Table 3.
Invasive breast cancer Hazard Ratios (HRs) and 95% Confidence Intervals (95% CI) associated with years, intensity, and intensity-years of passive smoke exposure for 1,754 cases diagnosed 1997-2007 among 57,523 study participants.
| Exposure | N | #cases | HR | 95% CI | HR | 95% CI |
|---|---|---|---|---|---|---|
| Adjusted for age and race | Adjusted for age, race and personal risk factors* | |||||
| Years:** | ||||||
| Lifetime Exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Low (≤15.0) | 16,551 | 436 | 1.12 | 0.94, 1.34 | 1.10 | 0.92, 1.32 |
| Medium (15.1 – 30.0) | 16,314 | 495 | 1.13 | 0.94, 1.35 | 1.10 | 0.92, 1.32 |
| High (>30.0) | 16,299 | 629 | 1.14 | 0.96, 1.36 | 1.12 | 0.93, 1.33 |
| Age-Specific Exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Age <20 exposure: | ||||||
| Low (≤15.0) | 14,719 | 441 | 1.13 | 0.99, 1.29 | 1.13 | 0.99, 1.29 |
| Medium (15.1 – 30.0) | 19,167 | 591 | 0.99 | 0.87, 1.13 | 0.99 | 0.87, 1.13 |
| High (>30.0) | 3,017 | 100 | 0.99 | 0.79, 1.24 | 0.98 | 0.78, 1.23 |
| Age ≥20 exposure: | ||||||
| Low (≤15.0) | 22,938 | 633 | 1.06 | 0.92, 1.22 | 1.04 | 0.90, 1.20 |
| Medium (15.1 – 30.0) | 8,888 | 308 | 1.01 | 0.86, 1.20 | 1.00 | 0.84, 1.18 |
| High (>30.0) | 8,934 | 409 | 1.19 | 1.01, 1.41 | 1.16 | 0.98, 1.38 |
| Intensity: | ||||||
| Lifetime Exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Low (≤2.0) | 25,544 | 778 | 1.11 | 0.94, 1.31 | 1.09 | 0.92, 1.29 |
| Medium (2.1 – 3.0) | 9,330 | 292 | 1.11 | 0.92, 1.35 | 1.08 | 0.89, 1.31 |
| High (>3.0) | 13,193 | 446 | 1.18 | 0.98, 1.41 | 1.14 | 0.95, 1.37 |
| Age-Specific Exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Age <20 exposure: | ||||||
| Low (≤2.0) | 26,243 | 820 | 1.07 | 0.95, 1.21 | 1.07 | 0.95, 1.21 |
| Medium (2.1 – 3.0) | 4,814 | 131 | 0.94 | 0.77, 1.15 | 0.95 | 0.77, 1.16 |
| High (>3.0) | 5,015 | 159 | 1.03 | 0.84, 1.26 | 1.04 | 0.85, 1.28 |
| Age ≥20 exposure: | ||||||
| Low (≤ 2.0) | 22,764 | 714 | 1.04 | 0.91, 1.20 | 1.03 | 0.89, 1.18 |
| Medium (2.1 – 3.0) | 7,469 | 244 | 1.08 | 0.90, 1.29 | 1.04 | 0.87, 1.24 |
| High (>3.0) | 9,341 | 346 | 1.17 | 0.98, 1.39 | 1.13 | 0.95, 1.34 |
| Intensity-years: | ||||||
| Lifetime exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Low (≤17.5) | 17,618 | 483 | 1.12 | 0.94, 1.34 | 1.10 | 0.92, 1.31 |
| Medium (17.6 – 42.0) | 14,356 | 447 | 1.13 | 0.94, 1.35 | 1.10 | 0.92, 1.32 |
| High (>42.0) | 15,886 | 580 | 1.14 | 0.96, 1.36 | 1.11 | 0.93, 1.32 |
| Age-Specific Exposures: | ||||||
| None | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Age <20 exposure: | ||||||
| Low (≤17.5) | 21,375 | 673 | 1.09 | 0.96, 1.23 | 1.09 | 0.96, 1.23 |
| Medium (17.6 – 42.0) | 10,156 | 295 | 0.97 | 0.83, 1.13 | 0.97 | 0.83, 1.13 |
| High (>42.0) | 4,195 | 127 | 0.99 | 0.80, 1.22 | 0.99 | 0.80, 1.22 |
| Age ≥20 exposure: | ||||||
| Low (≤ 17.5) | 21,514 | 604 | 1.06 | 0.92, 1.22 | 1.04 | 0.90, 1.20 |
| Medium (17.6 – 42.0) | 9,213 | 303 | 1.01 | 0.85, 1.19 | 0.99 | 0.83, 1.17 |
| High (>42.0) | 8,599 | 389 | 1.22 | 1.03, 1.44 | 1.18 | 1.00, 1.40 |
*
Personal risk factors include family history of breast cancer, age at menarche, pregnancy history, lifetime duration of breastfeeding, physical activity, alcohol consumption, body mass index, and categories of menopausal status with use of hormone therapy.
**
“Years” represents the sum of years of exposure across the three categories of home, work and social.