Table 3.
Association of alcohol intake and intake of specific beverages with risk of TNBC and ER+ breast cancer in the Women’s Health Initiative observational study and clinical trial combined
| TNBC cases | ER+ cases | |||||||
|---|---|---|---|---|---|---|---|---|
| (N = 300) | (N = 2,479) | |||||||
| N cases (%) | HRa | 95% CI | N cases (%) | HRa | 95% CI | |||
| Alcohol intake at baseline | ||||||||
| Never drank | 44 | (14.7) | 1.00 | reference | 239 | (11.1) | 1.00 | reference |
| Past drinker | 59 | (19.7) | 0.72 | 0.48–1.08 | 427 | (18.7) | 0.99 | 0.84–1.57 |
| <1 drink/month | 27 | (9.0) | 0.47 | 0.29–0.78 | 264 | (10.7) | 0.87 | 0.73–1.05 |
| <1 drink/week | 70 | (23.3) | 0.78 | 0.53–1.16 | 499 | (20.2) | 0.98 | 0.83–1.14 |
| 1–6 drinks/week | 73 | (24.4) | 0.68 | 0.46–1.02 | 666 | (27.0) | 1.00 | 0.86–1.17 |
| ≥7 drinks/week | 27 | (9.1) | 0.57 | 0.34–0.95 | 376 | (15.2) | 1.26 | 1.06–1.50 |
| Missing | 0 | 8 | ||||||
| Beer intake at baseline | ||||||||
| 0 | 239 | (79.7) | 1.00 | reference | 1935 | (78.1) | 1.00 | reference |
| <3 servings/week | 53 | (17.7) | 0.93 | 0.68–1.27 | 502 | (20.3) | 1.04 | 0.94–1.15 |
| ≥3 servings/week | 8 | (2.7) | 1.60 | 0.79–3.26 | 42 | (1.7) | 1.01 | 0.73–1.38 |
| P for trend | 0.74 | 0.51 | ||||||
| Wine intake at baseline | ||||||||
| 0 | 159 | (53.2) | 1.00 | reference | 1119 | (45.2) | 1.00 | reference |
| <3 servings/week | 116 | (38.7) | 0.95 | 0.73–1.22 | 1019 | (41.1) | 1.00 | 0.91–1.09 |
| ≥3 servings/week | 25 | (8.4) | 0.75 | 0.48–1.17 | 341 | (13.8) | 1.16 | 1.02–1.32 |
| P for trend | 0.25 | 0.08 | ||||||
| Liquor intake at baseline | ||||||||
| 0 | 220 | (73.3) | 1.00 | reference | 1750 | (70.6) | 1.00 | reference |
| <3 servings/week | 68 | (22.7) | 1.07 | 0.81–1.43 | 528 | (21.3) | 0.95 | 0.86–1.05 |
| ≥3 servings/week | 12 | (4.0) | 0.84 | 0.47–1.52 | 201 | (8.1) | 1.36 | 1.17–1.58 |
| P for trend | 0.93 | 0.02 | ||||||
Adjusted for the following variables: age (continuous), education (3 levels), ethnicity (3 levels), body mass index (kg/m2 -- continuous), waist circumference (cm – continuous), oralcontraceptive use (never, ever), hormone therapy (never, estrogen only, estrogen plus progestin, both), age at menarche (continuous), age at first birth (4 levels), age at menopause (3 levels), alcohol (servings per week – continuous), pack-years of smoking (0, <20, 20–<40, ≥40), family history of breast cancer (no, yes), history of breast biopsy (never, ever, missing), mammogram with past 2 years (no, yes), physical activity (METs/week - continuous), and treatment/control arm assignment in the estrogen alone, estrogen plus progestin, calcium plus vitamin D, and dietary modification trials.