Table 1.

Distribution of selected baseline characteristics among cutaneous SCC cases and controls from the Skin Cancer Prevention Study (n = 342)a

CharacteristicSCC cases (n = 113), n (%)Controls (n = 229), n (%)
Gender
 Male100 (88.5)201 (87.8)
 Female13 (11.5)28 (12.2)
Median age, SD (years)68 (8.0)67 (8.2)
Randomization arm in RCT
 Treatment66 (58.4)115 (50.2)
 Placebo47 (41.6)114 (49.8)
Study centerb
 DHMC24 (21.2)43 (18.8)
 UCLA32 (28.3)65 (28.4)
 UCSF25 (22.1)56 (24.4)
 UMN32 (28.3)65 (28.4)
Previous skin cancers
 124 (21.2)102 (44.5)c
 221 (18.6)41 (17.9)
 312 (10.6)20 (8.7)
 4–526 (23.0)36 (15.7)
 6–912 (10.6)17 (7.4)
 ≥1018 (15.9)11 (4.8)
Cigarette use
 Never smoked28 (24.8)91 (39.7)d
 Former smoker62 (54.9)111 (48.5)
 Current smoker23 (20.3)27 (11.8)
Body mass index (kg/m2)
 Underweight <18.51 (0.9)2 (0.8)
 Normal 18.5–24.950 (44.2)98 (42.8)
 Overweight 25.0–29.947 (41.6)108 (47.2)
 Obese >30.012 (10.6)15 (6.6)
Skin sun sensitivity
 Always or usually burns72 (63.7)110 (48.0)d
 Burns moderately or minimally41 (36.3)118 (51.5)
Extent of UV skin damage
 Mild9 (8.0)62 (27.1)c
 Moderate71 (62.8)134 (58.5)
 Severe32 (28.3)31 (13.5)
Sun bathed (hours)
 Never40 (35.4)62 (27.1)
 0–20018 (15.9)63 (27.5)
 200–40025 (22.1)54 (23.6)
 400–60021 (18.6)33 (14.4)
 >6007 (6.2)17 (7.4)
Occupational sun exposure (years)
 0–741 (36.3)78 (34.1)
 7–2031 (27.4)64 (27.9)
 21–4028 (24.8)40 (17.5)
 >4013 (11.5)46 (20.1)
Eye color
 Blue, green, gray, hazel97 (85.8)185 (80.8)
 Brown, black16 (14.2)44 (19.2)
Hair color
 Blonde, red49 (43.4)61 (26.6)d
 Brown, black64 (56.6)64 (27.9)
Vitamin use
 No67 (59.3)128 (55.9)
 Occasional15 (13.3)37 (16.2)
 Daily24 (21.2)60 (26.2)
  • NOTE: P values obtained from χ2, Fisher's exact, or Wilcoxon rank sum test (as appropriate) comparing sociodemographic and skin cancer risk factors between SCC cases and controls.

  • Abbreviations: DHMC, Dartmouth-Hitchcock Medical Center; RCT, randomized control trial; UCLA, University of California at Los Angeles School of Medicine; UCSF, University of California Medical School; UMN, University of Minnesota Schools of Medicine and Public Health.

  • aNumbers may not sum to the overall total due to missing data.

  • bThis multicenter study was conducted at sites in California [UCLA (Los Angeles) and UCSF (San Francisco)], Minnesota [UMN (Minneapolis)], and New Hampshire [DHMC (Lebanon)].

  • cP < 0.001.

  • dP < 0.01.