Table 4.
Adjusted hazard ratios and 95% confidence intervals from Cox proportional hazards modeling of smoking status stratified by alcohol consumption
| Overall BC | ER-positive BC | ER-negative BC | ||||||||
| Continuous FRP | Person years | BC | Model 1a | Model 2b | BC | Model 1a | Model 2b | BC | Model 1a | Model 2b |
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | |||||
| Regular drinkersd | ||||||||||
| Never smoker | 40,334.3 | 216 | Reference | Reference | 90 | Reference | Reference | 24 | Reference | Reference |
| Former smoker | 31,831.4 | 219 | 1.16 (0.96, 1.41) | 1.23 (0.99, 1.53) | 97 | 1.24 (0.93, 1.65) | 1.25 (0.89, 1.75) | 24 | 1.17 (0.64, 2.17) | 1.08 (0.55, 2.12) |
| Current smoker | 16,742.8 | 90 | 1.07 (0.83, 1.36) | 0.84 (0.63, 1.13) | 35 | 1.12 (0.76, 1.65) | 0.99 (0.62, 1.60) | 20 | 1.77 (0.91, 3.46) | 0.95 (0.43, 2.07) |
| Former smoker*FRP | 0.93 (0.78, 1.09) | 0.99 (0.74, 1.34) | 1.10 (0.83, 1.46) | |||||||
| Current smoker*FRP | 1.39 (1.13, 1.71) | 1.21 (0.80, 1.85) | 1.67 (1.16, 2.40) | |||||||
| Non-regular drinkers | ||||||||||
| Never smoker | 62,284.47 | 343 | Reference | Reference | 145 | Reference | Reference | 61 | Reference | Reference |
| Former smoker | 15,157.38 | 83 | 0.88 (0.69, 1.12) | 0.90 (0.67, 1.21) | 21 | 0.54 (0.34, 0.86) | 0.63 (0.36, 1.10) | 15 | 0.95 (0.53, 1.72) | 0.93 (0.45, 1.89) |
| Current smoker | 9692.36 | 47 | 0.97 (0.71, 1.32) | 1.00 (0.69, 1.46) | 19 | 0.98 (0.61, 1.59) | 1.04 (0.59, 1.84) | 7 | 0.77 (0.34, 1.74) | 0.68 (0.23, 1.97) |
| Former smoker*FRPe | 0.98 (0.81, 1.17) | 0.82 (0.54, 1.25) | 1.02 (0.77, 1.35) | |||||||
| Current smoker*FRPe | 0.95 (0.70, 1.29) | 0.93 (0.61, 1.42) | 1.11 (0.69, 1.79) | |||||||
| Categorical FRP | 1-year FRP < 0.34% | 1-year FRP ≥ 0.34% | 1-year FRP < 0.34% | 1-year FRP ≥ 0.34% | 1-year FRP < 0.34% | 1-year FRP ≥ 0.34% | ||||
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | |||||
| Regular drinkers | ||||||||||
| Former smoker | 1.16 (0.85, 1.59) | 1.16 (0.92, 1.47) | 1.04 (0.64, 1.69) | 1.32 (0.93, 1.88) | 0.60 (0.15, 2.44) | 1.38 (0.71, 2.7) | ||||
| Current smoker | 0.81 (0.51, 1.27) | 1.25 (0.94, 1.68) | 0.87 (0.42, 1.78) | 1.28 (0.80, 2.04) | 0.70 (0.13, 3.63) | 1.99 (0.98, 4.03) | ||||
| Non-regular drinkers | ||||||||||
| Former smoker | 0.88 (0.54, 1.42) | 0.89 (0.67, 1.18) | 0.68 (0.28, 1.65) | 0.52 (0.30, 0.90) | 1.61 (0.45, 5.77) | 0.83 (0.44, 1.57) | ||||
| Current smoker | 1.11 (0.65, 1.90) | 0.91 (0.62, 1.35) | 0.97 (0.39, 2.45) | 1.06 (0.60, 1.88) | 1.10 (0.22, 5.43) | 0.66 (0.26, 1.68) | ||||
BC breast cancer, HR hazard ratio, CI confidence interval, ER estrogen receptor expression, FRP familial risk profile
aModel 1 = Adjusted Cox models which are stratified by birth cohort (< 1950, 1950–1959, 1960–1969, ≥ 1970) and adjusted for study site, race/ethnicity, body mass index, education, and hormonal birth control use
bModel 2 = Interaction models that include an interaction term with FRP as estimated by 1-year BOADICEA risk score
cSmokers are defined as having smoked at least one cigarette per day for 3 months or longer
dRegular drinkers are defined as consuming one alcoholic beverage at least once a week for 6 months or longer