Table 3.

Associations of alcohol with breast density measures by woman’s postmenopausal hormone therapy status^a

	N	Percent density (β and 95% CI)	Absolute dense area (β and 95% CI)	Non-dense area (β and 95% CI)
Never used hormones
Alcohol use
0	282	Ref	Ref	Ref
0–<5	244	−0.16 (−0.42, 0.10)	−0.08 (−0.49, 0.34)	0.11 (−0.39, 0.61)
≥5	216	−0.15 (−0.43, 0.12)	−0.40 (−0.83, 0.04)	−0.32 (−0.84, 0.21)
P for trend	742	0.42	0.06	0.14
Continuous, per 10g	742	−0.09 (−0.21, 0.03)	−0.23 (−0.42, −0.03)	−0.15 (−0.38, 0.08)
Current HT
Alcohol use
0	326	Ref	Ref	Ref
0–<5	326	−0.02 (−0.25, 0.22)	0.03 (−0.35, 0.41)	0.18 (−0.26, 0.63)
≥5	273	0.16 (−0.09, 0.41)	0.23 (−0.18, 0.63)	−0.23 (−0.72, 0.25)
P for trend	925	0.15	0.25	0.17
Continuous, per 10g	925	0.08 (−0.03, 0.20)	0.04 (−0.14, 0.22)	−0.20 (−0.42, 0.01)
Past HT
Alcohol use
0	156	Ref	Ref	Ref
0–<5	137	−0.00 (−0.37, 0.36)	0.02(−0.51, 0.56)	−0.11 (−0.80, 0.57)
≥5	122	0.12 (−0.27, 0.50)	−0.26 (−0.83, 0.31)	−0.79 (−1.51, −0.07)
P for trend	415	0.51	0.30	0.02
Continuous, per 10g	415	0.01 (−0.19, 0.22)	−0.12 (−0.43, 0.18)	−0.24 (−0.63, 0.15)
Current E+P
Alcohol use
0	105	Ref	Ref	Ref
0–<5	109	−0.16 (−0.58; 0.25)	0.15 (−0.52; 0.82)	0.81 (−0.04; 1.66)
≥5	116	0.15 (−0.27; 0.56)	0.37 (−0.29; 1.03)	−0.00 (−0.84; 0.84)
P for trend	330	0.26	0.29	0.41
Continuous, per 10g	330	0.05 (−0.12; 0.22)	0.06 (−0.21; 0.33)	−0.15 (−0.49; 0.20)

Abbreviations: HT – hormone therapy; E+P – estrogen + progesterone therapy

^aAdjusted for age (continuous), BMI (continuous), age at menarche (<12, 12, 13, >13), a family history of breast cancer (Yes/No), a history of benign breast disease (Yes/No), NHS cohort (NHSI, NHSII), age at menopause (<46, 46-<50, 50-<55, ≥55, unknown), and parity and age at first child’s birth (nulliparous, parous with age at first birth <25, parous with age at first birth ≥25)

Note: p-values for Interactions of alcohol with HT: percent density p=0.19; absolute dense area p=0.42; non-dense area p=0.43