Table 2.

Association between ER in nonneoplastic tissue and breast cancer status, by study site

Site	Controls		Cases
Cells staining for ER	N	(%)	N	(%)	Crude OR (95% CI)	Age-adjusted OR (95% CI)
Both
<1%	66	(20.7)	23	(11.2)	1.0	1.0
1–5	79	(24.8)	27	(13.1)	1.0 (0.5–1.9)	0.9 (0.5–1.7)
6–10	70	(21.9)	51	(24.8)	2.1 (1.2–3.8)	1.5 (0.8–2.8)
11–33	54	(16.9)	40	(19.4)	2.1 (1.1–4.0)	1.3 (0.7–2.5)
34–66	37	(11.6)	34	(16.5)	2.6 (1.4–5.1)	1.4 (0.7–2.8)
>66	13	(4.1)	31	(15.0)	6.8 (3.1–15.3)	2.6 (1.1–6.2)
Toronto
<1%	63	(31.5)	21	(20.8)	1.0	1.0
1–5	66	(33.0)	23	(22.8)	1.0 (0.5–2.1)	0.9 (0.5–2.0)
6–10	43	(21.5)	27	(26.7)	1.9 (0.9–3.8)	1.2 (0.6–2.5)
11–33	17	(8.5)	17	(16.8)	3.0 (1.3–6.9)	1.4 (0.6–3.6)
>33	11	(5.5)	13	(12.9)	3.5 (1.4–9.1)	1.4 (0.5–3.9)
Kingston
≤10%	43	(37.6)	30	(28.6)	1.0	1.0
11–33	37	(31.1)	23	(21.9)	0.9 (0.4–1.8)	0.9 (0.4–1.7)
34–66	28	(23.5)	25	(23.8)	1.3 (0.6–2.6)	1.1 (0.5–2.4)
>66	11	(9.2)	27	(25.7)	3.5 (1.5–8.2)	2.7 (1.1–6.6)

CI, confidence interval; ER, estrogen receptors; OR, odds ratio.