Table I.
Selected characteristics among non-hispanic white BCC cases and controls in the Yale Study of Skin Health in Young People (N=766)
| Cases, N=376 | Controls, N=390 | ||
|---|---|---|---|
| Characteristic | N1 (%) | N1 (%) | p-value2 |
| Age (y), median (IQR) | 36.3 (33.2-38.5) | 36.8 (32.8-38.5) | 0.923 |
| Female | 256 (68.1) | 274 (70.3) | 0.515 |
| Body site of skin biopsy | <0.001 | ||
| Head | 204 (54.3) | 164 (42.1) | |
| Extremity | 72 (19.2) | 126 (32.3) | |
| Trunk | 100 (26.6) | 100 (25.6) | |
| Education | 0.012 | ||
| ≤ Some college | 104 (27.7) | 143 (36.9) | |
| College graduate | 113 (30.1) | 116 (29.9) | |
| ≥ Some graduate school | 158 (42.1) | 129 (33.2) | |
| Eye color | <0.001 | ||
| Brown | 86 (22.9) | 154 (39.5) | |
| Hazel | 65 (17.3) | 72 (18.5) | |
| Green | 47 (12.5) | 38 (9.7) | |
| Blue/Grey | 178 (47.3) | 126 (32.3) | |
| Hair color | <0.001 | ||
| Black/Dark brown | 101 (26.9) | 161 (41.3) | |
| Light brown | 135 (36.0) | 155 (39.7) | |
| Blonde/Fair | 100 (26.7) | 63 (16.2) | |
| Red | 39 (10.4) | 11 (2.8) | |
| Skin color (inner upper arm) | <0.001 | ||
| Olive | 15 (4.0) | 77 (19.7) | |
| Fair | 212 (56.4) | 236 (60.5) | |
| Very fair | 149 (39.6) | 77 (19.7) | |
| Skin reaction with first summer sun exposure | <0.001 | ||
| Turn brown, no sunburn | 6 (1.6) | 31 (8.0) | |
| Mild sunburn followed by tan | 142 (37.8) | 200 (51.4) | |
| Painful sunburn peeling | 198 (52.7) | 144 (37.0) | |
| Severe sunburn blistering | 30 (8.0) | 14 (3.6) | |
| Skin reaction with prolonged sun exposure | <0.001 | ||
| Very brown, deeply tanned | 38 (10.1) | 71 (18.2) | |
| Moderately tanned | 169 (44.9) | 223 (57.2) | |
| Mildly tanned peeling tendency | 123 (32.7) | 78 (20.0) | |
| Freckled, no suntan | 46 (12.2) | 18 (4.6) | |
| Moles ≥ 5 mm on back (n), median (IQR) | 1 (0-3) | 0 (0-2) | 0.004 |
| Freckles on face | <0.001 | ||
| None | 78 (20.7) | 139 (35.6) | |
| Very Few | 81 (21.5) | 112 (28.7) | |
| Few | 123 (32.7) | 93 (23.9) | |
| Some | 74 (19.7) | 36 (9.2) | |
| Many | 20 (5.3) | 10 (2.6) | |
| MC1R non-synonymous variants | <0.001 | ||
| 0 variants | 65 (17.3) | 131 (34.2) | |
| 1 variant | 173 (46.1) | 175 (45.7) | |
| ≥ 2 variants | 137 (36.5) | 77 (20.1) | |
| Family history of skin cancer | 246 (65.4) | 153 (29.2) | <0.001 |
| Body mass index (kg/m2) | <0.001 | ||
| <25.0 | 246 (65.4) | 209 (53.6) | |
| 25-29.9 | 90 (23.9) | 106 (27.2) | |
| ≥ 30.0 | 40 (10.6) | 75 (19.2) | |
| Regular use of sunscreen on biopsy site | 76 (20.2) | 43 (11.0) | <0.001 |
| Ever drank alcohol ≥ once/week for ≥6 months | 282 (76.2) | 277 (71.9) | 0.181 |
| Smoking status | <0.001 | ||
| Never | 233 (62.5) | 199 (51.4) | |
| Former | 111 (29.8) | 122 (31.5) | |
| Current | 29 (7.8) | 66 (17.1) | |
| Outdoor sun exposure in warm months (h), mean ± SD | 8938 ± 3426 | 8310 ± 3265 | 0.0103 |
| Outdoor activities (h), median (IQR) | 6825 (3286-11397) | 6260 (3204-11475) | 0.431 |
| Sunburns (n), median (IQR) | 6 (1-16) | 3 (1-9) | <0.001 |
| Sunbathing sessions (n), median (IQR) | 315 (58-713) | 279 (84-689) | 0.622 |
| Employed in outdoor job (months), median (IQR) | 0 (0-12) | 0 (0-10) | 0.265 |
1
May not sum to total due to missing values.
2
χ2 for categorical variables, Wilcoxon Rank Sum for continuous variables.
3
T-test