Table 1.
Associations between each pollutant and breast cancer risk
| NO2 | BaP | PCB153 | ||
|---|---|---|---|---|
| Cases/Controls | OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| Continuous (For each 1SD increase) | 523/523 | 1.04 (0.81, 1.34) | 1.04 (0.81, 1.34) | 1.30 (0.98, 1.73) |
| Quartiles | ||||
| I | 121/131 | 1 (ref) | 1 (ref) | 1 (ref) |
| II | 134/131 | 1.11 (0.74, 1.66) | 1.58 (0.96, 2.61) | 1.19 (0.68, 2.06) |
| III | 132/130 | 1.14 (0.71, 1.83) | 2.03 (1.05, 3.93) | 2.25 (1.13, 4.57) |
| IV | 136/131 | 1.18 (0.66, 2.11) | 2.32 (1.00, 5.37) | 2.07 (0.93, 4.61) |
Conditional logistic regression models were used for estimating ORs and 95%CI, adjusted for body mass index, menopausal hormone replacement therapy uses, urban/rural status at birth, urban/rural status at inclusion, alcohol drinking, breastfeeding, mammography before inclusion, oral contraceptive use, age at full-term pregnancy and parity, smoking status, total physical activity.
The ORs (95% CI) correspond to an increment of 1 SD level in controls, NO2: 17.0 μg/m3, PCB153: 3.92 ng/m3, BaP: 0.126 ng/m3
Quartiles’ cut-offs for NO2 based on the distribution among controls: ≤ 24.2, ≤ 32.4, ≤ 46.5 µg/m3
Quartiles’ cut-offs for PCB153 based on the distribution among controls: ≤ 8.13, ≤ 10.12, ≤ 12.91 ng/m3
Quartiles’ cut-offs for BaP based on the distribution among controls: ≤ 0.133, ≤ 0.179, ≤ 0.240 ng/m3
SD Standard deviation, OR odds ratio, 95% CI 95% confidence intervals, NO2 nitrogen dioxide, BaP: benzo[a]pyrene, PCB153: polychlorinated biphenyls