Table 4.
Odds ratio of breast cancer risk associated with serum levels of PCBs
| Unadjusted | Adjusted | ||||
|---|---|---|---|---|---|
| Continuous (μg/kg lipid) |
Continuous (μg/kg lipid) |
1st Tertile | 2nd Tertile | 3rd Tertile | |
| ∑PCB (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 1.93 (0.84; 4.43) | 2.50 (1.11; 5.63) |
| n (cases/controls) | 76/84 | 76/84 | 14/28 | 27/28 | 35/28 |
| p-value | 0.008 | 0.008 | 0.122 | 0.027 | |
| ∑PCB Grp1 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.01) | 1.00 (reference) | 1.35 (0.60; 3.06) | 2.12 (0.97; 4.16) |
| n (cases/controls) | 76/84 | 76/84 | 17/28 | 23/28 | 36/28 |
| p-value | 0.006 | 0.006 | 0.468 | 0.059 | |
| ∑PCB Grp2 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 2.28 (1.01; 5.18) | 2.14 (0.94; 4.88) |
| n (cases/controls) | 76/84 | 76/84 | 14/28 | 32/28 | 30/28 |
| p-value | 0.029 | 0.029 | 0.048 | 0.069 | |
| ∑PCB Grp3 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 1.63 (0.72; 3.67) | 2.13 (0.96; 4.69) |
| n (cases/controls) | 76/84 | 76/84 | 16/28 | 26/28 | 34/28 |
| p-value | 0.006 | 0.006 | 0.242 | 0.062 | |
| ∑DL-PCB (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.01) | 1.00 (reference) | 1.10 (0.50; 2.41) | 1.52 (0.71; 3.26) |
| n (cases/controls) | 76/84 | 76/84 | 21/28 | 23/28 | 32/28 |
| p-value | 0.057 | 0.057 | 0.821 | 0.277 | |
| PCB99 (OR (95% CI)) | 1.01 | 1.01 (1.00; 1.01) | 1.00 (reference) | 2.85 (1.25; 6.47) | 2.00 (0.86; 4.67) |
| n (cases/controls) | 76/84 | 76/84 | 13/28 | 37/28 | 26/28 |
| p-value | 0.039 | 0.039 | 0.013 | 0.109 | |
| PCB101 (OR (95% CI)) | 1.00 | 1.00 (0.96; 1.05) | 1.00 (reference) | 1.73 (0.80; 3.71) | 1.26 (0.56; 2.81) |
| n (cases/controls) | 76/84 | 76/84 | 19/28 | 34/28 | 23/27 |
| p-value | 0.902 | 0.902 | 0.161 | 0.580 | |
| PCB105 (OR (95% CI)) | 1.01 | 1.01 (0.99; 1.04) | 1.00 (reference) | 1.11 (0.51; 2.41) | 1.54 (0.71; 3.33) |
| n (cases/controls) | 76/84 | 76/84 | 21/28 | 25/30 | 30/26 |
| p-value | 0.217 | 0.217 | 0.790 | 0.274 | |
| PCB118 (OR (95% CI)) | 1.01 | 1.01 (1.00; 1.01) | 1.00 (reference) | 0.83 (0.37; 1.84) | 1.48 (0.70; 3.11) |
| n (cases/controls) | 76/84 | 76/84 | 23/28 | 19/28 | 34/28 |
| p-value | 0.026 | 0.026 | 0.641 | 0.304 | |
| PCB138 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 2.83 (1.22; 6.57) | 2.50 (1.07; 5.85) |
| n (cases/controls) | 76/84 | 76/84 | 12/28 | 34/28 | 30/28 |
| p-value | 0.048 | 0.048 | 0.015 | 0.035 | |
| PCB153 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 2.15 (0.93; 4.99) | 2.69 (1.18; 6.14) |
| n (cases/controls) | 76/84 | 76/84 | 13/28 | 28/28 | 35/28 |
| p-value | 0.005 | 0.005 | 0.074 | 0.019 | |
| PCB156 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.01) | 1.00 (reference) | 1.69 (0.75; 3.80) | 2.06 (0.93; 4.56) |
| n (cases/controls) | 76/84 | 76/84 | 16/28 | 27/28 | 33/28 |
| p-value | 0.250 | 0.250 | 0.206 | 0.074 | |
| PCB170 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.01) | 1.00 (reference) | 2.00 (0.87; 4.58) | 2.43 (1.08; 5.48) |
| n (cases/controls) | 76/84 | 76/84 | 14/28 | 28/28 | 34/28 |
| p-value | 0.022 | 0.022 | 0.101 | 0.033 | |
| PCB180 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.00) | 1.00 (reference) | 0.93 (0.41; 2.08) | 1.65 (0.78; 3.47) |
| n (cases/controls) | 76/84 | 76/84 | 22/29 | 19/27 | 35/28 |
| p-value | 0.012 | 0.012 | 0.855 | 0.189 | |
| PCB183 (OR (95% CI)) | 1.02 | 1.02 (1.00; 1.03) | 1.00 (reference) | 2.46 (1.07; 5.65) | 2.39 (1.04; 5.49) |
| n (cases/controls) | 76/84 | 76/84 | 13/28 | 32/28 | 31/28 |
| p-value | 0.013 | 0.013 | 0.034 | 0.041 | |
| PCB187 (OR (95% CI)) | 1.00 | 1.00 (1.00; 1.01) | 1.00 (reference) | 1.56 (0.69; 3.54) | 2.19 (0.99; 4.82) |
| n (cases/controls) | 76/84 | 76/84 | 16/28 | 25/28 | 35/28 |
| p-value | 0.005 | 0.005 | 0.285 | 0.052 | |
n: number of observations per group; OR: odds ratio; 95% CI: 95% confidence interval; Unadjusted analysis: Only OR, and not 95% CI, were reported for unadjusted data; Adjusted: adjusted for confounders identified by change in estimate, following confounders were considered age, BMI, cotinine levels, parity, and breastfeeding; Bold text: significant finding, OR significantly different from 1; ∑PCB: PCB 99, 101, 105, 118, 128, 138, 153, 156, 170, 180, 183, 187; ∑PCB group 1 (estrogenic PCBs): PCB 101, 187; ∑PCB group 2 (anti-estrogenic and dioxin-like PCBs): PCB 105, 118, 128, 138, 156, 170; ∑PCB group 3 (CYP1A1 and CYP2B inducing PCBs): PCB 99, 153, 180, 183; ∑DL-PCBs (dioxin-like PCBs): PCB 105, 118, 156