Table 1.

Alcohol and Breast Cancer: Recent Epidemiological Studies.

Number	Study Design	Age (yearrs) at Baseline	Data Collection	Unit of Measurement	Outcomes	Ref
2017
1	Longitudinal cohort NIH-AARP Diet and Health Study 190,325 postmenopausal women	55–70	Self-report	Avg. alcohol consumption (g/day) in 12 mo. before questionnaire completion	Similar associations were found between alcohol consumption (0.01–10 g/day) and ductal carcinoma in situ (HR = 1.05 [0.93–1.19]) on the one hand and invasive ductal carcinomas (HR = 1.03 [0.97–1.08]) on the other	[108]
2	Prospective cohort Nurses’ Health Study II 93,835 US women	27–44	Semi-quantitative food questionnaire	Calculated total daily alcohol consumption	Alcohol consumption was not associated with breast cancer risk overall for intake of ≥10 g/day vs. nondrinking (HR = 1.07 [0.94–1.22]) Positive association between alcohol consumption and breast cancer was found among women with a family history and folate intake < 400 μg/day (HR = 1.82 [1.06–3.12])	[109]
3	Sister Study 50,884 women	35–74	Self-report	Lifetime alcohol intake	High lifetime alcohol intake (≥230 drinks/year) increased breast cancer risk (HR = 1.35 [1.15–1.58]) For binge drinking (HR = 1.29, [1.15–1.45])	[110]
2016
4	Prospective cohort Nurse’s Health Study 105,972 women	30–55	Semi-quantitative food frequency questionnaire	Cumulative average alcohol intake	10 g/day (HR = 1.1 [1.05–1.15 for luminal A]) and (HR = 1.16 [1.02–1.33 for HER2 BC]), but not with luminal B (HR = 1.08, [0.99–1.16)] Hormonal and non-hormonal mechanisms may play a role in this association	[111]
5	Case-control Carolina Breast Cancer Study; 781 Afr. Am. women; 1014 White women	25–50	Alcohol intake (self-report) most proximal to diagnosis	Drinks per week	Consuming more than 7 drinks/week was significantly associated with increased risk of ER− (OR = 2.17 [1.25–3.75]) and triple-negative (ER−/PR−/HER2–) in African American women but not in White women	[112]
2015
6	Cohort study French E3N-EPIC 66,481 women	40–65	Self-report diet-history questionnaire	Cumulative average drinks/day	No association was found between drinking ≥2 drinks/day (beer, wine or spirits) and increase in breast cancer risk in premenopausal period ≥2 drinks/day of beer or wine was associated with increased breast cancer risk (HR = 1.85 [1.19–2.89], 1.33 [1.11–1.58]) in postmenopausal period This relationship was observed primarily in ER+/PR+ breast cancer risk (HR = 1.32 [1.08–1.60])	[113]
7	Prospective EPIC Study 334,850 women	35–70	Dietary and lifestyle questionnaires	Average lifetime alcohol intake	10 g/day increased breast cancer risk by 4.2% For intake of 5.1–15 g/day ER+/PR+ (HR = 1.09 [1.00–1.18]) ER+/PR− (HR = 1.13 [0.97–1.31) ER−/PR−/HER2– (HR = 1.18 [0.84–1.66]) Association between alcohol and breast cancer	[114]
8	Case-control 585 cases	28–90	Self-administered questionnaire	Total number of alcoholic drinks per week	<5 drinks per week was associated with increased risk of ER+ tumors In postmenopausal women: ER+ (OR = 2.32 [1.4–3.84]); ER+/PR− (OR = 2.92 [1.29–6.63]); ER+/PR+ (OR = 1.97 [1.08–3.57])	[115]
9	Prospective 45,233 women	30–49	Self-report	Current number of drinks/week converted to g/day	Alcohol intake was not statistically significantly associated with breast cancer risk, either overall or in different hormone receptor subtypes Overall, breast cancer risk increased with increasing alcohol intake among women with BMI <25 kg/m2	[116]
10	Prospective NHS	30–55	Self-report	Cumulative average intake per day	ER+/PR+/AR+ (HR per drink/day = 1.11 [1.06–1.17]) (AR = androgen receptor) ER−/PR−/AR− (HR per drink/day = 0.99 [0.88–1.12])	[117]
11	Prospective cohorts (2) Danish	50+	Self-report	Avg. drinks per week	Marked increase in breast cancer risk for hormone replacement therapy especially when combined with alcohol This effect was primarily restricted to ER+ cases	[118]
2013 and previous
12	Case Control, 2013 Japanese cohort 1754 pre- and postmenopausal women	20–79	Self-reported alcohol drinking	Avg. consumption g/day	23 g/day (OR = 1.39 [95% CI: 1.07–1.80]) in postmenopausal women ER−/PR−/HER2+ (OR = 2.99 [1.08–8.26]) ER−/PR−/HER2− (OR = 3.72 [1.30–10.67]) No significant positive association was observed among premenopausal women Among postmenopausal women, no protective effect of folate was obvious across all subtypes, except ER−/PR−/HER2− (OR = 0.44 [0.20–0.96])	[119]
13	Prospective observational, 2011 Nurses’ Health Study 105,986 women	Avg. 60	Semiquantitative food frequency questionnaire	Avg. daily consumption in g/day	At 5–9.9 g/day, or 0.5–1.0 drink: ER+/PR+ (RR = 1.14 [1.02–1.28]) ER−/PR− (RR = 1.25 [1.01–1.54]) ER+/PR− (RR = 1.07 [0.85–1.34]) ER−/PR+ (RR = 1.47 [0.87–2.47]) Low levels of alcohol were associated with a small increase in breast cancer risk	[120]
14	Prospective control, 2011 Japanese cohort 19,227 patients	40–64	Food frequency questionnaire	Avg. consumption g/day	≥15 g/day, no significant relation to breast cancer risk Moderate drinking does not increase breast cancer risk	[121]
15	Prospective, 2010 50,757 pre- and postmenopausal Japanese women	40–69	Self-reported questionnaires	Average consumption g/week	>150 g/week RR = 1.78 (premenopausal), 1.21 (postmenopausal) No effect of folate, body weight, flushing due to defective ALDH2	[122]
16	Case control, 2008 437 women	25–85	Structured questionnaire administered by two interviewers	Average consumption g/day	<1.5 g/day decreases risk of breast cancer (OR = 0.58 [0.34–0.97]) Moderate drinking decreases risk of breast cancer	[123]