Table 1.
Demographic characteristics and selected risk factors for cases and controls
| Characteristic | Cases (n = 413) | Controls (n = 263) |
|---|---|---|
| Male (%) |
36 |
42 |
| Female (%) |
64 |
58 |
| Median age in years1 (median, IQR) |
33 (28–37) |
35 (31–39) |
| European ancestry (%) |
|
|
| British or northern European |
75 |
60 |
| Southern European |
4 |
7 |
| Other European or unknown |
21 |
33 |
|
MC1R (%) |
|
|
| Wild-type consensus alleles only |
15 |
29 |
| r only alleles |
27 |
32 |
| Any R allele |
58 |
40 |
| Number of nevi ≥ 2 mm (median, IQR) |
205 (108–320) |
67 (28–158) |
| Number of dysplastic nevi (%) |
|
|
| 0 |
55 |
76 |
| 1 |
11 |
11 |
| 2+ |
34 |
13 |
| Previous non-melanoma skin cancer (%) |
8 |
2 |
| Confirmed family history of melanoma (%) |
10 |
5 |
| Pigmentation score, self-reported (%) |
|
|
| 1st quartile (lower risk) |
8 |
24 |
| 2nd quartile |
26 |
26 |
| 3rd quartile |
24 |
25 |
| 4th quartile (higher risk) |
42 |
25 |
| Number of childhood blistering sunburns (%) |
|
|
| 0 |
65 |
69 |
| ≤ 8 |
17 |
19 |
| > 8 |
18 |
12 |
| Number of lifetime sunbed sessions (%) |
|
|
| 0 |
76 |
80 |
| 1–10 |
14 |
14 |
| > 10 | 10 | 6 |
IQR interquartile range.
1 Age at diagnosis for cases and age at interview for controls.