Table 4

Association between various factors and HER-2/neu+ and HER-2/neu− breast cancer among postmenopausal and pre- or perimenopausal women

PostmenopausalPre/Perimenopausal
HER-2/neu+ cases/Controls n = 53/436 OR (95% CI)aHER-2/neu− cases/Controls n = 233/436 OR (95% CI)aHER-2/neu+ cases/Controls n = 62/354 OR (95% CI)aHER-2/neu− cases/Controls n = 229/354 OR (95% CI)a
Age at menarche
<12 years1.3 (0.6–2.7)1.4 (0.9–2.1)1.4 (0.7–2.7)1.2 (0.8–1.9)
≥12 years1.01.01.01.0
Nulliparity/Age at first full-term pregnancy
Nulliparous2.3 (0.9–5.8)1.4 (0.8–2.6)0.7 (0.3–1.6)0.7 (0.4–1.2)
>25 years1.7 (0.7–4.1)1.3 (0.8–2.1)0.5 (0.2–1.2)0.9 (0.6–1.4)
≤25 years1.01.01.01.0
Abortion or miscarriage
Ever0.8 (0.4–1.5)1.0 (0.7–1.5)1.2 (0.7–2.2)0.8 (0.6–1.2)
Never1.01.01.01.0
Breastfeeding
≥12 months0.1 (0.0–1.1)1.1 (0.6–1.8)0.4 (0.1–1.4)0.7 (0.4–1.2)
<12 months0.9 (0.4–1.9)0.7 (0.5–1.1)0.6 (0.3–1.4)0.6 (0.4–1.0)
Never1.01.01.01.0
Oral contraceptive use
Ever1.1 (0.5–2.2)1.1 (0.7–1.7)0.7 (0.3–1.6)1.3 (0.8–2.1)
Never1.01.01.01.0
Hormone replacement therapy
Ever (≥3 months)0.5 (0.3–1.0)b0.7 (0.5–1.0)b
Never1.01.0
Body mass index
>27.3 kg/m20.6 (0.3–1.3)1.1 (0.7–1.6)0.7 (0.3–1.3)0.8 (0.5–1.2)
≤27.3 kg/m21.01.01.01.0
Waist:hip ratio
>0.81.5 (0.8–3.1)1.2 (0.8–1.8)1.4 (0.7–2.8)1.7 (1.1–2.6)
≤0.81.01.01.01.0
First-degree family history of breast or ovarian cancer
Yes1.8 (0.8–3.9)1.3 (0.8–2.0)1.6 (0.7–3.7)1.6 (1.0–2.8)
No1.01.01.01.0
Medical radiation to the chest
Ever1.1 (0.4–3.1)1.1 (0.6–1.9)1.7 (0.3–9.3)1.1 (0.3–3.6)
Never1.01.01.01.0
Alcohol drinking during most recent age range
Yes0.6 (0.3–1.1)1.0 (0.7–1.4)2.0 (0.9–4.6)0.7 (0.5–1.1)
No1.01.01.01.0
Smoking
Ever (≥5 packs)1.1 (0.6–2.0)1.0 (0.7–1.4)1.0 (0.6–1.9)1.0 (0.7–1.5)
Never1.01.01.01.0
Education
≥College graduate1.0 (0.3–2.8)0.9 (0.5–1.6)1.2 (0.4–3.4)1.3 (0.6–2.6)
≥High school graduate to College graduate1.0 (0.4–2.3)1.0 (0.6–1.5)1.0 (0.4–2.7)1.2 (0.6–2.3)
<High school graduate1.01.01.01.0
  • a Adjusted for all the 13 primary variables simultaneously, as well as race, age at diagnosis/selection (5-year age group), and the offset term.

  • b Including perimenopausal women with postmenopausal women.