Table 4. Subgroup analysis of the association between GSTM1-GSTT1 null genotype and HCC risk.
| Polymorphism | Null vs. Present | No. of studies (cases/controls) | Odds ratio | M | Heterogeneity | PE | ||||
| OR [95% CI] | POR | I2 (%) | PH | |||||||
| GSTM1-GSTT1 | All studies | 12(1763/2537) | 1.78[1.26,2.52] | <0.001 | R | 77.7% | <0.001 | 0.535 | ||
| subgroup analyses by geographical location | ||||||||||
| Southeast regions in mainland China | 9(989/1659) | 1.98[1.32,2.95] | <0.001 | R | 70.3% | <0.001 | 0.497 | |||
| Central regions in mainland China | 1(95/103) | 2.72[1.45,5.11] | 0.002 | F | @ | @ | @ | |||
| Taiwan province | 2(679/775) | 1.04[0.81,1.32] | 0.770 | F | 0.0% | 0.536 | @ | |||
| subgroup analyses by number of case | ||||||||||
| <100 | 4(298/393) | 1.73[0.70,4.28] | 0.235 | R | 75.9% | 0.001 | 0.115 | |||
| ≥100 | 8(1465/2144) | 1.70[1.17,2.48] | 0.006 | R | 78.8% | 0.001 | 0.263 | |||
| subgroup analyses by source of control | ||||||||||
| population-based | 9(1411/1503) | 1.75[1.09,2.80] | 0.020 | R | 81.0% | 0.001 | 0.531 | |||
| hospital-based | 3(352/1034) | 1.86[1.16,2.97] | 0.010 | R | 63.8% | 0.063 | 0.856 | |||
M: model of meta-analysis; R: random-effects model; F: fixed-effects model. PH: P value of heterogeneity test. PE: P value of Egger’s test. POR: P<0.001 replace the P = 0.000 and the P less than 0.001. @: P values could not be calculated.