Table 1.

Demographic and health characteristics of women at diagnosis by breast cancer subtype

Luminal ALuminal BBasal-likeHER2-enrichedTotal
(N = 615)(N = 42)(N = 210)(N = 67)(N = 934)
N (%)N (%)N (%)N (%)N (%)
Year of diagnosis
 1988–198990 (14.6)4 (9.5)34 (16.2)9 (13.4)137 (14.7)
 1990–1991124 (20.2)12 (28.6)39 (18.6)10 (14.9)185 (19.8)
 1992–1993191 (31.1)16 (38.1)68 (32.4)18 (26.9)293 (31.4)
 1994–1995210 (34.1)10 (23.8)69 (32.9)30 (44.8)319 (34.2)
  P = 0.48
Age at diagnosis (y)
 <50163 (26.5)24 (57.1)81 (38.6)26 (38.8)294 (31.5)
 50–59120 (19.5)6 (14.3)54 (25.7)18 (26.9)198 (21.2)
 60–69187 (30.4)11 (26.2)47 (22.4)18 (26.9)263 (28.2)
 >70145 (23.6)1 (2.4)28 (13.3)5 (7.5)179 (19.2)
  P < 0.0001
Race
 White540 (87.8)32 (76.2)177 (84.3)53 (79.1)802 (85.9)
 Other75 (12.2)10 (23.8)33 (15.7)14 (20.9)132 (14.1)
  P = 0.044
Family history of breast cancera
 Yes110 (17.9)9 (21.4)33 (15.7)9 (13.4)161 (17.2)
 No416 (67.6)29 (69.0)148 (70.5)50 (74.6)643 (68.8)
 Unknown89 (14.5)4 (9.5)29 (13.8)8 (11.9)130 (13.9)
  P = 0.62
Menopausal status
 Pre170 (31.3)21 (52.5)81 (44.0)22 (37.9)294 (35.6)
 Post373 (68.7)19 (47.5)103 (56.0)36 (62.1)531 (64.4)
  P = 0.0017
BMI (kg/m2)
 <18.58 (1.3)1 (2.4)4 (1.9)2 (3.0)15 (1.6)
 18.5–24.9213 (34.6)14 (33.3)74 (35.2)15 (22.4)316 (33.8)
 25–29.9172 (28.0)14 (33.3)62 (29.5)28 (41.8)276 (29.6)
 ≥30140 (22.8)8 (19.0)43 (20.5)13 (19.4)204 (21.8)
 Unknown82 (13.3)5 (11.9)27 (12.9)9 (13.4)123 (13.2)
  P = 0.42
Smoking history
 Never284 (46.2)19 (45.2)107 (51.0)35 (52.2)445 (47.6)
 Smoker at diagnosis94 (15.3)8 (19.0)21 (10.0)7 (10.4)130 (13.9)
 Former smoker134 (21.8)8 (19.0)53 (25.2)14 (20.9)209 (22.4)
 Nonsmoker36 (5.9)4 (9.5)8 (3.8)4 (6.0)52 (5.6)
 Unknown67 (10.9)3 (7.1)21 (10.0)7 (10.4)98 (10.5)
  P = 0.43
Live births
 078 (12.7)7 (16.7)32 (15.2)11 (16.4)128 (13.7)
 ≥1464 (75.4)32 (76.2)148 (70.5)49 (73.1)693 (74.2)
 Unknown73 (11.9)3 (7.1)30 (14.3)7 (10.4)113 (12.1)
  P = 0.63

NOTE: P values based on χ2 test. Unknown data were excluded in calculation of P value. For variables with categories <5, P values are based on the Fisher exact test.

  • aHistory of breast cancer in first degree blood relative (mother, sister, or daughter).