Table 5.

Relationship Between Cumulative Alcohol Consumption and Risk of Invasive Breast Cancer According to Family History and Folate Intake Combined^a Among US Women Aged 27–44 Years in Nurses’ Health Study II, 1991–2011

Cumulative Average Alcohol Intake, g/day	No. of Cases	Age-Adjusted		Multivariate-Adjustedb
		HR	95% CI	HR	95% CI
No Family History and High Folate Intake (≥400 μg/day)
0	412	1.00	Referent	1.00	Referent
0.1–4.9	744	1.02	0.91, 1.16	0.99	0.87, 1.12
5.0–9.9	187	0.91	0.76, 1.08	0.85	0.71, 1.01
≥10.0	178	1.05	0.88, 1.26	0.98	0.81, 1.18
Per 10-g/day increment		1.03	0.95, 1.11	1.00	0.92, 1.09
P for trend		0.99		0.50
No Family History and Low Folate Intake (<400 μg/day)
0	267	1.00	Referent	1.00	Referent
0.1–4.9	355	1.04	0.88, 1.22	0.97	0.83, 1.15
5.0–9.9	105	1.23	0.98, 1.54	1.09	0.87, 1.38
≥10.0	100	1.28	1.01, 1.61	1.13	0.89, 1.44
Per 10-g/day increment		1.13	1.03, 1.23	1.08	0.98, 1.20
P for trend		0.02		0.19
Family History and High Folate Intake (≥400 μg/day)
0	77	1.00	Referent	1.00	Referent
0.1–4.9	141	0.96	0.72, 1.29	0.94	0.70, 1.26
5.0–9.9	58	1.30	0.91–1.87	1.27	0.88–1.83
≥10.0	45	1.23	0.84–1.81	1.19	0.79–1.78
Per 10-g/day increment		1.10	0.94, 1.29	1.09	0.92, 1.29
P for trend		0.08		0.12
Family History and Low Folate Intake (<400 μg/day)
0	50	1.00	Referent	1.00	Referent
0.1–4.9	94	1.44	0.99, 2.08	1.42	0.97, 2.09
5.0–9.9	27	1.53	0.93, 2.52	1.40	0.82, 2.39
≥10.0	26	2.06	1.24, 3.43	1.82	1.06, 3.12
Per 10-g/day increment		1.31	1.11, 1.55	1.26	1.05, 1.51
P for trend		0.01		0.08

Abbreviations: CI, confidence interval; HR, hazard ratio.

^aP for interaction = 0.55.

^b A multivariate Cox proportional hazards regression model was used for statistical testing and was stratified by age (in months) and calendar year of the current questionnaire cycle. Results were adjusted for oral contraceptive use (never or ever), the combination of parity and age at first birth (nulliparous, parity 1–2 and age at first birth <25 years, parity 1–2 and age at first birth 25–29 years, parity 1–2 and age at first birth ≥30 years, parity ≥3 and age at first birth <25 years, or parity ≥3 and age at first birth ≥25 years), age at menarche (≤11, 12, 13, or ≥14 years), menopausal status and use of hormone therapy (premenopausal/unknown menopausal status, postmenopausal and never use of hormones, postmenopausal and past hormone use, or postmenopausal and current hormone use), body mass index (weight (kg)/height (m)²; <18.5, 18.5–19.9, 20.0–22.4, 22.5–24.9, 25.0–29.9, or ≥30.0), personal history of benign breast disease (yes or no), height (<62.0, 62.0–64.9, 65.0–67.9, or ≥68.0 inches (<157, 157–164, 165–172, or ≥173 cm)), smoking status (never, past smoker of <25 cigarettes/day, past smoker of ≥25 cigarettes/day, current smoker of <25 cigarettes/day, or current smoker of ≥25 cigarettes/day), and red meat intake (g/day, continuous).