Table 1. Baseline characteristics of the 31 eligible studies for the analysis of IL-10 polymorphism.
| Studies | Year | Country | Ethnicity | Source of controls | Sample size | SNP studied | Genotyping method | HWE |
| Wu F | 2008 | China | Asian | HB | 61/122 | -1082G/A, -819T/C, -592A/C | PCR-RFLP | 0.379, 0.125, 0.125 |
| Scola A | 2003 | Italy | European | PB | 45/114 | -1082G/A | ARMS-PCR | <0.001 |
| Selvaraj P | 2008 | India | Asian | PB | 155/183 | -1082G/A, -819T/C | PCR-RFLP | 0.204, 0.174 |
| Sharada RS | 2012 | India | Asian | HB | 104/102 | -1082G/A | ARMS-PCR | 0.057 |
| Bellamy R | 1998 | Gambia | African | HB | 401/408 | -1082G/A, -819T/C, -592A/C | PCR-SSP | 0.824, 0.779, 0.779 |
| Oral HB | 2006 | Turkey | European | HB | 81/50 | -1082G/A, -819T/C, -592A/C | PCR-SSP | 0.060, 0.320, 0.320 |
| Ben-Selma W | 2011 | Tunisian | African | HB | 131/95 | -1082G/A, -819T/C, -592A/C | PCR-RFLP | 0.020, 0.957, 0.957 |
| Heno MI | 2006 | Colombia | American | HB | 190/135 | -1082G/A, -819T/C, -592A/C | PCR-SSP | 0.674, 0.410, 0.518 |
| Garcia-Elorriaga G | 2006 | Mexico | American | HB | 77/60 | -1082G/A, -592A/C | Taqman | 0.728, <0.001 |
| Ates O | 2008 | Turkey | Asian | HB | 128/80 | -1082G/A, -819T/C, -592A/C | ARMS-PCR | 0.978, 0.819, 0.819 |
| Delgado JC | 2002 | Cambodian | Asian | HB | 356/106 | -1082G/A, | PCR-RFLP | <0.001 |
| Ulger M | 2013 | Turkey | European | HB | 84/110 | -1082G/A | PCR-RFLP | <0.001 |
| Shin HD | 2005 | Korea | Asian | HB | 449/851 | -1082G/A, -592A/C | MAPA | 0.168, 0.631, |
| Mosaad YM | 2010 | Egypt | African | HB | 110/118 | -1082G/A | ARMS-PCR | <0.001 |
| Oh JH | 2007 | Korea | Asian | HB | 145/117 | -1082G/A | ARMS-PCR | 0.612 |
| Liang L | 2011 | China | Asian | HB | 235/78 | -1082G/A, -819T/C, -592A/C | SNaPshot assay | 0.589, 0.253, 0.253 |
| Ansari A | 2009 | Pakistan | Asian | PB | 178/376 | -1082G/A | ARMS-PCR | <0.001 |
| Thye T | 2009 | Ghana | African | PB | 2010/2346 | -1082G/A, -819T/C, -592A/C | FRET | 0.542, 0.380, 0.551 |
| Ansari A | 2011 | Pakistan | Asian | PB | 102/166 | -1082G/A | ARMS-PCR | <0.001 |
| Lopez-Maderueyo D | 2003 | Spain | European | HB | 113/100 | -1082G/A | ARMS-PCR | 0.949 |
| Meenakshi P | 2013 | India | Asian | HB | 100/100 | -1082G/A | PCR-RFLP | 0.058 |
| Mhmoud N | 2013 | Sudan | Asian | HB | 191/206 | -819T/C, -592A/C | PCR-RFLP | <0.001, <0.001 |
| Mei | 2012 | China | Asian | HB | 169/156 | -592A/C | PCR-RFLP | 0.622 |
| Ma Z | 2007 | China | Asian | HB | 40/40 | -1082G/A | PCR-SSP | 0.292 |
| Yang H | 2010 | China | Asian | HB | 198/200 | -1082G/A | PCR-SSP | 0.253 |
| Liu XX | 2009 | China | Asian | HB | 141/135 | -1082G/A, -819T/C | PCR-RFLP | <0.001, <0.001 |
| Trajkov D | 2009 | Macedonia | European | PB | 75/299 | -1082G/A, -819T/C, -592A/C | PCR-SSP | <0.001, 0.879, 0.403 |
| Fitness J | 2004 | Malawi | African | HB | 210/705 | -1082G/A, -819T/C, -592A/C | ARMS-PCR | 0.524, 0.062, 0.035 |
| Amirzargar AA | 2006 | Iran | Asian | HB | 41/123 | -1082G/A, -819T/C, -592A/C | PCR-SSP | <0.001, 0.671, 0.671 |
| Taype CA | 2010 | Peru | American | HB | 626/513 | -1082G/A, -592A/C | Taqman PCR | 0.142, 0.055 |
| Prabhu Anand S | 2007 | India | Asian | HB | 132/143 | -1082G/A | PCR-RFLP | 0.123 |
PB, population-based controls, HB, hospital-based controls. HWE, Hardy–Weinberg equilibrium. PCR, polymerase chain reaction; SSP, sequence-specific primers; ARMS, amplification refractory mutation system; RFLP, restriction fragment length polymorphism; FRET, fluorescence resonance energy transfer. MAPA, multiplex automated primer extension analysis.