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. Author manuscript; available in PMC: 2016 Nov 1.
Published in final edited form as: Ann Epidemiol. 2015 Aug 28;25(11):824–831. doi: 10.1016/j.annepidem.2015.08.007

Table 2.

Associations Between Active and Passive Smoking History and Breast Cancer-specific, Non-cancer, and All-cause Mortality among Women Diagnosed with Invasive Breast Cancer, the Breast Cancer Health Disparities Study.
Breast cancer mortality (243 events) Non-cancer mortality (102 events) All-cause mortality (445 events)
Events Total HR 95% CI Events Total HR 95% CI Events Total HR 95% CI
Active smoke exposurea
Never smokers 146 1325 1.00 Referent 52 1325 1.00 Referent 251 1325
Smoking status
Ever 97 893 1.05 0.81, 1.38 50 893 1.68 1.12, 2.51 194 893 1.21 0.99, 1.47
  Former 48 595 0.79 0.57, 1.11 37 595 1.68 1.08, 2.60 111 595 1.00 0.79, 1.26
  Current 49 298 1.55 1.11, 2.16 13 298 1.68 0.90, 3.13 83 298 1.68 1.30, 2.17
Cigarettes/day
  <20 66 565 1.1 0.81, 1.48 27 565 1.37 0.86, 2.19 114 565 1.13 0.90, 1.42
  ≥20 31 324 0.98 0.65, 1.46 20 324 1.86 1.07, 3.23 77 324 1.29 0.99, 1.69
  ptrend 0.89 0.02 0.06
Duration, years
  <20 42 416 0.91 0.64, 1.30 14 416 1.29 0.71, 2.35 64 416 0.92 0.69, 1.22
  ≥20 55 465 1.24 0.90, 1.72 33 465 1.79 1.14, 2.81 126 465 1.47 1.14, 1.79
  ptrend 0.30 0.01 0.01
Pack-years
  <35 74 677 1.05 0.78, 1.40 29 677 1.33 0.84, 2.10 133 677 1.11 0.90, 1.38
  ≥35 15 135 1.43 0.82, 2.49 14 135 2.46 1.32, 4.59 45 135 1.82 1.30, 2.54
  ptrend 0.33 0.008 0.003
Recency, years
  <20 32 342 0.92 0.62, 1.38 14 342 1.34 0.72, 2.47 62 342 1.08 0.81, 1.44
  ≥20 16 251 0.65 0.38, 1.10 21 251 1.78 1.06, 3.01 47 251 0.92 0.67, 1.27
  ptrend 0.15 0.03 0.88
Long-term passive smoke exposureb
All women
  None 45 377 1.00 Referent 18 377 1.00 Referent 74 377 1.00 Referent
  Low 55 526 0.97 0.65, 1.45 18 526 0.59 0.30, 1.15 94 526 0.85 0.62, 1.16
  Moderate/high 104 901 1.09 0.75, 1.59 37 901 0.64 0.35, 1.18 192 901 0.95 0.71, 1.27
  ptrend 0.59 0.22 0.95
Never smokers
  None 36 321 1.00 Referent 14 321 1.00 Referent 59 321 1.00 Referent
  Low 34 341 1.00 0.62, 1.62 9 341 0.49 0.21, 1.16 58 341 0.92 0.63, 1.33
  Moderate/high 51 395 1.34 0.86, 2.09 12 395 0.54 0.24, 1.22 78 395 1.08 0.76, 1.54
  ptrend 0.18 0.14 0.64
Recent passive smoke exposurec
All women
  None 123 1266 1.00 Referent 50 1266 1.00 Referent 227 1266 1.00 Referent
  Low 42 291 1.38 0.96, 1.99 13 291 1.49 0.80, 2.79 65 291 1.49 0.80, 2.79
  Moderate/high 39 247 1.54 1.04, 2.26 10 247 1.32 0.65, 2.67 68 247 1.32 0.65, 2.67
  ptrend 0.02 0.27 0.27
Never smokers
  None 79 816 1.00 Referent 28 816 1.00 Referent 139 816 1.00 Referent
  Low 24 152 1.43 0.89, 2.31 4 152 1.13 0.39, 3.31 32 152 1.29 0.86, 1.93
  Moderate/high 18 89 2.12 1.24, 3.63 3 89 1.27 0.37, 4.34 24 89 1.83 1.17, 2.88
  ptrend 0.004 0.67 0.01

Abbreviations: 4-CBCS-4-Corners Breast Cancer Study; SFBCS-San Francisco Bay Area Breast Cancer Study

a

Active smoking estimates adjusted for age, study, ethnicity, stage, body mass index, alcohol consumption, and education; estimates by intensity and duration are among ever smokers; recency is defined as time since quitting smoking among former smokers only

b

Exposure to passive smoke is based on data available from 4-CBCS for 1,804 of the 2,218 cases included in this analysis; this variable captures long-term exposure to passive smoke and was based on the average of exposure hours/week reported for ages 15 and 30 years and during the referent year for women <50 years of age; and at ages 15, 30, and 50 years and during the referent year for women ≥50 years of age. Estimates are adjusted for 4-CBCS study sites, age, ethnicity, stage, body mass index, alcohol consumption, cigarette pack-years (included in model with everyone), and education

c

Exposure to passive smoke is based on data available from 4-CBCS for 1,804 of the 2,218 cases included in this analysis; this variable captures recent exposure to passive smoke and was based on the average of exposure hours/week during the referent year. Estimates are adjusted for 4-CBCS study sites, age, ethnicity, stage, body mass index, alcohol consumption, cigarette pack-years (included in model with everyone), and education.

Note: p-value for trend is the linear trend of the hazard ratios further categorized by smoking measures of intensity and duration; never smokers are the referent group for all active smoke exposure analyses and are included in the p-trend calculation.