Table 1:

Subject characteristics, hormone measures, and IGF-1/IGFBP-3 molar ratio

Variable	N	All women (N=316)	N	Parous women (N=44)	N	Nulliparous women (N=272)
Age at donation (years)	316	25 (21, 33)	44	35 (32, 40)	272	23 (21, 30)
Ethnicity (Hispanic/Latino)	315	9 (2.9%)	44	1 (2.3%)	271	8 (3.0%)
Race	316		44		272
Caucasian		282 (89.2%)		37 (84.1%)		245 (90.1%)
African American		34 (10.8%)		7 (15.9%)		27 (9.9%)
BMI	316	24.9 (22.0, 29.7)	44	27.4 (22.7, 33.3)	272	24.5 (22.0, 29.1)
Percent fat	316	60 (40, 90)	44	70 (50, 90)	272	60 (40, 80)
Current smoking	316	13 (4.1%)	44	0 (0.0%)	272	13 (4.8%)
Current drinking	315	233 (74.0%)	44	30 (68.2%)	271	203 (74.9%)
Age at first period (years)	316	12.5 (12, 13)	44	13 (12, 13)	272	12 (12, 13)
Number of live births	44		44		N/A	N/A
1		17 (38.6%)		17 (38.6%)
2		19 (43.2%)		19 (43.2%)
3		7 (15.9%)		7 (15.9%)
4		0 (0.0%)		0 (0.0%)
5		1 (2.3%)		1 (2.3%)
Time since last birth (years)	44	3.7 (2.4, 7.0)	44	3.7 (2.4, 7.0)	N/A	N/A
Age at first birth (years)	44	29 (26, 32)	44	29 (26, 32)	N/A	N/A
History of breastfeeding	44	37 (84.1%)	44	37 (84.1%)	N/A	N/A
Total months breastfeeding	37	12 (6, 19)	37	12 (6, 19)	N/A	N/A
Total months breastfeeding (with no breastfeeding considered to be 0 months)	44	7 (3, 18)	44	7 (3, 18)	N/A	N/A
Relative with breast/ovarian cancer	298	150 (50.3%)	41	26 (63.4%)	257	124 (48.2%)
Estrogen	174	36 (10, 61)	22	54 (45, 64)	152	30 (9, 60)
Progesterone	176	0.40 (0.20, 0.70)	22	0.25 (0.20, 0.40)	154	0.40 (0.20, 0.70)
Prolactin	176	7.95 (6.10, 10.45)	22	7.05 (5.80, 10.40)	154	8.10 (6.20, 10.50)
SHBG	149	91 (47, 167)	20	80 (38, 115)	129	93 (52, 191)
Testosterone	172	16 (11, 27)	21	11 (7, 20)	151	17 (12, 29)
IGF-1	205	173 (135, 222)	37	150 (126, 180)	168	182 (140, 230)
IGF-1/IGFBP-3 molar ratio	205	0.12 (0.10, 0.16)	37	0.12 (0.10, 0.14)	168	0.13 (0.10, 0.16)

The sample median (Q1, Q3) is given for continuous variables.