Table 1.

Cox regression HRs and 95% CIs for the association between prediagnosis and at-diagnosis ETS exposure and mortality in the LIBCSP women diagnosed with breast cancer in 1996–1997 (N = 1,508)

All-cause mortality (deaths, n = 597)Breast cancer–specific mortality (deaths, n = 237)
ETS exposureAge adjustedMultivariable adjustedaAge adjustedMultivariable adjusteda
At-diagnosisDeathsCensoredHR (95% CI)HR (95% CI)DeathsCensoredHR (95% CI)HR (95% CI)
ETS exposure statusb
 Never1191761 (Ref.)1 (Ref.)492461 (Ref.)1 (Ref.)
 Former3765851.00 (0.81–1.23)0.98 (0.80–1.22)1418200.87 (0.63–1.21)0.89 (0.64–1.24)
 Current841381.25 (0.94–1.66)1.04 (0.78–1.40)381841.04 (0.68–1.59)0.98 (0.63–1.52)
Duration of ETS exposure
 Never1191761 (Ref.)1 (Ref.)492461 (Ref.)1 (Ref.)
 Former
  <15 years50911.05 (0.75–1.46)1.13 (0.80–1.59)241171.02 (0.62–1.66)1.10 (0.67–1.81)
  ≥15–<30 years1312890.89 (0.69–1.14)0.90 (0.69–1.16)603600.84 (0.57–1.23)0.84 (0.57–1.24)
  ≥30 years1751871.06 (0.84–1.34)1.00 (0.79–1.28)543080.90 (0.61–1.33)0.89 (0.60–1.33)
 Current
  <15 years771.74 (0.81–3.73)1.52 (0.70–3.27)<512
  ≥15–<30 years13221.59 (0.89–2.84)1.32 (0.74–2.36)6291.08 (0.46–2.55)0.97 (0.41–2.29)
  ≥30 years621061.14 (0.83–1.55)0.93 (0.67–1.29)301381.07 (0.68–1.69)1.01 (0.63–1.61)
ETS exposure recency
 Never1191761 (Ref.)1 (Ref.)492461 (Ref.)1 (Ref.)
 Former
  <5 years26411.05 (0.69–1.60)0.95 (0.62–1.47)12551.07 (0.57–2.01)0.99 (0.52–1.87)
  ≥5–<10 years47691.07 (0.77–1.51)1.00 (0.71–1.41)161000.82 (0.47–1.45)0.76 (0.43–1.35)
  ≥10 years3034750.99 (0.80–1.22)0.99 (0.79–123)1136650.86 (0.62–1.21)0.90 (0.64–1.27)
 Current841381.25 (0.94–1.66)1.04 (0.78–1.40)381841.04 (0.68–1.59)0.98 (0.63–1.53)
  • NOTE: LIBCSP participants diagnosed with breast cancer between August 1, 1996, and July 31, 1997, followed-up for vital status through December 31, 2014.

  • aAdjusted for age at diagnosis, BMI, marital status, income, alcohol intake, physical activity, and active cigarette smoking status.

  • bETS exposure status was defined as never, former, and current exposure to tobacco smoke from any household members.