Table 1.

Characteristics of subjects in discovery and validation phases

 Discovery cohortValidation cohortDiscovery vs. validation P for differencea
Parous (n = 37) Mean (SD) or N [%]Nulliparous (n = 18) Mean (SD) or N [%]P for differenceaParous (n = 30) Mean (SD) or N [%]Nulliparous (n = 22) Mean (SD) or N [%]P for differenceaParousNulliparous
Age at visit, y60.1 (4.7)60.8 (4.8)0.5758.9 (5.2)59.5 (5.8)0.790.410.40
Age at menarche, y13.2 (2.0)13.1 (1.6)0.8013.2 (1.6)13.1 (1.4)0.870.540.61
Age at menopause, y47.5 (7.6)49.2 (7.3)0.4648.7 (4.5)49.0 (4.8)0.950.800.61
BMI, kg/m225.2 (4.1)27.5 (6.3)0.2224.1 (2.4)24.4 (3.3)0.900.360.13
OC start age, y22.4 (5.8)19.5 (4.2)0.0722.0 (6.5)20.2 (3.3)0.750.600.43
OC duration, y6.0 (6.9)5.7 (5.3)0.756.4 (7.2)10.1 (7.2)0.120.710.10
HRT age, y49.3 (4.8)45.6 (9.6)0.6049.1 (6.5)49.2 (4.1)0.980.870.64
HRT duration, y5.75 (4.5)10.4 (7.1)0.107.2 (5.0)6.5 (4.5) 8.0 (4.0)0.710.340.75
OC use: no yes5 [13%] 32 [87%]3 [17%] 15 [83%]1.007 [23%] 23 [77%]10 [45%] 12 [55%]0.140.350.09
HRT use: no yes16 [43%] 21 [57%]10 [56%] 8 [44%]0.5712 [40%] 18 [60%]9 [41%] 13 [59%]1.000.810.53
Hysterectomy: no yes29 [78%] 8 [22%]13 [72%] 5 [28%]0.7426 [87%] 4 [13%]18 [82%] 4 [18%]0.710.530.71
Smoking: never former current11 [30%] 17 [46%] 9 [24%]5 [28%] 11 [61%] 2 [11%]0.4814 [47%] 11 [37%] 5 [16%]9 [41%] 11 [50%] 2 [9%]0.590.350.73
Family history of breast cancer no yes31 [84%] 6 [16%]18 [100%] 0 [0%]0.1628 [93%] 2 [7%]19 [86%] 3 [14%]0.640.280.24
Pregnancies, n 1 2 >26 [16%] 5 [14%] 26 [70%]3 [10%] 10 [33%] 17 [57%]0.16
FTP, n 0 1 2 >20 9 [24%] 15 [41%] 13 [35%]0 3 [10%] 15 [50%] 12 [40%]0.34
Age at first pregnancy, mean (SD) categories, n (%) <25 25–29 ≥3023.0 (3.9) 23 (62%) 11 (30%) 3 (8%)23.4 (4.6) 18 (60%) 8 (27%) 4 (13%)1.00
Age at first FTP, mean (SD)24.1 (4.5)23.9 (4.8)0.82
Breast feeding,%100%100%1.00
Breast feeding mean (SD) duration, weeks52.2 (50.0)63.2 (72.3)0.88
  • aBased on Wilcoxon Rank Sum test for continuous variables and Fisher's exact test for categorical variables.