Table 3.
HRs and 95% CIs for colorectal cancer according to cigarette smoking in the Korean Multi-center Cancer Cohort, 1993–2005
| Men | Women | |||||||
|---|---|---|---|---|---|---|---|---|
|
|
|
|||||||
| Number (%) | Person-year | Colorectal cancer case (n) | HR (95% CI)a | Number (%) | Person-year | Colorectal cancer case (n) | HR (95% CI)a | |
| Cigarette smoking history | ||||||||
| Never smoker | 1,486 (19.8) | 16,624.2 | 21 | ref. | 10,018 (90.8) | 118,501.0 | 102 | Ref. |
| Former smoker | 1,714 (22.9) | 16,538.6 | 34 | 1.33 (0.76–2.32) | 208 (1.9) | 2,138.7 | 3 | 1.14 (0.35–3.67) |
| Current smoker | 4,280 (57.2) | 46,733.7 | 57 | 0.97 (0.58–1.62) | 761 (6.9) | 8,618.5 | 3 | 0.30 (0.10–0.97) |
| Missing | 8 (0.1) | 83.3 | 0 | 47 (0.4) | 533.0 | 0 | ||
| Smoking duration (yr) | ||||||||
| Never smoker | 1,486 (19.8) | 16,624.2 | 21 | ref. | 10,018 (90.8) | 118,501.0 | 102 | Ref. |
| < 20 | 1,200 (16.0) | 12,908.6 | 7 | 1.04 (0.43–2.48) | 295 (2.7) | 3,399.0 | 1 | 0.33 (0.05–2.35) |
| 20–39 | 2,259 (30.2) | 24,596.6 | 34 | 1.05 (0.60–1.85) | 340 (3.1) | 3,661.6 | 1 | 0.22 (0.03–1.62) |
| ≥ 40 | 1,606 (21.4) | 14,479.2 | 31 | 1.00 (0.56–1.78) | 162 (1.5) | 1,607.9 | 1 | 0.46 (0.06–3.35) |
| Missing | 937 (12.5) | 11,371.2 | 19 | 1.37 (0.68–2.74) | 219 (2.0) | 2,621.8 | 3 | 0.93 (0.29–2.97) |
| Lifetime cigarette smoking (pack-year) | ||||||||
| Never smoker | 1,486 (19.8) | 16,624.2 | 21 | ref. | 10,018 (90.8) | 118,501.0 | 102 | Ref. |
| < 10 | 841 (11.2) | 8,659.0 | 13 | 2.04 (1.01–4.14) | 360 (3.3) | 3,970.7 | 1 | 0.25 (0.04–1.83) |
| 10–19 | 1,022 (13.6) | 10,542.0 | 8 | 0.76 (0.33–1.74) | 207 (1.9) | 2,223.7 | 1 | 0.38 (0.05–2.77) |
| ≥ 20 | 3,095 (41.3) | 31,567.6 | 49 | 0.95 (0.56–1.60) | 200 (1.8) | 2,179.0 | 1 | 0.38 (0.05–2.76) |
| Missing | 1,044 (13.9) | 12,586.9 | 21 | 1.34 (0.68–2.63) | 249 (2.3) | 2,916.8 | 3 | 0.80 (0.25–2.57) |
HR, Hazard ratio; CI, confidence interval; Ref., reference.
a
Adjusted for body mass index (kg/m2; < 18.5, 18.5–22, 23–24, ≥ 25), moderate physical activity (h/wk; never, 0.5–6, ≥ 7), and alcohol consumption history (never drinker, former drinker, current drinker)