Table 2.

Multivariate-adjusted RR (95% CI) for breast cancer by quartiles of plasma enterolactone

	Enterola ctone (nmol/L)
All	Cases	Q1	Q2	Q3	Q4	P trenda
Cases/controls		199/209	227/197	179/196	197/200
Cut-pointsb (nmol/L)		0–4	>4–11	>11–21	>21
Simple RRc	802	1.00	1.23 (0.92–1.64)	0.97 (0.72–1.30)	1.05 (0.79–1.40)	0.97
RRd	802	1.00	1.18 (0.86–1.62)	0.91 (0.66–1.25)	0.96 (0.70–1.33)	0.60
By subtype		Q1	Q2	Q3	Q4	P trenda
Invasive	553	1.00	1.32 (0.95–1.81)	1.15 (0.83–1.60)	1.16 (0.83–1.61)	0.38
In situ	218	1.00	1.06 (0.70–1.60)	0.72 (0.46–1.13)	0.82 (0.53–1.26)	0.22
ER+ PR+ e	373	1.00	1.49 (1.04–2.15)	1.23 (0.84–1.80)	1.23 (0.84–1.80)	0.28
ER- PR- e	89	1.00	0.97 (0.51–1.84)	1.18 (0.64–2.19)	1.05 (0.56–1.97)	0.76
ER+ PR- e	55	1.00	1.22 (0.56–2.67)	0.74 (0.31–1.75)	0.77 (0.32–1.82)	0.46

^aLinear trend test across log transformed median enterolactone levels of each quartile using the Wald test.

^bCut-points obtained from controls

^cConditioning on matching factors.

^dConditioning on matching factors and adjusting for family history of breast cancer (yes, no), history of benign breast disease (yes, no), OC use (never, ≤1yr, >1–5yr, >5yr), BMI at age 18 (continuous), weight change since age 18 (continuous), age at first birth and parity (nulliparous, 1–2 children and <25 y, 1–2 children and 25–29 y, 1–2 children and ≥30 y, ≥3 children and <25 y, ≥3 children and ≥25 y), age at menarche (continuous), antibiotics use within last month (yes, no), alcohol consumption (continuous), smoking (never, past and <10 y since quitting, past and ≥10 y since quitting, current), and physical activity (0–3.8, >3.8–11.1, >11.1–26.4, >26.4 MET-hrs/wk).

^ePolytomous logistic regression adjusting for matching factors and the same covariates as listed above. P-heterogeneity were 0.21 and 0.56 for invasive versus in situ and ER+/PR+, ER−/PR−, ER+/PR− tumors respectively.