Table 2: Reproductive characteristics and medical history of Black women aged 40-75 years in the WCHS, overall and by initial mode of breast cancer detection.

OverallScreening mammogramClinical breast examSelf-detectionP-value
(N = 1322)(n = 725)(n = 63)(n = 534)
N ()n()n()n()

Menopausal status<0.0001
 Premenopausal516 (39.0)203 (28.0)36 (57.1)277 (51.9)
 Postmenopausal806 (61.0)522 (72.0)27 (42.9)257 (48.1)
Age at menarche (years)0.324
 <12381 (28.8)212 (29.2)11 (17.5)158 (29.6)
 12-13618 (46.8)338 (46.6)32 (50.8)248 (46.4)
 >13323 (24.4)175 (24.1)20 (31.8)128 (24.0)
Parity0.428
 Nulliparous231 (17.5)117 (16.1)9 (14.3)105 (19.7)
 1-2 children679 (51.4)377 (52.0)31 (49.2)271 (50.8)
 ≥3 children412 (31.2)231 (31.9)23 (36.5)158 (29.6)
Age at first birth (years0.605
 <25687 (63.0)382 (62.8)30 (55.6)275 (64.1)
 25-30242 (22.2)130 (21.4)15 (27.8)97 (22.6)
 >30162 (14.9)96 (15.8)9 (16.7)57 (13.3)
History of 0.458
 No592 (54.5)336 (55.5)32 (59.3)224 (52.3)
 Yes495 (45.5)269 (44.5)22 (40.7)204 (47.7)
History of oral contraceptive use0.685
 No933 (70.6)505 (69.7)42 (66.7)386 (72.3)
 Yes388 (29.4)219 (30.2)21 (33.3)148 (27.7)
History of hormone therapy use<0.0001
 No1084 (82.0)556 (76.7)57 (90.5)471 (88.2)
 Yes231 (17.5)166 (22.9)6 (9.5)59 (11.1)
Family history of breast cancer0.733
 No1075 (81.3)584 (80.6)52 (82.5)439 (82.2)
 Yes247 (18.7)141 (19.5)11 (17.5)95 (17.8)
Body mass index (kg/m2)<0.001
 <25.0261 (19.7)105 (14.5)16 (25.4)140 (26.2)
 25.0-29.99389 (29.4)226 (31.2)17 (27.0)146 (27.3)
 30.0-34.99312 (23.6)189 (26.1)14 (22.2)109 (20.4)
 ≥35.0359 (27.2)204 (28.1)16 (25.4)139 (26.0)

Age at first birth and history of breastfeeding data are among parous women only.