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Table 1 Baseline characteristics of women diagnosed with stage I–III, operable breast cancer in Denmark from 1996 to 2009, according to thyroid status at the time of breast cancer diagnosis

From: Hypothyroidism and the risk of breast cancer recurrence and all-cause mortality - a Danish population-based study

Characteristics Prevalent hypothyroidism Incident hypothyroidism
Thyroid status Follow-up time1 Thyroid status Follow-up time1
Normal (n = 34,191) Hypothyroidism (n = 1272) Normal Hypothyroidism Normal (n = 33,332) Hypothyroidism (n = 859) Normal Hypothyroidism
Calendar year of diagnosis, n (%)
 1996–1999 8059 (24) 199 (16) 47,917 1166 7888 (24) 171 (20) 47,339 679
 2000–2004 11,522 (34) 413 (32) 76,332 2562 11,226 (34) 296 (34) 75,204 1127
 2005–2009 14,610 (43) 660 (52) 81,280 3383 14,218 (43) 392 (46) 80,004 1276
Age at diagnosis, n (%)
 35–40 years 1172 (3) 11 (1) 7366 62 1147 (3) 25 (3) 7277 89
 40–49 years 6134 (18) 115 (9) 40,077 708 5961 (18) 176 (20) 39,441 637
 50–59 years 10,798 (32) 346 (27) 68,364 2089 10,511 (32) 287 (33) 67,281 1084
 60–69 years 11,020 (32) 494 (39) 64,885 2901 10,759 (32) 261 (30) 63,951 934
 70–79 years 4434 (13) 263 (21) 22,540 1208 4333 (13) 101 (12) 22,226 318
 ≥ 80 years 633 (2) 43 (3) 2296 144 621 (2) 12 (1) 2271 24
Menopausal status at diagnosis, n (%)
 Premenopausal 9378 (27) ≤ 1952 (−) 61,404 1158 9118 (27) ≤ 2652 (−) 60,452 952
 Postmenopausal 24,774 (72) 1083 (85) 143,944 5937 24,176 (73) 598 (70) 141,816 2128
 Unknown 39 (0) ≤ 52 (−) 181 17 38 (0) ≤ 52 (−) 180 2
Modified comorbidity status, n (%)3
 None 28,809 (84) 957 (75) 177,395 5510 28,093 (84) 716 (84) 174,781 2614
 Low 4587 (13) 258 (20) 24,591 1356 4466 (13) 121 (14) 24,182 409
 High 795 (2) 57 (4) 3542 245 773 (2) 22 (3) 3484 58
Tumour size, n (%)
 ≤ 20 mm 20,756 (61) ≤ 7752 (−) 128,360 4479 20,248 (61) ≤ 5152 (−) 126,463 1896
 21–50 mm 12,202 (36) 480 (38) 71,284 2497 11,873 (36) 329 (38) 70,186 1098
 ≥ 51 mm 1045 (3) 23 (2) 4878 113 1026 (3) 19 (2) 4795 83
 Unknown 188 (1) ≤ 52 (−) 1007 22 185 (1) ≤ 52 (−) 1003 4
Lymph node status, n (%)
 N0 18,396 (54) 724 (57) 111,451 4040 17,986 (54) 410 (48) 109,988 1463
 N1–3 10,391 (30) 353 (28) 66,956 2145 10,090 (30) 301 (35) 65,833 1123
 N4+ 5404 (16) 195 (15) 27,121 927 5256 (16) 148 (17) 26,625 496
UICC stage, n (%)
 I 13,433 (39) 519 (41) 81,013 2939 13,139 (39) 294 (34) 79,950 1063
 II 15,067 (44) 551 (43) 95,812 3206 14,654 (44) 413 (48) 94,303 1509
 III 5691 (17) 202 (16) 28,704 967 5539 (17) 152 (18) 28,194 510
Histological grade, n (%)4
 Low 9740 (28) 364 (29) 59,627 2029 9500 (29) 240 (28) 58,749 878
 Moderate 12,742 (37) 507 (40) 78,631 2918 12,397 (37) 345 (40) 77,351 1280
 High 6608 (19) 226 (18) 37,186 1170 6446 (19) 162 (19) 36,641 545
 Unknown 5101 (15) 175 (14) 30,085 995 4989 (15) 112 (13) 29,705 379
ER status, n (%)
 ER negative (0–9%) 6376 (19) 224 (18) 35,446 1111 6198 (19) 178 (21) 34,822 624
 ER positive (≥ 10%) 26,954 (79) 1031 (81) 164,836 5894 26,294 (79) 660 (77) 162,448 2388
 Unknown 861 (3) 17 (1) 5247 106 840 (3) 21 (3) 5176 70
HER-2 status, n (%)5
 Negative 11,551 (34) 474 (37) 63,723 2370 11,245 (34) 306 (36) 62,732 992
 Positive 2489 (7) 114 (9) 13,508 599 2426 (7) 63 (7) 13,317 191
 Unknown 20,151 (59) 684 (54) 128,298 4143 19,661 (59) 490 (57) 126,398 1900
Endocrine therapy and ER status, n (%)
 ET−/ER− 7010 (21) 231 (18) 39,283 1154 6819 (20) 191 (22) 38,615 667
 ET+/ER+ 17,592 (51) 679 (53) 113,800 4123 17,109 (51) 483 (56) 112,074 1725
 ET−/ER+ 9362 (27) 352 (28) 51,037 1771 9185 (28) 177 (21) 50,374 663
 ET+/ER− 227 (1) 10 (1) 1410 64 219 (1) 8 (1) 1384 26
Type of primary surgery, n (%)
 Mastectomy without radiotherapy 11,337 (33) 454 (36) 65,458 2379 11,101 (33) 236 (27) 64,585 873
 Mastectomy with radiotherapy 6897 (20) 187 (15) 41,418 1045 6692 (20) 205 (24) 40,708 710
 Lumpectomy with radiotherapy 15,957 (47) 631 (50) 98,653 3688 15,539 (47) 418 (49) 97,154 1499
Systemic therapy, n (%)
 No 2091 (6) 73 (6) 10,265 269 2046 (6) 45 (5) 10,089 176
 Yes 32,100 (94) 1199 (94) 195,265 6843 31,286 (94) 814 (95) 192,358 2906
Chemotherapy, n (%)
 No 23,233 (68) 965 (76) 135,848 5277 22,713 (68) 520 (61) 133,933 1915
 Yes 10,958 (32) 307 (24) 69,681 1835 10,619 (32) 339 (39) 68,514 1167
Endocrine therapy, n (%)
 No 16,117 (47) 577 (45) 88,710 2885 15,754 (47) 363 (42) 87,396 1314
 Yes 18,074 (53) 695 (55) 116,819 4227 17,578 (53) 496 (58) 115,051 1768
Radiotherapy, n (%)
 No 11,337 (33) 454 (36) 65,458 2379 11,101 (33) 236 (27) 64,585 873
 Yes 22,854 (67) 818 (64) 140,071 4733 22,231 (67) 623 (73) 137,862 2209
Co-medication at baseline, n (%)
 Simvastatin user 1791 (5) 135 (11) 9321 716 1753 (5) 38 (4) 9217 103
 Aspirin user 447 (1) 23 (2) 2540 117 439 (1) 8 (1) 2503 36
  1. 1In person-years. 2According to Danish Data Protection Law, cell with very few individuals are not allowed to be presented. 3Charlson Comorbidity Index (CCI) without cancer included (low: score of 1 or 2; high: score of 3 or more). 4Histological grade is based on a composite score including tubule formation, mitoses, and nuclear pleomorphy, all consistent of a score of 1, 2, or 3. The scores are summarised, and a total score of 3–5 is categorised as low grade, 6–7 as moderate grade, and 8–9 as high grade (http://www.dbcg.dk/PDF%20Filer/Kap_3_Patologi_22_juni_2017.pdf). 5Systematic recording of HER-2 status started in 2007 HER-2 is classified according to immunohistochemistry (Hercept test) and by fluorescent in situ hybridisation (FISH) (counts 60 dots, yet min 6 cells and max 60 cells). The ratio is given as gene/chromosome with 2 decimals. HER-2 positive includes ‘HER-2 score = 3 and FISH ≤ 2.00’. HER-2 negative includes ‘HER-2 score of 0, 1, or 2 and FISH ≤ 2.00’