Table 3.
Associations between mitochondrial DNA copy number and breast cancer risk
| Stratum | mtDNA copy numbera | Controls | Cases | OR | 95% CI | p value |
|---|---|---|---|---|---|---|
| Overall | Quartile 1 (0.11–0.21) | 132 | 117 | Reference | – | – |
| Quartile 2 (0.21–0.29) | 132 | 148 | 1.48 | (1.00–2.20) | 5.24E-02 | |
| Quartile 3 (0.29–0.47) | 125 | 122 | 1.30 | (0.81–2.11) | 2.77E-01 | |
| Quartile 4 (0.47–1.52) | 133 | 161 | 0.93 | (0.53–1.66) | 8.18E-01 | |
| Continuous variable | 522 | 548 | 0.97 | (0.66–1.42) | 8.75E-01 | |
| ER+ | Quartile 1 (0.11–0.21) | 132 | 68 | Reference | – | – |
| Quartile 2 (0.21–0.29) | 132 | 94 | 1.43 | (0.85–2.39) | 1.77E-01 | |
| Quartile 3 (0.29–0.47) | 125 | 65 | 1.23 | (0.65–2.32) | 5.22E-01 | |
| Quartile 4 (0.47–1.52) | 133 | 18 | 0.46 | (0.18–1.13) | 8.95E-02 | |
| Continuous variable | 522 | 245 | 0.67 | (0.36–1.25) | 2.11E-01 | |
| ER− | Quartile 1 (0.11–0.21) | 132 | 41 | Reference | – | – |
| Quartile 2 (0.21–0.29) | 132 | 42 | 1.33 | (0.74–2.38) | 3.43E-01 | |
| Quartile 3 (0.29–0.47) | 125 | 35 | 0.90 | (0.43–1.91) | 7.91E-01 | |
| Quartile 4 (0.47–1.52) | 133 | 140 | 0.94 | (0.44–2.02) | 8.81E-01 | |
| Continuous variable | 522 | 258 | 1.04 | (0.64–1.69) | 8.79E-01 |
ER Estrogen receptor, mtDNA Mitochondrial DNA
aAnalyses are adjusted for age, body mass index, smoking, center of origin, and plate