Table 1.

Relative risk (95% CI) of postmenopausal breast cancer according to quintiles of energy-adjusted folate

Folate	Quintiles of intake
	1	2	3	4	5	p for trend
Cases	395	355	366	347	349
Person-years	77,779	80,108	82,379	83,957	86,091
Median intake (μg/day)a	296	350	392	440	522
Age-adjusted	1.00	0.86(0.75–1.00)	0.86 (0.75–0.99)	0.80 (0.69–0.92)	0.78 (0.67–0.90)	0.0006
Multivariable-adjustedb	1.00	0.85 (0.73–0.98)	0.85 (0.73–0.98)	0.79 (0.68–0.91)	0.78 (0.67–0.90)	0.001

^aNutrients are adjusted for total energy intake

^bAdjusted for age, two-year follow-up period, region of residence, years of education (< 12,12–15 or ≥15), family breast cancer (0, 1 or >1 first degree relatives), history of benign breast disease (yes or no), age at menarche (< 12, 12 13 or ≥14), parity (0, ≤2 and age at first birth ≤30 years, ≥3 and age at first birth ≤30 years or age at first birth >30 years), breastfeeding (none, < 7, 7–12 or ≥12 months), years since last use of oral contraceptives (never, unknown date of last use, < 25, 25–29 or ≥30), age at menopause (< 45, 45–49, 50–54 or ≥55), years of hormone replacement therapy use (never, unknown duration, < 3, 3–5.9 or ≥6), regular mammographic evaluation (yes or no), height in cm, body mass index (quartiles), vitamin (other than vitamin B) supplement use (yes or no), alcohol intake (0, < 6, 2 or ≥6.2 gr/day) and physical activity (quartiles). Regular mammographic evaluation defined as a report of a recent mammogram in 1990, 1992, and 1993