Article Figures & Data
Tables
- Table 1.
Distribution of selected characteristics among controls, ductal cases, and lobular cases
Controls Ductal cases Lobular cases (n = 469) (n = 454) (n = 590) Characteristic n (%) n (%) n (%) Age, y 55–59 137 (29.2) 126 (27.8) 178 (30.2) 60–64 121 (25.8) 109 (24.0) 155 (26.3) 65–69 113 (24.1) 117 (25.8) 141 (23.9) 70–74 98 (20.9) 102 (22.5) 116 (19.7) Race/ethnicity Non-Hispanic White 423 (90.2) 406 (89.6) 546 (92.5) African American 8 (1.7) 10 (2.2) 9 (1.5) Asian/Pacific Islander 9 (1.9) 16 (3.5) 11 (1.9) Native American 10 (2.1) 11 (2.4) 11 (1.9) Hispanic White 19 (4.1) 10 (2.2) 13 (2.2) Missing 0 1 0 Education High school or less 150 (32.0) 154 (33.9) 188 (31.9) Some college 182 (38.8) 163 (35.9) 198 (33.6) College graduates 87 (18.6) 88 (19.4) 124 (21.0) Postgraduates 50 (10.7) 49 (10.8) 80 (13.6) Annual income <$20,000 38 (9.6) 54 (14.1) 62 (12.5) $20,000–34,999 76 (19.3) 72 (18.8) 106 (21.4) $35,000–69,999 159 (40.4) 136 (35.5) 160 (32.3) $70,000–89,999 47 (11.9) 44 (11.5) 78 (15.7) ≥$90,000 74 (18.8) 77 (20.1) 90 (18.1) Missing 75 71 94 BMI at 30 years of age (kg/m2) <25.0 378 (82.0) 369 (81.8) 504 (86.7) 25.0–29.9 66 (14.3) 68 (15.1) 58 (10.0) ≥30.0 17 (3.7) 14 (3.1) 19 (3.3) Missing 8 3 9 BMI 1 month before reference date (kg/m2) <25.0 146 (31.2) 158 (34.8) 212 (36.1) 25.0–29.9 163 (34.8) 144 (31.7) 195 (33.2) ≥30 159 (34.0) 152 (33.5) 180 (30.7) Missing 1 0 3 Menopausal hormone therapy use Never 118 (25.3) 141 (31.2) 125 (21.2) Former 107 (23.0) 70 (15.5) 81 (13.8) Current estrogen only 146 (31.3) 110 (24.3) 142 (24.1) Current estrogen + progestin 95 (20.4) 131 (29.0) 241 (40.9) Missing 3 2 1 First-degree family history of breast cancer No 380 (84.3) 334 (77.9) 440 (76.5) Yes 71 (15.7) 95 (22.1) 135 (23.5) Missing 18 25 15 Had a mammogram within the past 2 years No 51 (10.9) 37 (8.1) 44 (7.5) Yes 418 (89.1) 417 (91.9) 546 (92.5) Menopausal status Natural 266 (58.0) 302 (67.7) 391 (68.2) Induceda 68 (14.8) 49 (11.0) 71 (12.4) Simple hysterectomy 125 (27.2) 95 (21.3) 111 (19.4) Missing 10 8 17 Parous No 36 (7.7) 60 (13.2) 81 (13.7) Yes 433 (92.3) 394 (86.8) 509 (86.3) -
↵aWomen who had bilateral oophorectomy were classified as having an induced menopause.
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- Table 2.
Associations between bra-wearing characteristics and breast cancer risk
Controls (n = 469) Ductal cases (n = 454) Lobular cases (n = 590) Bra-wearing characteristic n (%) n (%) OR (95% CI) n (%) OR (95% CI) Lifetime average hours/day wore a bra, quartiles ≤10.0 112 (25.1) 117 (27.1) Ref 152 (27.3) Ref 10.1–11.5 113 (25.3) 99 (22.9) 0.9 (0.6–1.3) 115 (20.6) 0.7 (0.5–1.0) 11.6–13.9 107 (24.0) 117 (27.1) 1.1 (0.7–1.6) 151 (27.1) 0.9 (0.7–1.4) ≥14 114 (25.6) 99 (22.9) 0.9 (0.6–1.3) 139 (25.0) 0.8 (0.6–1.2) P for trend 0.801 0.609 Current average hours/day wore a bra, quartiles ≤10.0 131 (29.5) 116 (26.9) Ref 165 (29.6) Ref 10.1–12.0 123 (27.5) 113 (26.2) 1.1 (0.8–1.6) 136 (24.4) 0.8 (0.6–1.2) 12.1–15.9 79 (17.7) 99 (22.9) 1.6 (1.0–2.3) 118 (21.2) 1.1 (0.7–1.6) ≥16 113 (25.3) 104 (24.1) 1.2 (0.8–1.8) 138 (24.8) 0.9 (0.6–1.3) P for trend 0.207 0.855 Ever regularly wore a bra with an underwire No 251 (56.4) 233 (54.1) Ref 331 (59.6) Ref Yes 194 (43.6) 198 (45.9) 1.2 (0.9–1.6) 224 (40.4) 0.8 (0.6–1.1) Currently wore a bra with an underwire No 283 (63.6) 273 (63.3) Ref 365 (65.8) Ref Yes 162 (36.4) 158 (36.7) 1.0 (0.8–1.4) 190 (34.2) 0.9 (0.7–1.1) Current average hours/day wore a bra without underwire, quartiles ≤10.0 96 (33.9) 87 (31.9) Ref 128 (35.1) Ref 10.1–12.0 87 (30.7) 80 (29.3) 1.1 (0.7–1.7) 97 (26.6) 0.8 (0.5–1.2) 12.1–15.9 41 (14.5) 51 (18.7) 1.6 (0.9–2.7) 70 (19.2) 1.1 (0.7–1.9) ≥16 59 (20.8) 55 (20.1) 1.2 (0.7–2.1) 70 (19.2) 0.8 (0.5–1.3) P for trend 0.281 0.713 Current average hours/day wore a bra with an underwire, quartiles <9.5 40 (24.7) 40 (25.3) Ref 48 (25.3) Ref 9.5–12.0 50 (30.9) 37 (23.4) 0.8 (0.4–1.5) 48 (25.3) 0.9 (0.5–1.6) 12.1–15.0 33 (20.4) 41 (25.9) 1.3 (0.7–2.4) 40 (21.1) 1.0 (0.5–1.8) ≥15.1 39 (24.1) 40 (25.3) 1.2 (0.6–2.2) 54 (28.4) 1.2 (0.6–2.2) P for trend 0.389 0.541 Age first began wearing a bra, y ≤12 162 (34.5) 145 (31.9) Ref 185 (31.4) Ref 13–14 217 (46.3) 213 (46.9) 1.1 (0.8–1.4) 303 (51.4) 1.2 (0.9–1.6) ≥15 90 (19.2) 96 (21.1) 1.2 (0.8–1.7) 102 (17.3) 1.0 (0.7–1.4) P for trend 0.426 0.903 Bra cup size 1 year before the reference date A 17 (3.7) 34 (7.6) 1.9 (1.0–3.6) 43 (7.4) 1.8 (1.0–3.3) B 152 (32.7) 144 (32.1) Ref 203 (34.9) Ref C 166 (35.7) 157 (35.0) 1.0 (0.7–1.3) 176 (30.3) 0.8 (0.6–1.1) D or above 130 (28.0) 113 (25.2) 0.9 (0.7–1.3) 159 (27.4) 0.9 (0.7–1.3) P for trend 0.138 0.095 NOTE: All analysis adjusted for age at the reference date, reference year, and county.
The numbers in the column may not add up to the total case/control numbers due to missingness in some of the bra wearing variables.