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Table 4 Adjusted odds ratios (OR) and 95% confidence intervals (CI) for association between breast cancer overall and subtypes of breast cancer, and the duration of estrogen and progestin therapy (EPT) by body mass index (BMI)

From: Parity, hormones and breast cancer subtypes - results from a large nested case-control study in a national screening program

OVERALL breast cancer
  BMI <25 BMI ≥25
Controls (n) Cases (n) OR* 95% CI Controls (n) Cases (n) OR 95% CI
Duration of EPT (years)
 Never used 6154 1056 1 Reference 6880 1402 1 Reference
  < =5 1740 316 1.20 (1.00, 1.44) 1812 420 1.13 (0.97, 1.32)
 >5 1623 495 1.96 (1.64, 2.34) 1615 456 1.31 (1.12, 1.54)
p-trend*    <0.0001     <0.0001  
p for interaction    0.001      
Luminal A-like breast cancer
 Duration of EPT (years)
  Never used 3424 550 1 Reference 3892 789 1 Reference
   < =5 959 176 1.36 (1.06, 1.74) 987 243 1.22 (0.99, 1.50)
  >5 896 293 2.29 (1.80, 2.91) 906 270 1.38 (1.12, 1.71)
   p-trend    <0.0001     0.002  
   p for interaction    0.001      
Luminal B-like HER2-negative breast cancer
 Duration of EPT (years)
  Never used 850 173 1 Reference 887 178 1 Reference
   < =5 257 57 1.13 (0.74, 1.71) 295 59 0.83 (0.54, 1.29)
  >5 243 71 1.22 (0.79, 1.88) 256 47 0.83 (0.51, 1.35)
   p-trend    0.34     0.37  
   p for interaction    0.03      
Luminal B-like HER2-positive breast cancer
 Duration of EPT (years)
  Never used 450 81 1 Reference 544 113 1 Reference
   < =5 137 16 0.85 (0.40, 1.81) 144 29 0.82 (0.45, 1.49)
  >5 127 28 1.56 (0.67, 3.60) 130 43 1.56 (0.87, 2.78)
   p-trend    0.44     0.24  
   p for interaction    0.52      
HER2-positive breast cancer
 Duration of EPT (years)
  Never used 269 54 1 Reference 296 56 1 Reference
   < =5 80 16 1.14 (0.44, 2.95) 77 14 1.38 (0.62, 3.08)
  >5 49 13 1.53 (0.57, 4.05) 57 17 1.28 (0.56, 2.93)
   p-trend    0.41     0.43  
   p for interaction    0.89      
Triple-negative breast cancer
 Duration of EPT (years)
  Never used 457 94 1 Reference 522 101 1 Reference
   < =5 123 20 0.96 (0.45, 2.04) 110 34 1.40 (0.79, 2.47)
  >5 113 25 1.27 (0.56, 2.86) 100 27 1.34 (0.71, 2.54)
   p-trend    0.63     0.25  
   p for interaction    0.09      
  1. *p for trend and ORs mutually adjusted for age (50–54, 55–59, 60–64, 65–70 years at screening), BMI (≤22, 23–25, 26–28, >28 at screening), age at menarche (9–12, 13, 14, 15–18), education (no education/primary school, high school, bachelor’s or master’s degree), number of pregnancies (0, 1, 2, 3, ≥4), menopausal status (premenopausal, perimenopausal, postmenopausal). HER2 human epidermal growth factor receptor 2