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.