Table 1.

Demographic characteristics of the study population

Controls (n = 877)Ductal cases (n = 891)Lobular cases (n = 1,036)
CharacteristicN (%)N (%)N (%)
Age at reference date
 55–59252 (28.7)259 (29.1)306 (29.5)
 60–64230 (26.2)245 (27.5)294 (28.4)
 65–69222 (25.3)211 (23.7)241 (23.3)
 70–74173 (19.7)176 (19.8)195 (18.8)
Race/ethnicity
 Non-Hispanic White778 (88.9)804 (90.4)960 (92.8)
 African American27 (3.1)22 (2.5)14 (1.4)
 Asian/Pacific Islander17 (1.9)35 (3.9)21 (2.0)
 Native American24 (2.7)16 (1.8)20 (1.9)
 Hispanic White29 (3.3)12 (1.3)20 (1.9)
 Missing221
Education
 Less than high school39 (4.5)46 (5.2)62 (6.0)
 High school graduate207 (23.6)207 (23.3)365 (35.2)
 Some college343 (39.2)331 (37.2)221 (21.3)
 College degree or higher287 (32.8)306 (34.4)388 (37.5)
 Missing110
Annual household income
 <$20,00082 (10.7)102 (12.9)100 (11.0)
 $20,000–$34,999138 (18.0)129 (16.3)173 (19.1)
 $35,000–$69,999285 (37.1)273 (34.6)294 (32.5)
 $70,000–$89,99988 (11.5)102 (12.9)132 (14.6)
 ≥ $90,000175 (22.8)184 (23.3)207 (22.8)
 Missing109101130
Alcohol use
 None441 (50.6)419 (47.4)480 (46.6)
 <1 drink per day299 (34.3)312 (35.3)345 (33.5)
 ≥1 drink per day132 (15.1)153 (17.3)205 (19.9)
 Missing576
Smoking status
 Never440 (50.2)445 (50.0)495 (47.8)
 Former348 (39.7)342 (38.4)416 (40.2)
 Current88 (10.0)103 (11.6)125 (12.1)
 Missing110
Body mass index, kg/m2
 <25264 (30.4)285 (32.0)367 (35.5)
 25–29.9300 (34.5)283 (31.8)342 (33.1)
 ≥30305 (35.1)322 (36.2)324 (31.4)
 Missing813
History of high cholesterol
 No602 (68.8)604 (67.9)713 (69.0)
 Yes273 (31.2)286 (32.1)320 (31.0)
 Missing213
History of heart disease
 No385 (44.0)406 (45.7)471 (45.6)
 Yes490 (56.0)482 (54.3)563 (54.4)
 Missing232
First-degree family history of breast cancer
 No697 (82.2)654 (76.7)771 (76.8)
 Yes151 (17.8)199 (23.3)233 (23.2)
 Missing293832
Mammography screening history
 Less than annual394 (45.1)409 (46.0)490 (47.6)
 Annual only469 (53.7)462 (52.0)521 (50.6)
 More than annual11 (1.3)18 (2.0)19 (1.9)
 Missing326
Hormone therapy use
 Never249 (28.4)322 (36.1)261 (25.2)
 Former310 (35.3)242 (27.2)256 (24.7)
 Current estrogen only202 (23.0)162 (18.2)219 (21.1)
 Current estrogen + progestin116 (13.2)165 (18.5)300 (29.0)