Table 1 Comparisons of characteristics between parous and nulliparous women

Age of donation (years)

180

35 (22, 45)

545

25 (18, 45)

 < 0.001

Ethnicity (Hispanic/Latino)

180

13 (7.2%)

544

39 (7.2%)

1.00

Race

180

545

0.10

 Caucasian

149 (82.8%)

479 (87.9%)

 African American

31 (17.2%)

66 (12.1%)

BMI

180

27.0 (14.3, 62.9)

545

25.4 (13.3, 63.2)

0.062

Current smoking

166

5 (3.0%)

530

31 (5.8%)

0.17

Current drinking

179

125 (69.8%)

542

394 (72.7%)

0.50

Age at first period (years)

180

12.5 (8, 19)

545

12 (8, 18)

0.44

Menstrual status

180

544

0.82

 Pre-menopausal

173 (96.1%)

525 (96.5%)

 Post-menopausal

4 (2.2%)

11 (2.0%)

 Uterine ablation

3 (1.7%)

8 (1.5%)

Number of live births

180

N/A

N/A

N/A

 1

61 (33.9%)

 2

83 (46.1%)

 3

31 (17.2%)

 4

4 (2.2%)

 5

1 (0.6%)

Time since last birth (years)

180

4.0 (0.1, 11.0)

N/A

N/A

N/A

Age at first birth (years)

180

28 (16, 41)

N/A

N/A

N/A

History of breastfeeding

180

156 (86.7%)

N/A

N/A

N/A

 Total months breastfeeding

156

9 (1, 90)

N/A

N/A

N/A

Total months breastfeeding (with no breastfeeding considered to be 0 months)

180

6 (0, 90)

N/A

N/A

N/A

Relative with breast/ovarian cancer

168

104 (61.9%)

511

252 (49.3%)

0.006