Table 1. Descriptive characteristics of the BCPP sample for GxE with smoking analysis.
| Characteristics | Never smokers (N=72) | Ever smokers (N=474) | P value* |
|---|---|---|---|
| Tumor size (cm), mean (SD) (N=533) | 2.69 (2.14) | 2.48 (1.86) | 0.4 |
| Gender (N=546) | 0.002 | ||
| Males (%) | 46 (10.8) | 381 (89.2) | |
| Females (%) | 26 (21.8) | 93 (78.2) | |
| Age (years), mean (SD) (N=546) | 72.2 (10.9) | 69.7 (10.2) | 0.07 |
| Grade (N=539) | 0.7 | ||
| G3 (%) | 49 (13.6) | 312 (86.4) | |
| G2 and G1 (%) | 22 (12.4) | 156 (87.6) | |
| Tumor stage (N=546) | 0.6 | ||
| Ta and Tis (%) | 47 (12.6) | 326 (87.4) | |
| T1 (%) | 25 (14.5) | 148 (85.5) | |
| Cigarettes smoked/day, mean (SD) (N=322) | N/A | 15.8 (12.9) | N/A |
*, P value was calculated with chi-square test for categorical variables and t-test for continuous outcomes. BCPP, Bladder Cancer Prognosis Programme; GxE, gene-environment interaction.