Table 1. Characteristics of the studies included in the meta-analysis.
| Study | Year | Ethnicity | Diagnostic criteria | Study design | No. of cases | No. of controls | MAF in cases/controls | Genotyping method | P HWE |
| Sakura [15] | 1996 | Caucasian | T2D patients | Population based-study | 133 | 82 | 0.30/0.30 | PCR-SSCP | 0.05 |
| Inoue [16] | 1997 | Caucasian | T2D patients | Population based-study | 291 | 164 | 0.34/0.34 | PCR-RFLP | >0.05 |
| Hani [17] | 1998 | Caucasian | T2D patients | Population based-study | 191 | 114 | 0.49/0.37 | PCR-SSCP | 0.95 |
| Altshuler [18] | 2000 | Caucasian | T2D per WHO criteria | Family based-study | 333 trios | / | / | SBE-FRET, SBE-FP | / |
| Yamada [19] | 2001 | East Asian | T2D per WHO criteria | Population based-study | 103 | 73 | 0.39/0.34 | PCR-SSCP | 0.20 |
| Gloyn [20] | 2001 | Caucasian | T2D patients | Population based-study | 360 | 307 | 0.40/0.36 | PCR-SSCP | 0.09 |
| Florez [21] | 2004 | Caucasian | T2D per WHO criteria | Population based-study | 1077 | 1077 | 0.47/0.61 | Flight mass spectroscopy | 0.71 |
| Barroso [22] | 2003 | Caucasian | T2D patients | Population based-study | 499 | 494 | 0.38/0.34 | FP-TDI | 0.82 |
| Gloyn [23] | 2003 | Caucasian | T2D per WHO criteria | Population based-study, Family based-study | 854, 150 trios | 1182 | 0.41/0.34 | PCR-RFLP | 0.53 |
| Hansen [24] | 2005 | Caucasian | T2D per WHO criteria | Population based-study | 1164 | 4733 | 0.40/0.36 | PCR-RFLP, LNA | 0.52 |
| van Dam [25] | 2005 | Caucasian | T2D per WHO criteria | Population based-study | 323 | 296 | 0.41/0.36 | PCR-RFLP | 0.56 |
| Yokoi [26] | 2006 | East Asian | T2D per WHO criteria | Population based-study | 1590 | 1244 | 0.38/0.37 | MassARRAY | 0.64 |
| Liu [27] | 2006 | East Asian | T2D per WHO criteria | Population based-study | 502 | 501 | 0.43/0.38 | Sequencing | >0.05 |
| Weedon [28] | 2006 | Caucasian | T2D per WHO criteria | Population based-study | 2332 | 3592 | 0.38/0.35 | TaqMan | >0.05 |
| Sale [29] | 2007 | Other | T2D patients | Population based-study | 572 | 587 | 0.06/0.07 | MassARRAY | 0.22 |
| Koo [30] | 2007 | East Asian | T2D per WHO criteria | Population based-study | 758 | 630 | 0.44/0.38 | TaqMan | 0.05 |
| Sakamoto [31] | 2007 | East Asian | T2D per WHO criteria | Population based-study | 906 | 889 | 0.39/0.34 | TaqMan | 0.72 |
| Saxena [32] | 2007 | Caucasian | T2D per WHO criteria | Population based-study | 5065 | 5785 | 0.49/0.47 | Affymetrix GeneChip, MassARRAY | >0.05 |
| Vaxillaire [33] | 2007 | Caucasian | T2D per ADA criteria | Population based-study | 287 | 2684 | 0.41/0.39 | TaqMan | 0.68 |
| Scott [34] | 2007 | Caucasian | T2D per WHO criteria | Population based-study | 2295 | 2363 | 0.49/0.46 | Illumina GeneChip, MassARRAY | 0.72 |
| Willer [35] | 2007 | Caucasian | T2D per WHO criteria | Population based-study | 1087 | 953 | 0.49/0.44 | MassARRAY | 0.32 |
| Qi [36] | 2007 | Caucasian | T2D patients | Population based-study | 682 | 1078 | 0.40/0.35 | TaqMan | 0.38 |
| Cejková [37] | 2007 | Caucasian | T2D per WHO criteria | Population based-study | 172 | 113 | 0.37/0.37 | PCR-RFLP | 0.26 |
| Doi [38] | 2007 | East Asian | T2D per WHO criteria | Population based-study | 550 | 2322 | 0.39/0.34 | TaqMan | 0.46 |
| Lyssenko [39] | 2008 | Caucasian | T2D per WHO criteria | Population based-study | 2201 | 16034 | 0.41/0.40 | TaqMan | >0.05 |
| Alsmadi [40] | 2008 | Other | T2D per ADA criteria | Population based-study | 550 | 335 | 0.21/0.14 | TaqMan | 0.40 |
| Takeuchi [41] | 2008 | East Asian | T2D per WHO criteria | Population based-study | 7954 | 8809 | 0.38/0.35 | Illumina GeneChip, MassARRAY, TaqMan | 0.91 |
| Peng [42] | 2008 | East Asian | T2D per ADA criteria | Population based-study | 275 | 168 | 0.69/0.57 | PCR-RFLP | >0.05 |
| Bronstein [43] | 2008 | Other | T2D patients | Population based-study | 1131 | 1147 | 0.36/0.61 | KASPar | 0.58 |
| Sanghera [44] | 2008 | Indian | T2D per ADA criteria | Population based-study | 532 | 374 | 0.34/0.38 | TaqMan | 0.45 |
| Cauchi [45] | 2008 | Caucasian | T2D per WHO criteria | Population based-study | 2734 | 4234 | 0.37/0.37 | TaqMan | 0.69 |
| Ezzidi [46] | 2009 | Other | T2D per ADA criteria | Population based-study | 805 | 503 | 0.32/0.29 | TaqMan | 0.56 |
| Zhou [47] | 2009 | East Asian | T2D per WHO criteria | Population based-study | 1848 | 1910 | 0.41/0.39 | TaqMan | 0.39 |
| Chistiakov [48] | 2009 | Caucasian | T2D per WHO criteria | Population based-study | 129 | 117 | 0.50/0.39 | PCR-RFLP | >0.05 |
| Wang [49] | 2009 | East Asian | T2D per WHO criteria | Population based-study | 396 | 387 | 0.46/0.37 | SNapShot | 0.46 |
| Tabara [50] | 2009 | East Asian | T2D per ADA criteria | Population based-study | 484 | 397 | 0.41/0.37 | TaqMan | 0.30 |
| Thorsby [51] | 2009 | Caucasian | T2D patients | Population based-study | 750 | 1879 | 0.41/0.41 | PCR-RFLP | 0.18 |
| Hu [52] | 2009 | East Asian | T2D per WHO criteria | Population based-study | 1849 | 1785 | 0.42/0.39 | MassARRAY | >0.05 |
| Yamauchi [53] | 2010 | East Asian | T2D per WHO criteria | Population based-study | 4470 | 3071 | 0.38/0.37 | Illumina GeneChip | >0.05 |
| Neuman [54] | 2010 | Other | T2D patients | Population based-study | 573 | 843 | 0.37/0.36 | Pyrosequencing | 0.22 |
| Chauhan [55] | 2010 | Indian | T2D per WHO criteria | Population based-study | 2434 | 2403 | 0.39/0.32 | Golden Gate assay | 0.41 |
| Gupta [56] | 2010 | Indian | T2D per WHO criteria | Population based-study | 209 | 179 | 0.40/0.47 | Sequencing | 0.12 |
| Wen [57] | 2010 | East Asian | T2D per WHO criteria | Population based-study | 1165 | 1135 | 0.41/0.40 | MassARRAY | 0.10 |
| Rees [58] | 2011 | Indian | T2D per WHO criteria | Population based-study | 1663 | 1567 | 0.38/0.38 | TaqMan | 0.13 |
| Chavali [59] | 2011 | Indian | T2D per WHO criteria | Population based-study | 1017 | 1006 | 0.39/0.35 | Golden Gate assay | >0.05 |
| Cheung [60] | 2011 | Chinese | T2D per WHO criteria | Population based-study | 198 | 1185 | 0.33/0.33 | TaqMan | 0.41 |
| Gamboa-Meléndez [61] | 2012 | Other | T2D per ADA criteria | Population based-study | 1027 | 990 | 0.40/0.37 | KASPAR | >0.05 |
| Gonen [62] | 2012 | Other | T2D per ADA criteria | Population based-study | 162 | 79 | 0.34/0.30 | PCR-SSCP | NA |
WHO: World health organization, ADA: American diabetes association, MAF: minor allele frequency, LNA: locked nucleic acid assay, FP-TDI: fluorescence polarization template-directed incorporation. SBE-FRET: single-base extension with fluorescence resonance energy transfer; SBE-FP: single-base extension with fluorescence polarization.