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. Author manuscript; available in PMC: 2014 Oct 1.
Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2013 Aug 15;22(10):1853–1861. doi: 10.1158/1055-9965.EPI-13-0560

Table 3.

Adjusted Oddsa for TNBC and HER2+ Compared to Luminal A Tumors and Reproductive and Hormonal Factors

Luminal A n = 571 HER2+ n = 225 TNBC n = 159

No. (%) No. (%) OR (95% CI) No. (%) OR (95% CI)

Age at diagnosis, y
 < 50 250 (43.8) 93 (41.3) 1.00 93 (58.5) 1.00
 50 to 59 169 (29.6) 73 (32.4) 1.17 (0.81–1.68) 30 (18.9) 0.44 (0.28–0.70)
 ≥ 60 152 (26.6) 59 (26.2) 1.05 (0.71–1.56) 36 (22.6) 0.57 (0.36–0.88)
 Per 5 y 1.01 (0.95–1.08) 0.89 (0.83–0.96)
Age at menarche, y
 < 13 261 (45.7) 104 (46.2) 1.00 64 (40.5) 1.00
 ≥ 13 310 (54.3) 121 (53.8) 0.98 (0.71–1.33) 94 (59.5) 1.27 (0.88–1.82)
 Per 5 y 0.93 (0.58–1.50) 1.64 (0.95–2.82)
Parity
 Nulliparous 58 (10.2) 25 (11.1) 1.02 (0.59–1.75) 9 (5.66) 0.71 (0.32–1.57)
 1 to 2 children 176 (30.8) 74 (32.9) 1.00 39 (24.5) 1.00
 ≥ 3 children 337 (59.0) 126 (56.0) 0.87 (0.61–1.24) 111 (69.8) 1.68 (1.10–2.55)
 Per birth (excludes nulliparous) 0.99 (0.91–1.08) 1.07 (0.98–1.18)
Age at first full-term pregnancy, y
 < 21 201 (39.2) 77 (38.5) 1.00 68 (45.6) 1.00
 21–24 133 (25.9) 55 (27.5) 1.08 (0.72–1.63) 42 (28.2) 0.90 (0.58–1.41)
 ≥ 25 179 (34.9) 68 (34.0) 0.99 (0.68–1.46) 39 (26.2) 0.61 (0.39–0.95)
 Per 5 y 1.00 (0.97–1.03) 0.95 (0.92–0.99)
Time since last full-term pregnancyb, y
 > 10 159 (64.4) 53 (57.0) 1.00 48 (60.0) 1.00
 ≤ 10 88 (35.6) 40 (43.0) 1.83 (0.96–3.48) 32 (40.0) 0.76 (0.38–1.52)
 Per 5 y 0.97 (0.78–1.21) 0.99 (0.78–1.26)
Lifetime duration of breastfeedingc, mo
 Never 134 (26.1) 58 (29.0) 1.00 23 (15.3) 1.00
 Up to 12 188 (36.7) 63 (31.5) 0.77 (0.50–1.18) 52 (34.7) 1.44 (0.83–2.49)
 > 12 191 (37.2) 79 (39.5) 0.97 (0.63–1.50) 75 (50.0) 2.14 (1.24–3.68)
 Per 6 mo 1.03 (0.99–1.06) 1.04 (1.01–1.08)
Breastfeeding duration per birthc, mo
 Never 134 (26.1) 58 (29.0) 1.00 23 (15.3) 1.00
 > 0 to 5 206 (40.2) 66 (33.0) 0.74 (0.49–1.13) 60 (40.0) 1.52 (0.89–2.60)
 > 5 173 (33.7) 76 (38.0) 1.03 (0.67–1.59) 67 (44.7) 2.07 (1.20–3.58)
 Per 6 mo 1.06 (0.91–1.24) 1.20 (1.03–1.41)
Time from menarche to first pregnancy, y
 < 8 179 (34.9) 71 (35.5) 1.00 69 (46.6) 1.00
 8–12 172 (33.5) 68 (34.0) 1.00 (0.67–1.48) 49 (33.1) 0.75 (0.49–1.15)
 ≥ 13 162 (31.6) 61 (30.5) 0.95 (0.63–1.42) 30 (20.3) 0.47 (0.29–0.77)
 Per 10 y 0.99 (0.85–1.14) 0.78 (0.65–0.93)
Duration of menstruationd, y
 7.6–27.35 172 (32.4) 59 (28.8) 1.00 64 (42.4) 1.00
 27.4–33.45 174 (32.8) 62 (30.2) 1.04 (0.68–1.59) 60 (39.7) 0.99 (0.65–1.53)
 33.5–50.5 185 (34.8) 84 (41.0) 1.33 (0.87–2.03) 27 (17.9) 0.43 (0.25–0.74)
 Per 5 y 1.09 (0.95–1.24) 0.79 (0.69–0.91)
Duration of menstruatione, y
 0–25.23 150 (31.5) 56 (30.8) 1.00 58 (40.9) 1.00
 25.25–31.75 160 (33.6) 55 (30.2) 0.92 (0.60–1.43) 57 (40.1) 0.96 (0.62–1.49)
 31.85–50.5 166 (34.9) 71 (39.0) 1.15 (0.75–1.78) 27 (19.0) 0.47 (0.28–0.79)
 Per 5 y 1.04 (0.92–1.18) 0.82 (0.72–0.93)
Age at menopause, y
 < 50 164 (57.1) 68 (58.6) 1.00 48 (68.6) 1.00
 ≥ 50 123 (42.9) 48 (41.4) 0.97 (0.62–1.52) 22 (31.4) 0.59 (0.33–1.04)
 Per 5 y 1.07 (0.90–1.27) 0.82 (0.67–1.01)
Hormone replacement therapy
 Never 490 (86.9) 192 (85.7) 1.00 142 (89.3) 1.00
 Ever 74 (13.1) 32 (14.3) 1.09 (0.69–1.72) 17 (10.7) 0.99 (0.56–1.77)
Hormone contraceptive use
 Never 244 (42.8) 102 (45.3) 1.00 78 (49.1) 1.00
 Ever 326 (57.2) 123 (54.7) 0.91 (0.66–1.26) 81 (50.9) 0.70 (0.49–1.01)

Abbreviations: CI, confidence interval; HER2, human epidermal growth factor receptor 2; OR, odds ratio; TNBC, triple negative breast cancer.

a

Adjusted for age at diagnosis (continuous) and country (U.S. vs. Mexico).

b

Among pre-menopausal women only.

c

Excludes nulliparous women.

d

Tertile categories; duration accounts for pregnancy. Excludes 62 women never having a regular period and 13 women with unknown age at menopause or menopausal status.

e

Tertile categories; duration accounts for pregnancy and breastfeeding. Excludes 62 women never having a regular period, 13 women with unknown age at menopause/menopausal status, and 99 women with unknown lifetime duration breastfeeding.