Table 4 Subgroup analysis for studies included in the analysis
Prostate cancer risk | No. of studies | Pooled RR (95% CI) | I2 statistics (%) | P-value for the heterogeneity Q test |
|---|---|---|---|---|
First degree relatives with BCa | 13 | 1.18(1.12,1.25) | 28.70% | 0.156 |
 Cohort | 5 | 1.19(1.12,1.26) | 53.70% | 0.071 |
 Case-control | 7 | 1.26(1.04,1.53) | 6.90% | 0.375 |
 Cross section | 1 | 1.04(0.84,1.29) | – | – |
 European | 4 | 1.12(1.08,1.16) | 0.00% | 0.624 |
 American | 7 | 1.21(1.15,1.27) | 0.00% | 0.618 |
 Asian | 2 | 2.58(1.21,5.54) | 0.00% | 0.472 |
Adjustment for other factors | ||||
 Yes | 10 | 1.17(1.10,1.24) | 25.30% | 0.210 |
 No | 3 | 1.23(1.13,1.34) | 0.00% | 0.383 |
 BCa diagnosis at age ≥ 50 | 2 | 1.06(0.83,1.37) | 45.00% | 0.179 |
 BCa diagnosis at age <50 | 2 | 1.40(0.99,1.98) | 40.00% | 0.195 |
Mother with BCa | 11 | 1.19(1.10,1.28) | 0.00% | 0.686 |
 Cohort | 5 | 1.21(1.11,1.31) | 0.00% | 0.671 |
 Case-control | 5 | 1.14(0.85,1.54) | 7.30% | 0.365 |
 Cross section | 1 | 1.07(0.80,1.43) | – | – |
 European | 2 | 1.09(0.77,1.54) | 0.00% | 0.549 |
 American | 8 | 1.19(1.10,1.29) | 0.00% | 0.480 |
 Asian | 1 | 2.01(0.28,14.40) | – | – |
Adjustment for other factors | ||||
 Yes | 8 | 1.19(1.10,1.28) | 0.10% | 0.428 |
 No | 3 | 1.32(0.75,2.32) | 0.00% | 0.873 |
 Sister with BCa | 10 | 1.25(1.09,1.44) | 43.00% | 0.071 |
 Cohort | 4 | 1.15(1.04,1.28) | 8.40% | 0.351 |
 Case-control | 5 | 1.75(1.14,2.70) | 50.00% | 0.091 |
 Cross section | 1 | 1.30(0.95,1.78) | – | – |
 European | 2 | 1.21(0.93,1.58) | 0.00% | 0.567 |
 American | 7 | 1.26(1.07,1.50) | 55.60% | 0.035 |
 Asian | 1 | 4.03(0.73,22.19) | – | – |
Adjustment for other factors | ||||
 Yes | 8 | 1.24(1.06,1.44) | 48.80% | 0.057 |
 No | 2 | 1.66(0.66,4.18) | 39.20% | 0.200 |
 Daughter with BCa | 4 | 1.74(0.74,4.12) | 43.70% | 0.149 |
 Cohort | 1 | 1.45(1.04,2.03) | 8.40% | 0.351 |
 Case-control | 3 | 2.27(0.44,11.75) | 62.50% | 0.046 |
 European | 2 | 3.74(0.39,35.97) | 79.50% | 0.027 |
 American | 1 | 1.01(0.19,5.28) | – | – |
 Asian | 1 | 1.01(0.18,5.54) | – | – |
Adjustment for other factors | ||||
 Yes | 2 | 3.66(0.26,52.14) | 75.30% | 0.044 |
 No | 2 | 1.43(1.03,1.99) | 0.00% | 0.685 |