Table 2. Baseline characteristics of study population.
| N (%) | Total population (n = 1,859) |
Never cigarette smokers (n = 323) | Former cigarette smokers (n = 870) | Current cigarette smokers (n = 630) | Unknown smoking status (n = 36) |
p value1 |
|---|---|---|---|---|---|---|
| Age at diagnosis (mean ± SD) | 62.4 ±9.7 | 61.5±11.3 | 65.1±8.3 | 59.0±9.5 | 66.9±8.3 | <0.001 |
| Gender | <0.001 | |||||
| Male | 1,507 (81.1) | 215 (66.6) | 757 (87.0) | 503 (79.8) | 32 (88.9) | |
| Female | 352 (18.9) | 108 (33.4) | 113 (13.0) | 127 (20.2) | 4 (11.1) | |
| Type of tobacco | <0.001 | |||||
| Ever cigar and/or pipe smoker | 369 (20.2) | 109 (33.7) | 170 (19.6) | 85 (13.5) | 5 (71.4) | |
| Never cigar and/or pipe smoker | 1458 (79.8) | 214 (66.3) | 697 (80.4) | 545 (86.5) | 2 (28.6) | |
| Missing | 32 | 0 | 3 | 0 | 29 | |
| Tumor stage | 0.036 | |||||
| 0a | 1,052 (57.4) | 187 (59.0) | 489 (57.1) | 359 (57.7) | 17 (47.2) | |
| 0is | 59 (3.2) | 13 (4.1) | 27 (3.2) | 16 (2.6) | 3 (8.3) | |
| I | 400 (21.8) | 68 (21.5) | 208 (24.3) | 117 (18.8) | 7 (19.4) | |
| II/III/IV | 322 (17.6) | 49 (15.5) | 134 (15.6) | 130 (20.9) | 9 (25.0) | |
| Missing | 26 | 6 | 12 | 8 | 0 | |
| Concomitant CIS | 0.341 | |||||
| No | 1614 (88.1) | 284 (89.3) | 744 (87.0) | 555 (89.2) | 31 (86.1) | |
| Yes | 217 (11.9) | 34 (10.7) | 111 (13.0) | 67 (10.8) | 5 (13.9) | |
| Missing | 28 | 5 | 15 | 8 | 0 | |
| Tumor grade2 | 0.074 | |||||
| Low-grade | 979 (54.1) | 173 (55.4) | 438 (51.4) | 350 (57.3) | 18 (52.9) | |
| High-grade | 830 (45.9) | 139 (44.6) | 414 (48.6) | 261 (42.7) | 16 (47.1) | |
| Missing | 50 | 11 | 18 | 19 | 2 | |
| Tumor number | 0.256 | |||||
| Single | 1,030 (59.7) | 179 (60.9) | 466 (57.6) | 364 (61.8) | 21 (65.6) | |
| Multiple | 694 (40.3) | 115 (39.1) | 343 (42.4) | 225 (38.2) | 11 (34.4) | |
| Missing | 135 | 29 | 61 | 41 | 4 | |
| Tumor size | 0.379 | |||||
| < 3cm | 377 (75.1) | 60 (73.2) | 171 (72.8) | 139 (78.5) | 7 (87.5) | |
| ≥ 3cm | 125 (24.9) | 22 (26.8) | 64 (27.2) | 38 (21.5) | 1 (12.5) | |
| Missing | 1,357 | 241 | 635 | 453 | 28 | |
| Histological type | 0.126 | |||||
| UCC | 1,808(97.8) | 310 (96.9) | 848 (98.1) | 616 (98.1) | 34 (94.4) | |
| SCC | 17 (0.9) | 5 (1.6) | 7 (0.8) | 5 (0.8) | 0 (-) | |
| AC | 9 (0.5) | 4 (1.2) | 1 (0.1) | 3 (0.5) | 1 (2.8) | |
| Other | 14 (0.8) | 1 (0.3) | 8 (0.9) | 4 (0.6) | 1 (2.8) | |
| Missing | 11 | 3 | 6 | 2 | 0 |
1 P value is based on chi-square, Fisher exact, or one-way ANOVA test, where appropriate.
2 Tumors with WHO 1973 differentiation grade 1 or 2, WHO/ISUP 2004 low grade, or Malmström (Modified Bergkvist) grade 1 or 2a were considered low-grade tumors. Tumors with WHO 1973 differentiation grade 3, WHO/ISUP 2004 high grade, or Malmström (Modified Bergkvist) grade 2b or 3 as high-grade
Missing data were not included in the calculation of p values. Abbreviations: N: number of patients; SD: standard deviation; CIS: carcinoma in situ; UCC: urothelial cell carcinoma; SCC: Squamous cell carcinoma; AC: Adenocarcinoma.