Table 2.

Multivariate RRs (95% CI) of breast cancer according to cross-classified luteal urinary EM and luteal plasma estrogens, among ovulatory women only in the Nurses' Health Study II

	Urine/Plasma levels*
	Low/Low	Low/High	High/Low	High/High
Estrone: luteal urine & luteal plasma
	1.00 (ref)	0.85 (0.52–1.39)	0.56 (0.32–0.97)	0.65 (0.43–0.99)
Estradiol: luteal urine & luteal plasma
	1.00 (ref)	1.19 (0.74–1.90)	0.63 (0.35–1.13)	0.67 (0.43–1.05)
Estrone: luteal urine & follicular plasma
	1.00 (ref)	0.97 (0.61–1.53)	0.68 (0.41–1.14)	0.64 (0.40–1.04)
Estradiol: luteal urine & follicular plasma
	1.00 (ref)	0.97 (0.61–1.54)	0.60 (0.36–1.01)	0.58 (0.34–0.97)

Multivariate models adjusted for: first morning urine (yes, no), BMI at age 18 (<21, 21–<23, ≥23), age at menarche (<12, 12, 13, ≥14), parity & age at first birth (nulliparous, 1–2 children & <25 yrs, 1–2 children & 25–29 yrs, 1–2 children & ≥30 yrs, ≥3 children & <25 yrs, ≥3 children & ≥25 yrs), family history of breast cancer (yes, no), history of benign breast disease (yes, no)

^*Cutpoints based on medians of urine and plasma levels