Table 10

Studies of passive smoking and breast cancer risk

First author, study yearStudy designNo. of cases/controls (or no. in cohort)ComparisonOR (95% CI)a
Egan, 2002 (84)Cohort3140/7820630+ years lived with regular smoker vs. <51.0 (0.9–1.2)
Hirose, 1995 (57)Case-control1186/23163Husband smokes 20+ cigarettes/day vs. none1.3 (1.0–1.7)b
Smith, 1994 (73)Case-control755/755>20 pack-years lifetime exposure vs. none2.7 (1.1–6.6)c
Johnson, 2000 (60)Case-control869/90971+ “smoker-years”d vs. never exposed3.0 (1.7–1.8)e
Morabia, 1996 (67)Case-control244/1032>50 (hours/day-years) from husband smoking vs. none3.2 (1.5–6.5)
Lash, 1999 (61)Case-control266/765>20 years exposure to passive smoking vs. none2.1 (1.0–4.1)
Wartenburg, 2000 (88)Cohort669/146488Husband smoked 31+ years vs. no passive or active1.1 (0.9–1.4)f
  • a OR, odds ratio; CI, confidence interval.

  • b The results shown are for premenopausal women. Among postmenopausal women the OR was also 1.3 (0.9–1.8).

  • c The results for childhood and adulthood exposure to passive smoke shown separately were weaker (but similar) in magnitude from total lifetime exposure.

  • d “Smoker-years” is defined as the number of smokers at the subject’s home and office times years in the home and office.

  • e The results shown are for premenopausal women. There were not enough postmenopausal women in this exposure category.

  • f The endpoint examined was breast cancer mortality.