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Table 2 Risk associations for ER+ and ER- tumors, the EPIC study and the WHI studya

From: Risk prediction for estrogen receptor-specific breast cancers in two large prospective cohorts

Risk factors

EPIC study

WHI study

ER+, n = 7210

HR (95% CI)

ER-, n = 1598

HR (95% CI)

ER+, n = 2276

HR (95% CI)

ER-, n = 421

HR (95% CI)

Menopausal status:

 postmenopausalb vs premenopausal

0.66 (0.60–0.74)

–

Age at menopause, years:

 45.1–50.0 vs ≤ 45.0

1.16 (1.06–1.28)

1.16 (1.05–1.29)

 50.1–55.0 vs ≤ 45.0

1.25 (1.13–1.38)

1.41 (1.27–1.56)

 > 55.0 vs ≤ 45.0

1.41 (1.21–1.63)e

1.40 (1.20–1.62)

Breastfeeding, months:

 0.1–6 vs 0

1.01 (0.95–1.08)

1.04 (0.94–1.14)

 6.1–12 vs 0

0.96 (0.88–1.04)

1.04 (0.91–1.18)

 > 12 vs 0

1.01 (0.93–1.11)

1.07 (0.95–1.20)

Age at menarche, years:

 12 vs ≤ 11

1.06 (0.98–1.14)

0.89 (0.80–0.99)

 13 vs ≤ 11

1.00 (0.93–1.07)

0.82 (0.74–0.91)

 14 vs ≤ 11

0.97 (0.91–1.05)

0.86 (0.75–0.98)

 ≥ 15 vs ≤ 11

0.85 (0.79–0.92)

0.78 (0.67–0.91)

HRT use, years:

 0.1–1.0 vs 0

1.17 (1.09–1.26)

1.01 (0.86–1.19)

 1.1–2.0 vs 0

1.27 (1.15–1.40)

1.17 (0.97–1.40)

 2.1–3.0 vs 0

1.39 (1.24–1.56)

1.37 (1.13–1.65)

 > 3.0 vs 0

1.55 (1.44–1.66)e

1.53 (1.39–1.67)e

BMI, kg/m2:

 25.0–29.9 vs < 25.0

0.99 (0.92–1.07)

1.02 (0.93–1.12)

 30.0–34.9 vs < 25.0

0.97 (0.85–1.10)

1.14 (1.02–1.28)

 ≥ 35.0 vs < 25.0

1.12 (0.92–1.36)

1.23 (1.07–1.41)

BMI* menopausec:

 1 vs 0

1.11 (1.01–1.23)

–

 2 vs 0

1.26 (1.07–1.47)

–

 3 vs 0

1.17 (0.91–1.50)

–

Alcohol intake, drinks per day:

 < 1.0 vs 0

1.00 (0.94–1.07)

1.08 (0.91–1.29)

 1.0–1.9 vs 0

1.14 (1.05–1.24)

1.20 (0.98–1.47)

 ≥ 2.0 vs 0

1.22 (1.12–1.33)

1.26 (1.01–1.59)

FTPd:

 Yes vs no

0.81 (0.71–0.91)

0.97 (0.76–1.24)

0.85 (0.67–1.08)

0.65 (0.37–1.14)

Number of FTP:

 2 vs 1

0.99 (0.92–1.06)

1.05 (0.90–1.22)

1.14 (0.97–1.34)

1.15 (0.78–1.70)

 ≥ 3 vs 1

0.87 (0.80–0.95)

0.95 (0.81–1.13)

0.99 (0.84–1.17)

0.96 (0.65–1.41)

Age at 1st FTP, years:

 20.1–25.0 vs ≤ 20.0

1.05 (0.97–1.14)

1.04 (0.89–1.23)

1.03 (0.89–1.20)

1.37 (0.97–1.95)

 25.1–30.0 vs ≤ 20.0

1.20 (1.10–1.31)

0.93 (0.78–1.12)

1.14 (0.97–1.33)

1.34 (0.92–1.96)

 30.1–35.0 vs ≤ 20.0

1.32 (1.18–1.48)

0.96 (0.75–1.23)

1.59 (1.31–1.94)

1.01 (0.58–1.75)

 > 3.05 vs ≤ 20.0

1.46 (1.24–1.73)e

0.91 (0.59–1.38)

1.56 (1.16–2.09)

1.10 (0.48–2.53)

Height, per 10-cm increment

1.19 (1.15–1.24)

1.06 (0.98–1.16)

1.14 (1.06–1.22)

1.04 (0.89–1.22)

  1. BMI body mass index, CI confidence interval, EPIC European Prospective Investigation into Cancer and Nutrition, ER estrogen receptor, FTP full-term pregnancy, HR hazard ratio, HRT hormone replacement therapy, WHI Women’s Health Initiative
  2. aHeterogeneous risk associations among the EPIC women were examined using the likelihood ratio test. The resulting heterogeneous risk factor profiles were applied to the WHI women
  3. bAge at menopause ≤ 45 years
  4. c0: premenopausal or postmenopausal and BMI < 25 kg/m2; 1: postmenopausal and BMI 25.0–29.9 kg/m2; 2: postmenopausal and BMI 30.0–34.9 kg/m2; 3: postmenopausal and BMI ≥ 35 kg/m2. Among postmenopausal women, the HRs (95% CIs) for BMI from low to high categories were 1.11 (1.04–1.18), 1.21 (1.10–1.34), and 1.30 (1.11–1.53)
  5. dThe number of FTP = 1 and age at first FTP ≤ 20 years.
  6. eptrend < 0.001
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Breast Cancer Research

ISSN: 1465-542X

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