Table 1.

Distributions of demographic characteristics and established breast cancer risk factors among controls and luminal, HER2-overexpressing, and triple-negative cases

Controls (n = 1,447), n (%)Cases
Luminal (ER+; n = 1,008), n (%)HER2-overexpressing (ER−/PR−/HER2+; n = 39) n (%)Triple-negative (ER−/PR−/HER2−; n = 77), n (%)
Age, y
    55-59131 (9)120 (12)5 (13)16 (21)
    60-64119 (8)106 (11)7 (18)12 (16)
    65-69440 (30)275 (27)10 (26)27 (35)
    70-74470 (32)332 (33)9 (23)12 (16)
    75-79287 (20)175 (17)8 (21)10 (13)
    Mean69.368.667.666.0
Race/ethnicity
    Non-Hispanic White1,323 (91)945 (94)32 (82)71 (92)
    African American42 (3)16 (2)2 (5)3 (4)
    Asian/Pacific Islander38 (3)29 (3)3 (8)1 (1)
    Hispanic White25 (2)8 (1)2 (5)1 (1)
    Other19 (1)10 (1)0 (0)1 (1)
Education
    High school or less682 (47)441 (44)18 (46)33 (43)
    Some college460 (32)332 (33)17 (44)28 (36)
    College graduate304 (21)235 (23)4 (10)16 (21)
First-degree family history of breast cancer
    No1,131 (83)727 (77)33 (85)61 (87)
    Yes226 (17)219 (23)6 (15)9 (13)
    Missing903807
Hormone therapy use
    Never use539 (37)340 (34)10 (27)32 (42)
    Former use247 (17)165 (17)11 (30)13 (17)
    Current use of unopposed estrogen450 (31)246 (25)10 (27)21 (27)
    Current use of estrogen + progestin207 (14)246 (25)6 (16)11 (14)
    Missing41120
Parity
    0125 (9)113 (11)3 (8)7 (9)
    1114 (8)93 (9)4 (10)9 (12)
    2346 (24)267 (26)16 (41)21 (27)
    3389 (27)256 (25)4 (10)18 (23)
    ≥4473 (33)279 (28)12 (31)22 (29)
Age at first live birth, y
    <20268 (20)176 (20)4 (11)14 (20)
    20-24640 (49)427 (48)24 (67)33 (47)
    25-29299 (23)197 (22)6 (17)19 (27)
    ≥30112 (8)92 (10)2 (6)4 (6)