Table 2.
Risk factors for early and late onset basal cell carcinoma (BCC) compared to controls.
| Early onset (≤ 50 years old) | Late Onset (> 50 years old) | |||||
|---|---|---|---|---|---|---|
| Variable | Controls | Cases | OR (95% CI)a | Controls | Cases | OR (95% CI)1 |
| N (%) | N (%) | N (%) | N (%) | |||
| Sun sensitivity to first solar exposure2 | ||||||
| tan | 59 (12.9) | 26 (3.9) | 1.0 (ref) | 196 (19.6) | 88 (9.8) | 1.0 (ref) |
| mild burn then tan | 218 (47.7) | 290 (43.5) | 3.0 (1.8–4.9) | 505 (50.6) | 437 (48.8) | 1.9 (1.4–2.6) |
| burn then peel | 154 (33.7) | 301 (45.2) | 4.4 (2.6–7.2) | 231 (23.1) | 306 (34.2) | 2.9 (2.1–3.9) |
| burn then blister | 26 (5.7) | 49 (7.4) | 4.2 (2.1–8.1) | 67 (6.7) | 64 (7.2) | 2.1 (1.4–3.2) |
| Number of painful sunburns in childhood3 | ||||||
| None | 203 (47.1) | 218 (36.0) | 1.0 (ref) | 507 (55.5) | 393 (45.7) | 1.0 (ref) |
| 1–3 | 79 (18.3) | 77 (12.7) | 0.9 (0.6–1.3) | 168 (1 8.4) | 139 (16.2) | 1.0 (0.8–1.3) |
| 4–9 | 74 (17.2) | 121 (20.0) | 1.5 (1.1–2.2) | 162 (17.7) | 183 (21.3) | 1.4 (1.1–1.8) |
| ≥ 10 | 75 (17.4) | 190 (31.4) | 2.5 (1.8–3.5) | 76 (8.3) | 145 (16.9) | 2.6 (1.9–3.5) |
| ptrend < 0.0001 | ptrend < 0.0001 | |||||
| Number of blistering sunburns in childhood4 | ||||||
| None | 345(79.9) | 407(66.9) | 1.0 (ref) | 722(78.8) | 593(69.0) | 1.0 (ref) |
| 1 | 49(11.3) | 74(12.2) | 1.3(0.9–1.9) | 84(9.2) | 102(11.9) | 1.4(1.1–2.0) |
| 2–6 | 14(3.2) | 35(5.8) | 2.1(1.1–4.0) | 39(4.3) | 68(7.9) | 2.0(1.4–3.1) |
| ≥ 7 | 24(5.6) | 92(15.1) | 3.3(2.0–5.2) | 71(7.8) | 96(11.2) | 1.7(1.2–2.3) |
| ptrend < 0.0001 | ptrend < 0.013 | |||||
| Recreational sun exposure – proportion of lifetime5 | ||||||
| < 0.495 | 52 (12.1) | 86 (14.3) | 1.0 (ref) | 278 (31.3) | 213 (25.3) | 1.0 (ref) |
| 0.495 to < 0.673 | 99 (23.0) | 115 (19.1) | 0.7 (0.5–1.1) | 228 (25.7) | 197 (23.4) | 1.1 (0.8–1.4) |
| 0.673 to < 0.844 | 144 (33.5) | 185 (30.7) | 0.8 (0.5–1.2) | 186 (21.0) | 200 (23.8) | 1.4 (1.1–1.8) |
| ≥ 0.844 | 135 (31.4) | 217 (36.0) | 1.0 (0.6–1.5) | 195 (22.0) | 231 (27.5) | 1.6 (1.2–2.1) |
| ptrend < 0.0164 | ptrend < 0.0011 | |||||
1
Odd ratios and 95% confidence intervals were estimated by logistic regression and adjusted by study phase, age at diagnosis and gender (male, female).
2
In sun sensitivity to first solar exposure, 11 controls and 9 cases are missing in late onset BCC; 3 controls and 8 cases missing from early onset BCC. These same subjects were missing in all other exposure variables.
3
The number of painful sunburns in child hood was missing in 126 controls and 112 cases.
4
The number of blistering sunburns in childhood was missing in 129 controls and 118 cases.
5
Recreational sun exposure was missing in 153 controls and 134 cases.