Table 1. Characteristics of the individual studies for PsA included in the meta-analysis.
| First author | Year | Country/Ethnicity | Type of psoriasis | SNPs:case/control (n) | HWE | NOS score | |||||
| 308A/G | 238A/G | 857T/C | 1031C/T | 863A/G | 488A/G | ||||||
| Giardina-G | 2011 | Germany/Caucasian | PsA | - | - | 370/560 | - | - | - | Y | 7 |
| Giardina-I | 2011 | Italy/Caucasian | PsA | - | - | 400/400 | - | - | - | Y | 7 |
| Giardina-U | 2011 | UK/Caucasian | PsA | - | - | 125/354 | - | - | - | Y | 7 |
| Popa | 2011 | Romania/Caucasian | PsA | 86/142 | 86/147 | 86/142 | - | - | - | Y | 7 |
| Reich1 | 2007 | Germany/Caucasian | PsA | 361/370 | 368/372 | 370/373 | 367/368 | - | - | Y | 7 |
| Rahman-N | 2005 | Newfoundland/Caucasian | PsA | 225/103 | 228/103 | 220/103 | 220/103 | 231/103 | - | Y | 7 |
| Rahman-T | 2005 | Toronto/Caucasian | PsA | 203/101 | 199/101 | 199/101 | 200/99 | 200/101 | - | Y | 7 |
| Balding | 2003 | Ireland/Caucasian | PsA | 149/390 | - | - | - | - | - | N | 6 |
| Gonzalez-S | 2002 | Spain/Caucasian | PsA | 81/110 | 81/110 | - | - | - | - | N | 8 |
| Al-Heresh | 2002 | Ireland/Caucasian | PsA | 124/101 | 124/101 | - | - | - | 124/101 | N | 8 |
| Hohler-1 | 2002 | Germany/Caucasian | PsA | 87/99 | 87/99 | - | - | - | - | Y | 7 |
| Gonzalez-J | 2001 | Jewish/Caucasoid | PsA | 52/73 | 52/73 | - | - | - | - | N | 8 |
| Hamamoto | 2000 | Japan/Asian | PsA | 20/87 | 20/87 | 20/87 | 20/87 | 20/87 | - | N | 8 |
| Hohler-2 | 1997 | Germany/Caucasian | PsA | 62/99 | 62/99 | - | - | - | - | Y | 7 |
Notes: “PsA”, psoriatic arthritis; “SNPs”, single nucleotide polymorphisms; “HWE”, Hardy–Weinberg equilibrium; “NOS”, Newcastle-Ottawa Scale; “Y”, yes, consistency tests of HWE were performed; “N”, no, consistency tests of HWE were not performed. “-”, no statistics.