Table 1.
Distribution of selected baseline characteristics among cutaneous squamous cell carcinoma (SCC) cases and controls from the Skin Cancer Prevention Study (n=342).a
| Characteristic | SCC Cases (n=113), No. (%) |
Controls (n=229), No. (%) |
|---|---|---|
| Gender | ||
| Male | 100 (88.5) | 201 (87.8) |
| Female | 13 (11.5) | 28 (12.2) |
| Median age, SD (years) | 68 (8.0) | 67 (8.2) |
| Randomization arm in RCT | ||
| Treatment | 66 (58.4) | 115 (50.2) |
| Placebo | 47 (41.6) | 114 (49.8) |
| Study centerb | ||
| DHMC | 24 (21.2) | 43 (18.8) |
| UCLA | 32 (28.3) | 65 (28.4) |
| UCSF | 25 (22.1) | 56 (24.4) |
| UMN | 32 (28.3) | 65 (28.4) |
| Previous skin cancers | ||
| 1 | 24 (21.2) | 102 (44.5)*** |
| 2 | 21 (18.6) | 41 (17.9) |
| 3 | 12 (10.6) | 20 (8.7) |
| 4–5 | 26 (23.0) | 36 (15.7) |
| 6–9 | 12 (10.6) | 17 (7.4) |
| ≥10 | 18 (15.9) | 11 (4.8) |
| Cigarette use | ||
| Never smoked | 28 (24.8) | 91 (39.7)** |
| Former smoker | 62 (54.9) | 111 (48.5) |
| Current smoker | 23 (20.3) | 27 (11.8) |
| Body mass index (kg/m2) | ||
| Underweight <18.5 | 1 (0.9) | 2 (0.8) |
| Normal 18.5–24.9 | 50 (44.2) | 98 (42.8) |
| Overweight 45.0–29.9 | 47 (41.6) | 108 (47.2) |
| Obese >30.0 | 12 (10.6) | 15 (6.6) |
| Skin sun sensitivity | ||
| Always or usually burns | 72 (63.7) | 110 (48.0)** |
| Burns moderately or minimally | 41 (36.3) | 118 (51.5) |
| Extent of UV skin damage | ||
| Mild | 9 (8.0) | 62 (27.1)*** |
| Moderate | 71 (62.8) | 134 (58.5) |
| Severe | 32 (28.3) | 31 (13.5) |
| Sun bathed (hours) | ||
| Never | 40 (35.4) | 62 (27.1) |
| 0–200 | 18 (15.9) | 63 (27.5) |
| 200–400 | 25 (22.1) | 54 (23.6) |
| 400–600 | 21 (18.6) | 33 (14.4) |
| >600 | 7 (6.2) | 17 (7.4) |
| Occupational sun exposure (years) | ||
| 0–7 | 41 (36.3) | 78 (34.1) |
| 7–20 | 31 (27.4) | 64 (27.9) |
| 21–40 | 28 (24.8) | 40 (17.5) |
| >40 | 13 (11.5) | 46 (20.1) |
| Eye color | ||
| Blue, green, gray, hazel | 97 (85.8) | 185 (80.8) |
| Brown, black | 16 (14.2) | 44 (19.2) |
| Hair color | ||
| Blonde, red | 49 (43.4) | 61 (26.6)** |
| Brown, black | 64 (56.6) | 64 (27.9) |
| Vitamin use | ||
| No | 67 (59.3) | 128 (55.9) |
| Occasional | 15 (13.3) | 37 (16.2) |
| Daily | 24 (21.2) | 60 (26.2) |
P< 0.05,
P < 0.01,
P < 0.001. P values obtained from X2, Fisher’s exact, or Wilcoxon rank sum test (as appropriate) comparing sociodemographic and skin cancer risk factors between SCC cases and controls.
Numbers may not sum to the overall total due to missing data.
This multicenter study was conducted at sites in California (University of California at Los Angeles School of Medicine (UCLA); University of California Medical School, San Francisco (UCSF)), Minnesota (University of Minnesota Schools of Medicine and Public Health, Minneapolis (UMN)), and New Hampshire (Dartmouth-Hitchcock Medical Center, Hanover (DHMC)), USA.