Table 1.
SCC Risk Factors among Cases and Controls
| Covariates | SCC n = 415 n (%) | Controls n = 415 n (%) | p value1 |
|---|---|---|---|
| Pigmentation Variables | |||
| Hair color (red/blond)2 | 102 (24.6) | 67 (16.2) | 0.003 |
| Eye color (blue/grey) | 191 (46.1) | 165 (40.0) | 0.073 |
| Skin type3 | |||
| 1 | 58 (14.0) | 20 (4.8) | |
| 2 | 76 (18.3) | 40 (9.6) | |
| 3 | 244 (58.8) | 253 (61.0) | <0.001 |
| 4 | 36 (8.7) | 90 (21.7) | |
| Missing | 1 (0.2) | 12 (2.9) | |
| Childhood freckles (yes) | 224 (54.5) | 111 (27.2) | <0.001 |
|
UV Exposure Variables | |||
| Sunburns (> 2 severe sunburns) | 263 (63.5) | 184 (44.7) | <0.001 |
| Occupational sun exposure4 (yes) | 96 (23.2) | 85 (20.6) | 0.365 |
| Regular peak-time sun exposure5 (yes) | 312 (75.2) | 284 (68.6) | 0.035 |
| Tanning bed use (yes) | 49 (11.8) | 36 (8.7) | 0.137 |
|
Other Variables | |||
| Education (≥ 4-year college degree) | 158 (38.1) | 176(42.5) | 0.193 |
| Cigarette smoking (current) | 29 (7.0) | 16 (3.9) | 0.046 |
| Family history of skin cancer6 | |||
| No | 172 (41.6) | 315 (75.9) | |
| Yes | 136 (32.9) | 59 (14.2) | <0.001 |
| Don’t Know | 106 (25.6) | 41 (9.9) | |
| High-risk exposures7 | 177 (42.7) | 150 (36.1) | 0.055 |
Pearson Chi-squared test for proportions
Ascertained as “adult natural hair color (prior to graying, if applicable)”
Reaction of skin after exposure to 1 hour of mid-day sun for the first time in the summer with 1=painful or blistering sunburn with no tan, 2=painful sunburn followed by a light tan, 3= mild sunburn followed by a moderate tan, 4= no sunburn followed by a deep tan
At least 2 hours/day of sun-exposure between 10am–4 pm for primary occupation
At least 2 hours/day once-a-week of sun-exposure between 10am–4 pm in the past 10 years
Including natural parents, brothers, and sisters only
UV light treatment, burn scar, non-healing ulcers, radiation treatment, arsenic exposure, exposure to industrial chemicals (yes/no)