Skip to main content

Table 2 Multivariable adjusted odds ratio (OR) and 95% confidence interval (CI) for ER/PR/HER2-defined subtypes of breast cancer associated with reproductive factors

From: Reproductive factors and the risk of triple-negative breast cancer in white women and African-American women: a pooled analysis

 

Controls

Triple-negative

Luminal A-like

Luminal B-like

HER2-enriched

N

N

OR (95% CI)

N

OR (95% CI)

N

OR (95% CI)

N

OR (95% CI)

All women

 Age at menarche, years

   ≤ 12

1292

289

1.00

820

1.00

186

1.00

110

1.00

  13

634

158

1.13 (0.90–1.41)

419

0.98 (0.84–1.16)

99

1.06 (0.81–1.40)

66

1.22 (0.88–1.69)

   ≥ 14

522

107

0.89 (0.69–1.14)

278

0.77 (0.64–0.92)

75

0.92 (0.68–1.24)

51

1.07 (0.75–1.53)

  Trend P value

0.55

 

0.009

 

0.70

 

0.56

   P value for homogeneity of trends

0.19

      

 Number of completed pregnancies

  Never pregnant

250

68

1.00

224

1.00

56

1.00

31

1.00

  Any completed pregnancies

1990

431

0.91 (0.67–1.24)

1104

0.79 (0.64–0.98)

263

0.82 (0.58–1.15)

176

0.78 (0.50–1.20)

  1

399

98

0.95 (0.66–1.36)

277

0.92 (0.71–1.19)

84

1.17 (0.79–1.74)

50

1.02 (0.62–1.67)

  2

709

168

0.98 (0.70–1.37)

438

0.81 (0.64–1.02)

109

0.88 (0.61–1.29)

59

0.69 (0.42–1.11)

  ≥3

882

165

0.84 (0.60–1.19)

389

0.64 (0.50–0.81)

70

0.53 (0.35–0.80)

67

0.65 (0.40–1.05)

  Trend P value

  

0.26

 

<0.0001

 

<0.0001

 

0.02

   P value for homogeneity of trends

0.09

      

Only non-completed pregnancy

208

55

0.91 (0.60–1.38)

189

1.02 (0.76–1.35)

41

0.88 (0.55–1.39)

20

0.69 (0.38–1.26)

Parous women onlya,b

 Age at first completed pregnancy, years

  ≤20

799

165

1.00

297

1.00

69

1.00

62

1.00

  21–24

510

107

1.03 (0.78–1.38)

274

1.22 (0.98–1.52)

63

1.18 (0.80–1.73)

43

1.05 (0.68–1.62)

  25–29

348

85

1.08 (0.77–1.52)

275

1.64 (1.28–2.10)

56

1.22 (0.78–1.89)

33

1.10 (0.66–1.85)

  ≥30

333

73

0.80 (0.54–1.20)

256

1.17 (0.88–1.55)

75

1.09 (0.68–1.74)

38

0.96 (0.55–1.70)

  Trend P value

  

0.50

 

0.05

 

0.57

 

0.95

   P value for homogeneity of trends

0.24

      

 Duration of breastfeeding, months

  Never

748

166

1.00

370

1.00

81

1.00

60

1.00

  Ever

1242

264

0.80 (0.63–1.02)

732

0.78 (0.65–0.94)

182

0.89 (0.65–1.23)

116

0.91 (0.63–1.32)

    < 6

541

134

0.96 (0.74–1.26)

303

0.83 (0.68–1.02)

82

0.99 (0.70–1.41)

35

0.68 (0.43–1.07)

   6–11

263

40

0.55 (0.37–0.82)

165

0.76 (0.59–0.99)

35

0.70 (0.44–1.12)

33

1.28 (0.78–2.09)

    ≥ 12

438

90

0.69 (0.50–0.96)

264

0.71 (0.56–0.90)

65

0.85 (0.56–1.30)

48

1.10 (0.69–1.75)

  Trend P value

  

0.006

 

0.004

 

0.28

 

0.36

   P value for homogeneity of trends

0.08

      
  1. Models in multivariate analysis included sub-study (the Women’s CARE Study or the Women’s BCIS Study, the Women’s LIFE Study), study site (Los Angeles, Detroit), race (white, African-American), reference age (in 5-year age categories), education (≤ high school, technical school or some college, college graduate), first-degree breast cancer family history (no, yes), body mass index (<25, 25–29, ≥30 kg/m2), a variable combining menopausal status and hormone therapy use (premenopausal; postmenopausal: never used hormone therapy, ever used hormone therapy; unknown menopausal status), lifetime recreational physical activity (inactive, ≤2.2, 2.3–6.6, 6.7–15.1, ≥15.2 annual metabolic equivalents of energy expenditure, hour/week), alcohol intake (never, former, current), cigarette smoking status (never, former, current), age at menarche (≤12,13, ≥14 years), number of completed pregnancies (never pregnant, 1, 2, ≥3, only non-completed pregnancy), oral contraceptive use (never, <1, 1–4, 5–9, ≥10 years). aModels additionally included age at first completed pregnancy (≤20, 21–24, 25–29, ≥30 years) and duration of breastfeeding (never, <6, 6–11, ≥12 months). bAdditionally seven parous case participants who had missing information on breastfeeding were excluded. Triple negative = estrogen receptor (ER)–/progesterone receptor (PR)–/human epidermal growth factor receptor-2 (HER2)–, Luminal A-like = ER+ and/or PR+ plus HER2–, Luminal B-like = ER+ and/or PR+ plus HER2+, HER2-enriched = ER–/PR– /HER2 + 
Back to article page

Breast Cancer Research

ISSN: 1465-542X

Contact us