Table 2.
Use of antihypertensive medications and risk of second primary contralateral breast cancer*
| Controls | Cases | ||||
|---|---|---|---|---|---|
| Use of antihypertensive medications |
n=661 | n=352 | |||
| n | % | n | % | OR (95% CI) | |
| Use of calcium channel blockers | |||||
| Never | 557 | 84 | 295 | 84 | Reference |
| Ever (≥ 6 mo) | 85 | 13 | 47 | 13.4 | 1.1 (0.7 ,1.6) |
| Unknown † | 0 | 1 | NA | ||
| Recency of use among ever users ‡ | |||||
| Former | 15 | 2.4 | 10 | 3 | 1.4 (0.6 ,3.5) |
| Current | 60 | 9.5 | 33 | 9.8 | 1.1 (0.7 ,1.7) |
| Duration of use among current users | |||||
| <2 y | 17 | 2.8 | 10 | 3 | 1.1 (0.5 ,2.6) |
| 2–3 y | 15 | 2.4 | 3 | 0.9 | 0.3 (0.1 ,1.6) |
| ≥3 y | 28 | 4.5 | 20 | 6.1 | 1.4 (0.7 ,2.6) |
| Use of β blockers | |||||
| Never | 535 | 81 | 289 | 82.3 | Reference |
| Ever (≥ 6 mo) | 97 | 15 | 54 | 15.4 | 1.0 (0.7 ,1.4) |
| Unknown † | 2 | 1 | NA | ||
| Recency of use among ever users | |||||
| Former | 14 | 2.2 | 7 | 2.1 | 1.2 (0.4 ,3.2) |
| Current | 75 | 12 | 41 | 12.2 | 1.0 (0.6 ,1.5) |
| Duration of use among current users | |||||
| <2 y | 20 | 3.3 | 9 | 2.7 | 0.8 (0.3 ,1.9) |
| 2–3 y | 12 | 2 | 8 | 2.4 | 1.3 (0.5 ,3.3) |
| ≥3 y | 43 | 7 | 24 | 7.3 | 0.9 (0.5 ,1.6) |
| Use of ACE inhibitors | |||||
| Never | 522 | 79 | 271 | 77.2 | Reference |
| Ever (≥ 6 mo) | 114 | 17 | 72 | 20.5 | 1.2 (0.9 ,1.8) |
| Unknown † | 1 | 1 | |||
| Recency of use among ever users | |||||
| Former | 20 | 3.2 | 11 | 3.3 | 1.0 (0.4 ,2.4) |
| Current | 80 | 13 | 54 | 16.1 | 1.3 (0.8 ,2.0) |
| Duration of use among current users | |||||
| <2 y | 31 | 5.1 | 21 | 6.5 | 1.2 (0.6 ,2.3) |
| 2–3 y | 13 | 2.2 | 11 | 3.4 | 1.7 (0.7 ,4.1) |
| ≥3 y | 36 | 6 | 22 | 6.8 | 1.1 (0.6 ,2.1) |
| Use of Diuretics | |||||
| Never | 449 | 68 | 238 | 68.4 | Reference |
| Ever (≥ 6 mo) | 177 | 27 | 96 | 27.6 | 1.0 (0.7 ,1.4) |
| Unknown † | 4 | 4 | |||
| Recency of use among ever users | |||||
| Former | 31 | 5.2 | 15 | 4.6 | 1.0 (0.5 ,2.1) |
| Current | 119 | 20 | 72 | 22.2 | 1.2 (0.8 ,1.7) |
| Duration of use among current users | |||||
| <2 y | 35 | 6.2 | 29 | 9.4 | 1.6 (0.9 ,2.8) |
| 2–3 y | 20 | 3.5 | 11 | 3.5 | 1.2 (0.5 ,3.0) |
| ≥3 y | 64 | 11 | 32 | 10.3 | 1.0 (0.6 ,1.7) |
ORs and 95% Cis were estimated using conditional logistic regression to account for matching factors (age, year of first breast cancer diagnosis, stage of risk breast cancer, county of residence and race/ethnicity). All models were additional adjusted for receipt of adjuvant hormone therapy, radiation therapy and chemotherapy. CI= confidence interval; OR=odds ratio.
To maximize the utility of data, patients who used multiple drugs of a same class and had missing duration of use for some of these drugs would be classified as ever users if known duration of use was ≥ 6 mo, or unknown users if known duration of use was < 6 mo.
Patients had any incomplete information on duration of use were dropped from analyses on recency and duration.