Table 1.

Demographic and clinical factors by case–control status among women with carcinoma in situ of the breast

Study participants, N (%)
First-degree family history of breast cancer
CharacteristicsNo (n = 1,094)Yes (n = 439)
Age at first breast cancer diagnosis
 <50367 (33.6)164 (37.4)
 50–59386 (35.3)144 (32.8)
 60–69225 (20.6)92 (21.0)
 70–79116 (10.6)39 (8.9)
Year of first breast cancer diagnosis
 1995–1997231 (21.1)103 (23.5)
 1998–2000247 (22.6)112 (25.5)
 2001–2004311 (28.4)105 (23.9)
 2005–2013305 (27.9)119 (27.1)
Race/ethnicity
 Non-Hispanic white976 (89.2)403 (91.8)
 Hispanic white22 (2.0)10 (2.3)
 Black22 (2.0)5 (1.1)
 Asian/Pacific Islander57 (5.2)16 (3.6)
 Native American16 (1.5)5 (1.1)
 Unknown10
Body mass index at first breast cancer diagnosis
 <25499 (47.3)197 (46.9)
 25–<30309 (29.3)128 (30.5)
 ≥30247 (23.4)95 (22.6)
 Unknown3919
Body mass index at reference
 <25445 (43.8)174 (42.2)
 25-<30308 (30.3)144 (35.0)
 ≥30263 (25.9)94 (22.8)
 Unknown7827
Smoking status at first breast cancer diagnosis
 Never smoker594 (56.0)243 (57.2)
 Former smoker355 (33.5)137 (32.2)
 Current smoker111 (10.5)45 (10.6)
 Unknown3414
Grade of first tumor
 1 – well differentiated30 (3.8)10 (3.3)
 2 – moderately differentiated227 (28.6)92 (30.0)
 3 – poorly differentiated252 (31.7)88 (28.7)
 4 – undifferentiated285 (35.9)117 (38.1)
 Unknown300132
Radiation treatment for first breast cancer
 Yes529 (48.4)192 (43.7)
 No565 (51.7)247 (56.3)
Surgery for first breast cancer
 Biopsy only36 (3.3)20 (4.6)
 Lumpectomy without nodal dissection751 (68.7)303 (69.0)
 Lumpectomy with sentinal node biopsy55 (5.0)20 (4.6)
 Lumpectomy with nodal dissection45 (4.1)9 (2.1)
 Mastectomy207 (18.9)87 (19.8)
Laterality of second breast cancer
 Ipsilateral154 (42.2)85 (48.9)
 Contralateral210 (57.5)86 (49.4)
 Bilateral1 (0.3)3 (1.7)
Menopausal status at first breast cancer diagnosis
 Pre/Peri-menopausal417 (39.2)183 (43.5)
 Postmenopausal646 (60.8)238 (56.5)
 Unknown3118
Menopausal status at reference
 Pre/Peri-menopausal191 (18.2)91 (21.9)
 Postmenopausal856 (81.8)324 (78.1)
 Unknown4724