Table 2.
Individual association of smoking status and polygenic risk score with colorectal cancer risk
| Exposure | Cases, N (%) | Controls, N (%) | Model 1a, OR (95% CI) | Model 2b, OR (95% CI) |
| Smoking status | ||||
| Never | 2,193 (44.5) | 2,057 (50.9) | Ref. | Ref. |
| Former | 1,990 (40.4) | 1,544 (38.2) | 1.25 (1.14–1.37) | 1.26 (1.14–1.40) |
| Current | 745 (15.1) | 440 (10.9) | 1.61 (1.14–1.85) | 1.48 (1.27–1.72) |
| Per 20 pack-years | 1.21 (1.13–1.29) | 1.16 (1.08–1.24) | ||
| PRSc | ||||
| Very low | 214 (4.3) | 405 (10.0) | Ref. | Ref. |
| Low | 499 (10.1) | 613 (15.2) | 1.54 (1.26–1.89) | 1.57 (1.26–1.96) |
| Medium | 2,428 (49.3) | 2,018 (49.9) | 2.28 (1.91–2.72) | 2.40 (1.99–2.91) |
| High | 928 (18.8) | 602 (14.9) | 2.91 (2.40–3.54) | 3.05 (2.47–3.77) |
| Very high | 859 (17.4) | 403 (10.0) | 4.03 (3.29–4.94) | 4.23 (3.40–5.29) |
| Per 20 percentiles | 1.28 (1.24–1.32) | 1.28 (1.24–1.33) |
CI, confidence interval; OR, odds ratio; PRS, polygenic risk score; Ref., reference.
a
Adjusted for age and sex.
b
Additionally adjusted for education, body mass index, physical activity, alcohol consumption, red meat consumption, history of colonoscopy, history of diabetes, family history of colorectal cancer in a first-degree relative, use of statins and use of nonsteroidal anti-inflammatory drugs, PRS (for the analysis of smoking status), and smoking status (for the analysis of PRS).
c
Classification of PRS: very low, ≤10th percentile; low, 11th–25th percentile; medium, 26th–75th percentile; high, 76th–90th percentile; and very high, >90th percentile.