Table 2.

Invasive breast cancer HRs and 95% CIs associated with never/ever passive smoking exposures, by setting and by age of exposure, among 1,754 cases diagnosed 1997 to 2007 in 57,523 study participants

Passive smoke exposurenNo. casesHR (95% CI)HR (95% CI)
Adjusted for age and raceAdjusted for age, race, and personal risk factors*
Lifetime exposure
    Never7,0701631.001.00
    Ever49,4681,5671.13 (0.96-1.33)1.10 (0.94-1.30)
Age-specific exposures
    Never7,0701631.00
    Any age <20 exposure37,4361,1501.06 (0.94-1.19)1.06 (0.94-1.19)
    Any age ≥20 exposure41,2111,3631.06 (0.93-1.21)1.04 (0.91-1.19)
Setting-specific exposures
    Never7,0701631.001.00
    Any home exposure40,7731,3121.05 (0.93-1.17)1.04 (0.92-1.16)
    Any work exposure28,5819581.03 (0.94-1.14)1.02 (0.93-1.13)
    Any social exposure21,3906981.01 (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 breast-feeding, physical activity, alcohol consumption, BMI, and categories of menopausal status with use of hormone therapy.