Table 1.
Distribution of Risk Factors for Cutaneous Squamous Cell Carcinomas among Cases and Controls
| Covariates | SCC n = 415 | Controls n = 415 | p value* |
|---|---|---|---|
| Hair color (% red/blond) | 102 (24.6) | 67 (16.2) | 0.003 |
|
| |||
| Eye color (% blue/grey) | 191 (46.1) | 165 (40.0) | 0.073 |
|
| |||
| Skin type⊕ | <0.001 | ||
| 1 | 58 (14.0) | 20 (4.8) | |
| 2 | 76 (18.3) | 40 (9.6) | |
| 3 | 244 (58.8) | 253 (61.0) | |
| 4 | 36 (8.7) | 90 (21.7) | |
| Missing | 1 (0.2) | 12 (2.9) | |
|
| |||
| Education (% 4-year college degree or above) | 158 (38.1) | 176 (42.5) | 0.193 |
|
| |||
| Cigarette smoking (% current) | 29 (7.0) | 16 (3.9) | 0.046 |
|
| |||
| Sunburns (% > 2 severe sunburns) | 263 (63.5) | 184 (44.7) | <0.001 |
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| |||
| Childhood freckles (% yes) | 224 (54.5) | 111 (27.2) | <0.001 |
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| |||
| Occupational sun exposure§ (% yes) | 96 (23.2) | 85 (20.6) | 0.365 |
|
| |||
| Routine sun exposure◇ (% yes) | 312 (75.2) | 284 (68.6) | 0.035 |
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| |||
| Average # hrs/week outdoors 10am–4pm | 0.009 | ||
| 1–2 | 150 (36.2) | 161 (38.8) | |
| 3–5 | 92 (22.2) | 113 (27.2) | |
| 6–10 | 82 (19.8) | 71 (17.1) | |
| >10 | 91 (21.9) | 70 (16.9) | |
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| |||
| Tanning bed use (% yes) | 49 (11.8) | 36 (8.7) | 0.137 |
|
| |||
| History of actinic keratoses¶ (% yes) | 333 (84.1) | 80 (19.9) | <0.001 |
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| |||
| Family history of skin cancer^ | <0.001 | ||
| No | 172 (41.6) | 315 (75.9) | |
| Yes | 136 (32.9) | 59 (14.2) | |
| Don't Know∎ | 106 (25.6) | 41 (9.9) | |
Pearson Chi-squared test for proportions
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
Treatment by a doctor for a precancerous skin lesion
Including natural parents, brothers, and sisters only
More cases than controls reported not knowing their family history of skin cancer. Examination of the survey did not reveals any issues with survey design that would have caused subjects to skip the question differentially. The reasons for the discrepancy are unknown.