Table 3.

Adjusted hazard ratios and 95% confidence intervals from Cox proportional hazards modeling of 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)
Non-regular drinkerc	90,009.0	492	Reference	Reference	192	Reference	Reference	85	Reference	Reference*
< 7 drinks/week	48,947.2	275	0.99 (0.85, 1.16)	1.01 (0.84, 1.21)	122	1.07 (0.84, 1.36)	1.14 (0.85, 1.52)	36	0.69 (0.46, 1.04)	0.64 (0.40, 1.04)
≥ 7 drinks/week	29,982.8	193	1.10 (0.92, 1.32)	1.22 (0.99, 1.50)	80	1.15 (0.87, 1.51)	1.48 (1.08, 2.02)	30	0.89 (0.57, 1.39)	0.84 (0.51, 1.40)
< 7 drinks/week*FRP				0.99 (0.87, 1.12)			0.92 (0.74, 1.15)			1.06 (0.87, 1.29)
≥ 7 drinks/week*FRP				0.88 (0.76, 1.01)			0.68 (0.52, 0.89)			1.04 (0.85, 1.27)
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)
Non-regular drinker			Reference	Reference		Reference	Reference		Reference	Reference
< 7 drinks/week			1.02 (0.77, 1.35)	0.96 (0.79, 1.16)		0.99 (0.64, 1.54)	1.10 (0.82, 1.48)		0.69 (0.26, 1.87)	0.65 (0.41, 1.03)
≥ 7 drinks/week			1.18 (0.87, 1.61)	1.05 (0.84, 1.31)		1.24 (0.76, 2.01)	1.09 (0.77, 1.53)		0.43 (0.13, 1.49)	0.98 (0.61, 1.58)

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, hormonal birth control use, and cigarette smoking

^bModel 2 = Interaction models that include an interaction term with FRP as estimated by 1-year BOADICEA risk score

^cRegular drinkers are defined as consuming one alcoholic beverage at least once a week for 6 months or longer