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Table 5 Association of progesterone receptor status and reproductive and family history variables

From: Effect of reproductive factors on stage, grade and hormone receptor status in early-onset breast cancer

Reproductive and family history characteristics PgR-positive or borderline tumors (n = 91) PgR-negative tumors (n = 85) ORa 95% CI P
Age at menarche (years)b
   <12 14 (15.6) 21 (25.3) 1.0 (ref)   
   ≥ 12 76 (84.4) 62 (74.7) 0.6 0.3–1.2 0.14
Age at first full-term pregnancy
   No full-term pregnancies 27 (29.7) 25 (29.4) 1.0 (ref)   
   <20 10 (11.0) 15 (17.6) 1.6 0.6–4.4 0.37
   20–24 25 (27.5) 20 (23.5) 0.8 0.4–2.0 0.71
   25–29 19 (20.9) 18 (21.2) 1.1 0.5–2.6 0.82
   30–34 10 (11.0) 7 (8.2) 0.9 0.3–2.9 0.88
   Trend      0.65
Total live births
   0 27 (29.7) 25 (29.4) 1.0 (ref)   
   1–2 53 (58.2) 50 (58.8) 1.1 0.5–2.1 0.87
   3 or more 11 (12.1) 10 (11.8) 1.0 0.3–2.9 1.00
   Trend      0.95
Total miscarriages (gravid women)
   0 54 (76.1) 45 (69.2) 1.0 (ref)   
   1 or more 17 (23.9) 20 (30.8) 1.4 0.7–3.0 0.38
Total induced abortions (gravid women)
   0 46 (64.8) 44 (67.7) 1.0 (ref)   
   1 or more 25 (35.2) 21 (32.3) 0.8 0.4–1.7 0.65
Breastfeeding (parous women)
   Never 14 (21.9) 25 (41.7) 1.0 (ref)   
   Ever 50 (78.1) 35 (58.3) 0.4 0.2–0.8 0.02
Months between last full-term pregnancy and diagnosis
   No full-term pregnancy 27 (29.7) 25 (29.4) 1.0 (ref)   
   0–23 17 (18.7) 16 (18.8) 1.0 0.4–2.5 0.95
   ≥ 24 47 (51.6) 44 (51.8) 1.1 0.5–2.2 0.87
   Trend      0.87
Oral contraceptive use
   Never 19 (20.9) 10 (11.8) 1.0 (ref)   
   Ever 72 (79.1) 75 (88.2) 2.0 0.8–4.6 0.11
Total months of oral contraceptive usec
   None 19 (21.3) 10 (12.2) 1.0 (ref)   
   1–35 23 (25.8) 23 (28.0) 1.6 0.6–3.9 0.33
   36–83 14 (15.7) 20 (24.4) 2.3 0.9–6.1 0.10
   84 or more 33 (37.1) 29 (35.4) 1.5 0.6–3.5 0.38
   Trend      0.34
Family history of breast or ovarian cancerd
   No family history 71 (78.9) 70 (83.3) 1.0 (ref)   
   Mother or sister 19 (21.1) 14 (16.7) 0.8 0.4–1.8 0.58
  1. aAnalyses adjusted for age at diagnosis and education (higher of self or spouse).
  2. bThree records missing age at menarche. cFive records missing total months of oral contraceptive use. dTwo records were excluded because proband reported being adopted. CI, confidence interval; PgR, progesterone receptor; OR, odds ratio.