Table 2.
Associations between cumulative average radon and breast cancer risk in NHSII from 1989 to 2013 (n = 112,639)
| Outcomea | Cases (n) | Person-years (n) | Basicb
HR (95% CI) |
Fully adjustedc
HR (95% CI) |
|---|---|---|---|---|
| Invasive breast cancer | ||||
| Radon quintile 1 | 803 | 496,494 | Referent | Referent |
| Radon quintile 2 | 810 | 503,957 | 1.03 (0.93, 1.13) | 1.02 (0.92, 1.14) |
| Radon quintile 3 | 797 | 503,121 | 1.01 (0.92, 1.12) | 1.02 (0.90, 1.14) |
| Radon quintile 4 | 745 | 499,349 | 0.94 (0.85, 1.04) | 0.96 (0.85, 1.08) |
| Radon quintile 5 | 811 | 499,773 | 1.02 (0.93, 1.13) | 1.06 (0.94, 1.21) |
| p for trend | 0.96 | 0.30 | ||
| Continuous radon (per IQR increase)d | 3966 | 2,502,695 | 0.99 (0.96, 1.02) | 1.01 (0.97, 1.04) |
| ER+ | ||||
| Radon quintile 1 | 490 | 496,797 | Referent | Referent |
| Radon quintile 2 | 471 | 504,288 | 0.98 (0.87, 1.12) | 0.99 (0.87, 1.14) |
| Radon quintile 3 | 498 | 503,420 | 1.04 (0.92, 1.18) | 1.07 (0.91, 1.24) |
| Radon quintile 4 | 439 | 499,621 | 0.91 (0.80, 1.03) | 0.96 (0.82, 1.12) |
| Radon quintile 5 | 475 | 500,089 | 0.98 (0.86, 1.11) | 1.05 (0.89, 1.23) |
| p for trend | 0.53 | 0.66 | ||
| Continuous radon (per IQR increase)d | 2373 | 2,504,215 | 0.99 (0.95, 1.03) | 1.01 (0.96, 1.05) |
| ER- | ||||
| Radon quintile 1 | 101 | 497,123 | Referent | Referent |
| Radon quintile 2 | 112 | 504,612 | 1.11 (0.85, 1.46) | 1.13 (0.84, 1.51) |
| Radon quintile 3 | 125 | 503,741 | 1.24 (0.96, 1.62) | 1.27 (0.92, 1.74) |
| Radon quintile 4 | 114 | 499,939 | 1.14 (0.87, 1.49) | 1.17 (0.84, 1.62) |
| Radon quintile 5 | 133 | 500,402 | 1.32 (1.02, 1.72) | 1.34 (0.97, 1.86) |
| p for trend | 0.06 | 0.15 | ||
| Continuous radon (per IQR increase)d | 585 | 2,505,817 | 1.05 (0.97, 1.13) | 1.03 (0.95, 1.12) |
| ER+/PR+ | ||||
| Radon quintile 1 | 417 | 496,859 | Referent | Referent |
| Radon quintile 2 | 420 | 504,332 | 1.03 (0.90, 1.18) | 1.06 (0.91, 1.23) |
| Radon quintile 3 | 441 | 503,469 | 1.09 (0.95, 1.24) | 1.13 (0.96, 1.33) |
| Radon quintile 4 | 384 | 499,675 | 0.94 (0.81, 1.08) | 1.01 (0.85, 1.19) |
| Radon quintile 5 | 412 | 500,148 | 1.00 (0.87, 1.15) | 1.10 (0.92, 1.30) |
| p for trend | 0.61 | 0.60 | ||
| Continuous radon (per IQR increase)d | 2074 | 2,504,483 | 0.99 (0.95, 1.04) | 1.01 (0.97, 1.06) |
| ER−/PR- | ||||
| Radon quintile 1 | 89 | 497,137 | Referent | Referent |
| Radon quintile 2 | 93 | 504,633 | 1.05 (0.79, 1.41) | 1.07 (0.78, 1.46) |
| Radon quintile 3 | 104 | 503,763 | 1.18 (0.89, 1.57) | 1.19 (0.85, 1.68) |
| Radon quintile 4 | 104 | 499,946 | 1.19 (0.89, 1.58) | 1.20 (0.85, 1.69) |
| Radon quintile 5 | 123 | 500,409 | 1.41 (1.07, 1.85) | 1.38 (0.97, 1.96) |
| p for trend | 0.01 | 0.05 | ||
| Continuous radon (per IQR increase)d | 513 | 2,505,889 | 1.08 (0.99, 1.16) | 1.05 (0.96, 1.15) |
| ER+/PR- | ||||
| Radon quintile 1 | 70 | 497,167 | Referent | Referent |
| Radon quintile 2 | 47 | 504,679 | 0.69 (0.48, 1.00) | 0.62 (0.41, 0.93) |
| Radon quintile 3 | 53 | 503,818 | 0.77 (0.54, 1.11) | 0.66 (0.42, 1.02) |
| Radon quintile 4 | 53 | 499,984 | 0.76 (0.53, 1.09) | 0.67 (0.43, 1.04) |
| Radon quintile 5 | 62 | 500,458 | 0.87 (0.61, 1.22) | 0.75 (0.48, 1.18) |
| p for trend | 0.88 | 1.00 | ||
| Continuous radon (per IQR increase)d | 285 | 2,506,105 | 0.97 (0.87, 1.09) | 0.98 (0.86, 1.11) |
| ER−/PR−/HER2- | ||||
| Radon quintile 1 | 49 | 497,173 | Referent | Referent |
| Radon quintile 2 | 53 | 504,676 | 1.09 (0.74, 1.60) | 1.09 (0.71, 1.67) |
| Radon quintile 3 | 52 | 503,820 | 1.07 (0.72, 1.58) | 1.06 (0.67, 1.68) |
| Radon quintile 4 | 61 | 499,980 | 1.25 (0.86, 1.83) | 1.24 (0.78, 1.97) |
| Radon quintile 5 | 78 | 500,452 | 1.61 (1.12, 2.31) | 1.52 (0.96, 2.41) |
| p for trend | 0.003 | 0.02 | ||
| Continuous radon (per IQR increase)d | 293 | 2,506,101 | 1.12 (1.01, 1.24) | 1.09 (0.97, 1.23) |
a Radon quintile 1: <27.0 Bq/m3; quintile 2: ≥27.0–37.7 Bq/m3; quintile 3: ≥37.7–50.1 Bq/m3; quintile 4: ≥50.1–74.9 Bq/m3; quintile 5: ≥74.9 Bq/m3
b Adjusted for age, race
c Additionally adjusted for Census tract median home value, Census tract median income, marital status, living arrangements, individual-level income, region of residence, family history of breast cancer, screening mammography, personal history of biopsy-confirmed BBD, age at menarche, parity, age at first birth, lactation, menopausal status and hormone use (among postmenopausal women only), height, BMI at age 18, change in BMI since age 18, smoking status, physical activity, adult alcohol consumption, PM2.5, population density
d An IQR increase in cumulative average radon is 37.3 Bq/m3