Table 3 Main characteristics of the included studies
|  | Studies (%) N = 39 | Melanoma cases (%) n = 7806 | NMSC cases (%) n = 3151 | Controls (%) n = 14875 |
|---|---|---|---|---|
Study design | Â | Â | Â | Â |
Case–control | 21 (54%) | 5092 (65%) | 2052 (65%) | 6852 (46%) |
Case only | 11 (28%) | 2646 (34%) | 0 | 0 |
Control only | 6 (15%) | 0 | 0 | 1464 (10%) |
Cohort | 1 (3%) | 68 (1%) | 1099 (35%) | 6559 (44%) |
Source of controls | Â | Â | Â | Â |
Hospital | 6 (21%) | 509 (10%) | 1169 (37%) | 1847 (12%) |
Population or healthya | 21 (75%) | 4651 (90%) | 1982 (63%) | 12872 (87%) |
Mixed | 1 (4%) | 0 | 0 | 156 (1%) |
Case–control matching b |  |  |  |  |
No | 10 (45%) | 3151 (61%) | 1739 (55%) | 9578 (71%) |
Yes | 12 (55%) | 2009 (39%) | 1412 (45%) | 3833 (29%) |
Phenotype assessment | Â | Â | Â | Â |
Self-administered questionnaire | 16 (41%) | 2768 (35%) | 672 (21%) | 1875 (13%) |
Examination by an expert | 14 (36%) | 3970 (51%) | 1380 (44%) | 4392 (30%) |
Instrumental measure | 2 (5%) | 0 | 0 | 222 (1%) |
Mixed | 5 (13%) | 297 (4%) | 1099 (35%) | 7247 (49%) |
No measure | 2 (5%) | 771 (10%) | 0 | 1139 (8%) |
Genotype assessment | Â | Â | Â | Â |
Sequencing analysis | 26 (67%) | 5942 (76%) | 1059 (34%) | 4813 (32%) |
Othersc | 13 (33%) | 1864 (24%) | 2092 (66%) | 10062 (68%) |
DNA source | Â | Â | Â | Â |
Blood | 24 (62%) | 4645 (60%) | 2743 (87%) | 13304 (89%) |
Buccal cells | 14 (36%) | 3161 (40%) | 408 (13%) | 1326 (9%) |
Tissue | 1 (3%) | 0 | 0 | 245 (2%) |