Variables | Low-risk groupa | High-risk groupb | cHRsc, (95Â % CI), P | aHRsd (95Â % CI), P | ||
---|---|---|---|---|---|---|
No. | % | No. | % | Low-risk group (ref.) vs. High-risk group | Low-risk group (ref.) vs. High-risk group | |
 OPC | 575 | 76.5 | 177 | 23.5 |  |  |
  Smoking |  |  |  |  |  |  |
  Ever | 325 | 56.5 | 104 | 58.8 | 1.4 (0.5–3.3), 0.722 | 1.4 (0.6–3.4), 0.787 |
 Never | 250 | 43.5 | 73 | 41.2 | 18.9 (1.3–330.2), 0.032 | 20.0 (1.2–327.0), 0.028 |
 Alcohol |  |  |  |  |  |  |
  Ever | 421 | 73.2 | 128 | 72.3 | 1.3 (0.3–3.7), 0.823 | 1.4 (0.5–3.8), 0.822 |
  Never | 154 | 26.8 | 49 | 27.7 | 1.9 (0.3–17.2), 0.887 | 1.8 (0.2–16.1), 0.867 |
Non-OPC | 614 | 79.0 | 163 | 21.0 | Â | Â |
 Smoking |  |  |  |  |  |  |
  Ever | 455 | 74.1 | 125 | 76.7 | 2.1 (1.1–4.2), 0.013 | 2.3 (1.2–4.4), 0.011 |
  Never | 159 | 25.9 | 38 | 23.3 | 0.2 (0.1–1.4), 0.346 | 0.1 (0.0–1.2), 0.323 |
  Alcohol |  |  |  |  |  |  |
  Ever | 426 | 69.4 | 124 | 76.1 | 2.3 (1.1–3.9), 0.022 | 2.2 (1.2–4.1), 0.019 |
  Never | 188 | 30.6 | 39 | 23.9 | 0.5 (0.2–4.3), 0.798 | 0.6 (0.1–4.1), 0.801 |