

355

105

2.78

1.99, 3.90

25

1.75

0.97, 3.15

Test for trend

P ≤ 0.0001

P = 0.03

Race/ethnicity

White (Ref)

1464

204

Ref

---

60

Ref

---

African American

92

44

3.14

2.12, 4.66

5

1.25

0.49, 3.21

Hispanic

135

21

0.93

0.57, 1.53

13

2.19

1.16, 4.13

Asian

135

12

0.53

0.28, 0.97

12

2.02

1.05, 3.88

Other

37

7

1.28

0.56, 2.94

3

1.95

0.58, 6.52

Menopausal status

Postmenopausal (Ref)

1283

163

Ref

---

57

Ref

---

Premenopausal

406

91

0.84

0.55, 1.27

21

0.65

0.31, 1.33

Family history

No (Ref)

1453

229

Ref

---

80

Ref

---

Yes

410

59

0.95

0.69, 1.29

13

0.62

0.34, 1.13

Age at first full-term pregnancy (years)

Nulliparous (Ref)

335

52

Ref

---

13

Ref

---

< 26

959

163

1.28

0.90, 1.82

61

2.02

1.07, 3.80

≥ 26

567

72

0.93

0.63, 1.38

18

0.86

0.42, 1.79

Parity

Nulliparous (Ref)

335

52

Ref

---

13

Ref

---

1 to 2 children

837

137

1.11

0.78, 1.58

40

1.30

0.68, 2.47

≥ 3 children

691

99

1.18

0.81, 1.72

40

1.82

0.94, 3.53

Lifetime duration of breastfeeding

Never (Ref)

871

148

Ref

---

43

Ref

---

0 to 3 months

255

41

1.04

0.71, 1.52

16

1.29

0.71, 2.35

≥ 4 months

711

97

0.78

0.59, 1.03

32

0.86

0.54, 1.38

Parity among never breastfedb

Nulliparous (Ref)

321

50

Ref

---

12

Ref

---

1 to 2 children

326

59

1.34

(0.87, 2.08)

15

1.52

(0.68, 3.41)

≥ 3 children

224

39

1.68

(1.00, 2.81)

16

3.03

(1.27, 7.23)

Parity among 0 to 3 months breastfedb

1 to 2 children (Ref)

144

25

Ref

---

9

Ref

---

≥ 3 children

108

16

1.16

(0.53, 2.56)

7

1.82

(0.57, 5.80)

Parity among ≥ 4 months breastfedb

1 to 2 children (Ref)

358

52

Ref

---

14

Ref

---

≥ 3 children

352

44

0.99

(0.63, 1.55)

17

1.23

(0.57, 2.66)

Alcohol use

Never (Ref)

709

110

Ref

---

39

Ref

---

Ever

880

129

0.98

0.73, 1.30

40

0.94

0.59, 1.50

Smoking history

Never (Ref)

921

146

Ref

---

51

Ref

---

≤ 10

251

41

0.95

0.65, 1.40

7

0.51

0.23, 1.14

11 to 19

147

21

0.89

0.54, 1.47

8

1.17

0.54, 2.56

≥ 20

531

78

0.98

0.72, 1.34

26

1.05

0.63, 1.73

Hormone replacement therapy (postmenopausal only)

Never (Ref)

314

50

Ref

---

24

Ref

---

Ever

943

112

0.83

0.57, 1.20

33

0.45

0.26, 0.79

Oral contraceptive use

Never (Ref)

647

80

Ref

---

29

Ref

---

Ever

1160

202

0.97

0.72, 1.31

63

1.12

0.69, 1.83

BMI (kg/m2)c

< 25 (Ref)

785

110

Ref

---

39

Ref

---

25 to 29

563

99

1.33

0.98, 1.81

31

1.21

0.74, 1.99

≥ 30

500

77

1.04

0.75, 1.45

23

1.03

0.59, 1.78

BMI (kg/m2) among premenopausalb

< 25 (Ref)

223

39

Ref

---

7

Ref

---

25 to 29

99

28

1.82

1.03, 3.24

7

2.15

0.70, 6.58

≥ 30

81

23

1.97

1.03, 3.77

7

2.51

0.74, 8.51

BMI (kg/m2) among postmenopausalb

< 25 (Ref)

480

59

Ref

---

25

Ref

---

25 to 29

422

60

1.08

0.73, 1.59

18

0.86

0.46, 1.61

≥ 30

372

43

0.76

0.49, 1.17

14

0.76

0.38, 1.51


a Adjusted for age at diagnosis, race/ethnicity, and Pathways/LACE study origin except in models with age at diagnosis or race/ethnicity as main predictors.

b P for interaction not statistically significant (P > 0.05) in any tumor subtype model.

c BMI, body mass index one year pre-diagnosis (LACE) and around diagnosis (Pathways).

CI = confidence interval; HER2 = human epidermal growth receptor 2; OR = odds ratio.

Kwan et al. Breast Cancer Research 2009 11:R31   doi:10.1186/bcr2261

Open Data