Table 2.
Invasive breast cancer Hazard Ratios (HRs) and 95% Confidence Intervals (95% CI) associated with never/ever passive smoking exposures, by setting and by age of exposure, among 1,754 cases diagnosed 1997-2007 in 57,523 study participants.
| Passive Smoke Exposure | N | #cases | HR | 95% CI | HR | 95% CI |
|---|---|---|---|---|---|---|
| Adjusted for age and race | Adjusted for age, race and personal risk factors* | |||||
| Lifetime exposure: | ||||||
| Never | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Ever | 49,468 | 1,567 | 1.13 | 0.96, 1.33 | 1.10 | 0.94, 1.30 |
| Age-Specific Exposures: | ||||||
| Never | 7,070 | 163 | 1.00 | |||
| Any Age < 20 Exposure | 37,436 | 1,150 | 1.06 | 0.94, 1.19 | 1.06 | 0.94, 1.19 |
| Any Age ≥ 20 Exposure | 41,211 | 1,363 | 1.06 | 0.93, 1.21 | 1.04 | 0.91, 1.19 |
| Setting-Specific Exposures: | ||||||
| Never | 7,070 | 163 | 1.00 | - | 1.00 | - |
| Any Home Exposure | 40,773 | 1,312 | 1.05 | 0.93, 1.17 | 1.04 | 0.92, 1.16 |
| Any Work Exposure | 28,581 | 958 | 1.03 | 0.94, 1.14 | 1.02 | 0.93, 1.13 |
| Any Social Exposure | 21,390 | 698 | 1.01 | 0.91, 1.11 | 1.00 | 0.90, 1.10 |
*
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.