Table 4. Summary of the subgroup analyses in this meta-analysis.
| Comparison | Category | Category | Studies | OR (95% CI) | P-value |
|---|---|---|---|---|---|
| G vs A | Ethnicity | Asians | 7 | 1.34(1.07, 1.69) | 0.012 |
| Caucasians | 4 | 1.21(1.13, 1.29) | <0.001 | ||
| SOC | HB | 6 | 1.13(0.99, 1.28) | 0.053 | |
| PB | 5 | 1.49(1.22, 1.81) | <0.001 | ||
| Type | Knee OA | 6 | 1.16(0.99, 1.35) | 0.054 | |
| TMJOA | 1 | 1.57(1.09, 2.26) | 0.015 | ||
| Hand OA | 1 | 1.94(1.39, 2.71) | <0.001 | ||
| Hip OA | 3 | 1.30(1.10, 1.55) | 0.002 | ||
| HWE | Yes | 1 | 1.22(1.01, 1.46) | 0.037 | |
| No | 10 | 1.27(1.12, 1.44) | <0.001 | ||
| Genotype methods | PCR-RFLP | 4 | 1.40(0.99, 1.98) | 0.056 | |
| PCR | 1 | 1.57(1.09, 2.26) | 0.015 | ||
| KASPar chemistry | 4 | 1.21(1.13, 1.29) | <0.001 | ||
| Taqman | 1 | 1.53(1.28, 1.82) | <0.001 | ||
| MALDI-TOF MS | 1 | 0.90(0.74, 1.11) | 0.335 | ||
| Study quality | Medium | 8 | 1.25(1.11, 1.41) | <0.001 | |
| High | 3 | 1.28(0.87, 1.88) | 0.025 | ||
| GG vs AA | Ethnicity | Asians | 7 | 1.44(0.99, 2.09) | 0.059 |
| Caucasians | 4 | 1.46(1.28, 1.67) | <0.001 | ||
| SOC | HB | 6 | 1.28(0.99, 1.65) | 0.055 | |
| PB | 5 | 1.56(1.24, 1.96) | <0.001 | ||
| Type | Knee OA | 6 | 1.26(0.98, 1.63) | 0.074 | |
| TMJOA | 1 | 2.84(1.31, 6.14) | 0.008 | ||
| Hand OA | 1 | 2.58(1.15, 5.77) | 0.021 | ||
| Hip OA | 3 | 1.43(1.16, 1.76) | 0.001 | ||
| HWE | Yes | 1 | 1.45(1.04, 2.01) | 0.030 | |
| No | 10 | 1.39(1.12, 1.72) | 0.002 | ||
| Genotype methods | PCR-RFLP | 4 | 1.53(0.93, 2.54) | 0.097 | |
| PCR | 1 | 2.84(1.31, 6.14) | 0.008 | ||
| KASPar chemistry | 4 | 1.46(1.28, 1.67) | <0.001 | ||
| Taqman | 1 | 1.29(0.59, 2.79) | 0.520 | ||
| MALDI-TOF MS | 1 | 0.81(0.54, 1.22) | 0.318 | ||
| Study quality | Medium | 8 | 1.42(1.19, 1.68) | <0.001 | |
| High | 3 | 1.36(0.62, 2.88) | 0.416 | ||
| GG + GA vs AA | Ethnicity | Asians | 7 | 1.42(0.91, 2.22) | 0.119 |
| Caucasians | 4 | 1.30(1.16, 1.46) | <0.001 | ||
| SOC | HB | 6 | 1.10(0.92, 1.30) | 0.304 | |
| PB | 5 | 1.88(1.09, 3.25) | 0.023 | ||
| Type | Knee OA | 6 | 1.23(0.92, 1.64) | 0.164 | |
| TMJOA | 1 | 1.44(0.83, 2.49) | 0.198 | ||
| Hand OA | 1 | 3.70(2.20, 6.21) | <0.001 | ||
| Hip OA | 3 | 1.26(1.06, 1.51) | 0.011 | ||
| HWE | Yes | 1 | 0.91(0.69, 1.19) | 0.495 | |
| No | 10 | 1.41(1.11, 1.79) | 0.005 | ||
| Genotype methods | PCR-RFLP | 4 | 1.81(0.89, 3.66) | 0.101 | |
| PCR | 1 | 1.44(0.83, 2.49) | 0.198 | ||
| KASPar chemistry | 4 | 1.30(1.16, 1.46) | <0.001 | ||
| Taqman | 1 | 0.92(0.43, 1.99) | 0.841 | ||
| MALDI-TOF MS | 1 | 0.83(0.59, 1.18) | 0.304 | ||
| Study quality | Medium | 8 | 1.46(1.12, 1.89) | 0.005 | |
| High | 3 | 0.99(0.71, 1.40) | 0.975 | ||
| GG vs GA + AA | Ethnicity | Asians | 7 | 1.37(0.97, 1.92) | 0.071 |
| Caucasians | 4 | 1.27(1.15, 1.41) | <0.001 | ||
| SOC | HB | 6 | 1.27(1.01, 1.59) | 0.037 | |
| PB | 5 | 1.41(1.09, 1.83) | 0.010 | ||
| Type | Knee OA | 6 | 1.19(0.97, 1.47) | 0.102 | |
| TMJOA | 1 | 2.64(1.34, 5.22) | 0.005 | ||
| Hand OA | 1 | 1.14(0.55, 2.34) | 0.729 | ||
| Hip OA | 3 | 1.48(1.07, 2.03) | 0.016 | ||
| HWE | Yes | 1 | 1.82(1.35, 2.44) | <0.001 | |
| No | 10 | 1.27(1.07, 1.51) | 0.007 | ||
| Genotype methods | PCR-RFLP | 4 | 1.21(0.76, 1.90) | 0.420 | |
| PCR | 1 | 2.64(1.34, 5.22) | 0.005 | ||
| KASPar chemistry | 4 | 1.27(1.15, 1.41) | <0.001 | ||
| Taqman | 1 | 1.93(1.56, 2.40) | <0.001 | ||
| MALDI-TOF MS | 1 | 0.91(0.66, 1.26) | 0.568 | ||
| Study quality | Medium | 8 | 1.25(1.09, 1.44) | 0.001 | |
| High | 3 | 1.60(0.88, 2.92) | 0.122 | ||
| GA vs AA | Ethnicity | Asians | 7 | 1.30(0.76, 2.21) | 0.335 |
| Caucasians | 4 | 1.21(1.07, 1.37) | 0.002 | ||
| SOC | HB | 6 | 0.99(0.80, 1.22) | 0.898 | |
| PB | 5 | 1.78(0.94, 3.39) | 0.078 | ||
| Type | Knee OA | 6 | 1.16(0.82, 1.65) | 0.391 | |
| TMJOA | 1 | 1.12(0.63, 2.01) | 0.698 | ||
| Hand OA | 1 | 4.01(2.35, 6.85) | <0.001 | ||
| Hip OA | 3 | 1.14(0.91, 1.44) | 0.249 | ||
| HWE | Yes | 1 | 0.63(0.46, 0.86) | 0.004 | |
| No | 10 | 1.34(1.04, 1.74) | 0.025 | ||
| Genotype methods | PCR-RFLP | 4 | 1.75(0.73, 4.19) | 0.206 | |
| PCR | 1 | 1.12(0.63, 2.01) | 0.698 | ||
| KASPar chemistry | 4 | 1.21(1.07, 1.37) | 0.002 | ||
| Taqman | 1 | 0.66(0.30, 1.42) | 0.286 | ||
| MALDI-TOF MS | 1 | 0.85(0.59, 1.22) | 0.373 | ||
| Study quality | Medium | 8 | 1.40(1.02, 1.92) | 0.038 | |
| High | 3 | 0.88(0.66, 1.17) | 0.366 |
Abbreviations: HB, hospital-based controls; PB, population-based controls; SOC, source of controls; TMJOA, temporomandibular joint osteoarthritis. Medium quality: NOS = 5–6; High quality: NOS = 7.