Estimated dietary dioxin exposure and breast cancer risk among women from the French E3N prospective cohort

Breast Cancer Research

Table 4 Hazard ratios for pre- and postmenopausal breast cancer risk for increased intake of 0.43 pg/kg body weight/day, according to quartiles of estimated dietary dioxin exposure (n = 63,830), 1993 to 2008

		Dietary dioxin exposure (pg/kg body weight/day)
Populations	/0.43	<0.98 (ref)	[0.98, 1.23]	[1.23, 1.52]	≥1.52	P -trend
Premenopausal women ^c
Cases, n	446	104	105	117	120
HR (95% CI)^a	1.03 (0.94, 1.13)	1.00	0.93 (0.71, 1.22)	0.96 (0.74, 1.25)	0.94 (0.73, 1.23)	0.5705
HR (95% CI)^b	0.98 (0.87, 1.12)	1.00	0.84 (0.63, 1.11)	0.83 (0.62, 1.11)	0.77 (0.54, 1.08)	0.7873
Postmenopausal women ^d
Cases, n	3019	775	749	731	764
HR (95% CI)^a	1.01 (0.98, 1.05)	1.00	0.97 (0.88, 1.08)	0.96 (0.87, 1.06)	1.03 (0.93, 1.14)	0.5134
HR (95% CI)^b	0.98 (0.93, 1.03)	1.00	0.94 (0.84, 1.04)	0.90 (0.80, 1.01)	0.93 (0.82, 1.06)	0.3827
ER+/PR+ ^e
Cases, n	1365	354	336	325	350
HR (95% CI)^a	1.02 (0.96, 1.07)	1.00	0.96 (0.82, 1.11)	0.94 (0.81, 1.09)	1.03 (0.89, 1.20)	0.5837
HR (95% CI)^b	0.97 (0.90, 1.04)	1.00	0.91 (0.78, 1.06)	0.86 (0.73, 1.02)	0.91 (0.75, 1.10)	0.4193
ER+/PR- ^e
N cases	513	117	136	125	135
HR (95% CI)^a	1.05 (0.96, 1.14)	1.00	1.17 (0.92, 1.50)	1.09 (0.85, 1.40)	1.20 (0.93, 1.53)	0.2780
HR (95% CI)^b	1.05 (0.93, 1.18)	1.00	1.16 (0.89, 1.49)	1.07 (0.81, 1.41)	1.19 (0.86, 1.63)	0.4341
ER-/PR- ^e
N cases	359	98	91	89	81
HR (95% CI)^a	0.95 (0.85, 1.06)	1.00	0.93 (0.70, 1.23)	0.91 (0.68, 1.21)	0.84 (0.62, 1.13)	0.3261
HR (95% CI)^b	0.86 (0.74, 1.00)	1.00	0.84 (0.63, 1.13)	0.77 (0.56, 1.07)	0.65 (0.45, 0.96)	0.0463

^aAge-adjusted models; ^badjusted for age, height, body mass index, energy intake, education, physical activity, smoking status, menopausal status combined with use of menopausal hormone treatment, alcohol intake, age at menarche, use of oral contraceptives, use of progestin, age at menopause, age at first full-term pregnancy and number of live births, breastfeeding, family history of breast cancer, history of personal benign breast disease and mammography; ^cresults for premenopausal breast cancer risk according to hormone receptor status were not presented due to the small number of cases; ^dER-/PR+ postmenopausal invasive breast cancer risk was not analyzed due to small number of cases (n = 73); ^en = 709 postmenopausal invasive breast cancer cases with missing hormone receptor status. HR, hazard ratio.

ISSN: 1465-542X