Characteristics of the study population
| Cases | Controls | |
| Number | 418 | 3423 |
| Sex | ||
| Male:female | 140:278 | 1584:1839 |
| Age | ||
| Mean (range) | 47 (15–87) | 57 (30–98) |
| No. of primary melanomas in case | ||
| One (%) | 338 (81) | – |
| Two (%) | 61 (15) | – |
| Three or more (%) | 19 (4) | – |
| No. of first-degree or second-degree relatives with melanoma | ||
| None (%)* | 16 (4) | – |
| One (%) | 226 (54) | – |
| Two (%) | 144 (34) | – |
| Three or more (%) | 32 (8) | – |
*These cases had one or more third-degree relative(s) with melanoma.