Antiplatelet drugs and breast cancer risk in a large nationwide Danish case-control study.

"we compared the use of antiplatelet drugs among women diagnosed with invasive breast cancer (cases) with use among cancer-free women (controls) estimating odds ratios (ors) for breast cancer associated with antiplatelet drug use 2 1 we used data from six nationwide registry sources: the danish cancer registry the national prescription registry the national patient registry the population education registry the danish pathology register and the civil registration system we described these registries in data s1 (additional file 1).; all linkages were performed by statistics denmark a government institution that collects and processes information for a variety of statistical and scientific purposes2 2 we described the selection of breast cancer cases in figure 1 and codes for cancer diagnoses in data s2 (additional file 1).; we described codes for drug exposure in data s2 (additional file 1).; codes for all covariates are listed in data s2 (additional file 1) 2 5 we computed the frequency and proportion of cases and controls within categories of exposure and covariates.; all models were adjusted for all potential confounders outlined previously and listed in the data s3 .; table 2 associations between antiplatelet drug use and invasive breast cancer risk n cases n controls or (95% ci) a or (95% ci) b low-dose aspirin use categories never use 60 268 603 363 1 00 (ref) 1 00 (ref) ever use 8548 84 797 1 01 (0 99-1 04) 1 00 (0 97-1 03) long-term use 5186 50 867 1 02 (0 99-1 06) 1 00 (0 97-1 04) cumulative ddds never use 60 268 603 363 1 00 (ref) 1 00 (ref) <500 1822 17 895 1 02 (0 97-1 07) 1 00 (0 95-1 06) >=500 to <1000 1540 16 035 0 96 (0 91-1 02) 0 95 (0 90-1 00) >=1000 to <2000 2197 21 785 1 01 (0 97-1 06) 1 00 (0 95-1 05) >=2000 to <3000 1437 14 046 1 03 (0 97-1 09) 1 02 (0 96-1 08) >=3000 1552 15 036 1 04 (0 98-1 09) 1 03 (0 97-1 09) or per 1000 ddds8548 84 797 1 01 (1 00-1 02) 1 01 (0 99-1 02) clopidogrel use categories never use 67 737 676 397 1 00 (ref) 1 00 (ref) ever use 1079 11 763 0 91 (0 86-0 97) 0 93 (0 87-1 00) long-term use 287 2981 0 96 (0 85-1 08) 0 96 (0 85-1 09) cumulative ddds never use 67 737 676 397 1 00 (ref) 1 00 (ref) <500 533 6226 0 85 (0 78-0 93) 0 87 (0 79-0 96) >=500 to <1000 259 2556 1 01 (0 89-1 15) 1 02 (0 89-1 16) >=1000 to <2000 196 1947 1 00 (0 87-1 16) 1 01 (0 87-1 17) >=2000 to <3000 60 599 1 00 (0 76-1 30) 1 00 (0 77-1 31) >=3000 31 435 0 71 (0 49-1 02) 0 71 (0 49-1 02) or per 1000 ddds1079 11 763 0 96 (0 91-1 01) 0 97 (0 91-1 03) dipyridamole use categories never use 67 792 677 946 1 00 (ref) 1 00 (ref) ever use 1024 10 214 1 00 (0 94-1 07) 1 02 (0 94-1 10) long-term use 527 5205 1 01 (0 92-1 11) 1 03 (0 93-1 14) cumulative ddds never use 67 792 677 946 1 00 (ref) 1 00 (ref) <500 316 3204 0 99 (0 88-1 11) 0 99 (0 87-1 11) >=500 to <1000 181 1805 1 00 (0 86-1 17) 1 02 (0 87-1 20) >=1000 to <2000 250 2455 1 02 (0 89-1 16) 1 04 (0 91-1 19) >=2000 to <3000 145 1531 0 95 (0 80-1 12) 0 96 (0 81-1 15) >=3000 132 1219 1 08 (0 90-1 30) 1 12 (0 93-1 35) or per 1000 ddds1024 10 214 1 01 (0 98-1 05) 1 02 (0 98-1 06) abbreviations: ci confidence interval; ddd defined daily dose; or odds ratio a adjusted for age and calendar time (by risk-set matching and the conditional analysis) b adjusted for age and calendar time (by risk-set matching and the conditional analysis) and covariates listed in the data s3 .; table 3 associations of antiplatelet drug use with risk of invasive breast cancer stratified by age at index date age < 55 years age >= 55 and <70 years age >= 70 years p heterogeneity n cases n controls or (95% ci) a n cases n controls or (95% ci) a n cases n controls or (95% ci) a low-dose aspirin use categories never use 19 788 197 360 1 00 (ref) 27 448 274 983 1 00 (ref) 13 032 131 020 1 00 (ref) ever use 401 4530 0 95 (0 85-1 07) 3228 31 777 0 98 (0 94-1 03) 4919 48 490 1 00 (0 96-1 05) 64 long-term use 130 1765 0 81 (0 66-0 99) 1816 17 714 0 99 (0 93-1 05) 3240 31 388 1 02 (0 97-1 07) 05 cumulative ddds never use 19 788 197 360 1 00 (ref) 27 448 274 983 1 00 (ref) 13 032 131 020 1 00 (ref) <500 181 1816 1 04 (0 89-1 22) 765 7600 0 97 (0 90-1 05) 876 8479 1 02 (0 94-1 09) >=500 to <1000 90 949 1 02 (0 82-1 28) 647 6463 0 97 (0 89-1 05) 803 8623 0 92 (0 85-0 99) >=1000 to <2000 80 1029 0 84 (0 66-1 07) 849 8311 0 99 (0 92-1 07) 1268 12 445 1 01 (0 95-1 08) >=2000 to <3000 29 471 0 67 (0 46-0 99) 504 4979 0 98 (0 89-1 08) 904 8596 1 05 (0 97-1 13) >=3000 21 265 0 85 (0 54-1 33) 463 4424 1 01 (0 91-1 12) 1068 10 347 1 04 (0 97-1 12) or per 1000 ddds401 4530 0 92 (0 84-1 00) 3228 31 777 1 00 (0 98-1 02) 4919 48 490 1 01 (0 99-1 03) clopidogrel use categories never use 20 120 201 096 1 00 (ref) 30 285 302 584 1 00 (ref) 17 332 172 717 1 00 (ref) ever use 69 794 1 00 (0 75-1 32) 391 4176 0 95 (0 85-1 07) 619 6793 0 92 (0 83-1 01) 80 long-term use 18 166 1 28 (0 77-2 12) 107 982 1 07 (0 87-1 32) 162 1833 0 88 (0 75-1 05) 24 cumulative ddds never use 20 120 201 096 1 00 (ref) 30 285 302 584 1 00 (ref) 17 332 172 717 1 00 (ref) <500 42 459 1 07 (0 75-1 51) 191 2321 0 85 (0 73-1 00) 300 3446 0 87 (0 77-0 99) >=500 to <1000 9 169 0 60 (0 30-1 18) 93 873 1 06 (0 85-1 32) 157 1514 1 04 (0 88-1 24) >=1000 to <2000 17 110 1 74 (1 03-2 96) 72 683 1 03 (0 80-1 32) 107 1154 0 94 (0 76-1 15) >=2000 to <3000 < 5 39 (-) 23 166 1 37 (0 88-2 13) 36 394 0 92 (0 65-1 31) >=3000 < 5 17 (-) 12 133 0 89 (0 49-1 61) 19 285 0 67 (0 42-1 06) or per 1000 ddds69 794 0 89 (0 66-1 18) 391 4176 1 03 (0 94-1 13) 619 6793 0 95 (0 88-1 02) dipyridamole use categories never use 20 141 201 316 1 00 (ref) 30 287 303 094 1 00 (ref) 17 364 173 536 1 00 (ref) ever use 48 574 0 86 (0 62-1 19) 389 3666 1 03 (0 91-1 17) 587 5974 1 02 (0 93-1 13) 52 long-term use 12 226 0 51 (0 28-0 94) 209 1891 1 08 (0 92-1 28) 306 3088 1 05 (0 92-1 19) 005 cumulative ddds never use 20 141 201 316 1 00 (ref) 30 287 303 094 1 00 (ref) 17 364 173 536 1 00 (ref) <500 26 222 1 20 (0 79-1 84) 115 1132 0 98 (0 80-1 19) 175 1850 0 97 (0 82-1 14) >=500 to <1000 10 126 0 82 (0 42-1 58) 65 643 1 00 (0 77-1 31) 106 1036 1 07 (0 87-1 31) >=1000 to <2000 9 125 0 72 (0 36-1 45) 105 897 1 15 (0 93-1 42) 136 1433 1 00 (0 83-1 20) >=2000 to <3000 < 5 73 (-) 55 566 0 94 (0 71-1 25) 87 892 1 03 (0 82-1 29) >=3000 < 5 28 (-) 49 428 1 13 (0 83-1 53) 83 763 1 17 (0 92-1 48) or per 1000 ddds48 574 0 71 (0 53-0 95) 389 3666 1 03 (0 97-1 10) 587 5974 1 03 (0 98-1 08) abbreviations: ci confidence interval; ddd defined daily dose; or odds ratio a adjusted for age calendar time (by risk-set matching and the conditional analysis) and and covariates listed in the data s3 .; data s1 danish nationwide registries.; data s2 codes and definitions of outcome exposure and exclusion criteria.; data s3 codes and definitions of covariates."

"CONFLICT OF INTEREST Anton Pottegård reports participation in research projects funded by Alcon, Almirall, Astellas, Astra‐Zeneca, Boehringer‐Ingelheim, Novo Nordisk, Servier and LEO Pharma, all regulator‐mandated phase IV‐studies, all with funds paid to the institution where he was employed (no personal fees) and with no relation to the work reported in this paper. The other authors declare no conflict of interest."