Table 3.
Subgroup analysis of association between PCa risk.
| Category of variables | Studies, n | Heterogeneity | RR (95%CI) | P value for difference | |
|---|---|---|---|---|---|
| I2, % | P value | ||||
| PCa | 7 | 93.0 | < 0.001 | 0.75(0.54–1.03) | 0.075 |
| Type of RR | |||||
| HR | 2 | 70.6 | 0.065 | 1.18(0.71–1.98) | 0.529 |
| OR | 1 | – | – | 0.73(0.66–0.81) | < 0.001 |
| SIR | 4 | 66.1 | 0.031 | 0.58(0.45–0.76) | < 0.001 |
| Study design | |||||
| Cohort study | 5 | 95.1 | < 0.001 | 0.74(0.44–1.22) | 0.231 |
| Case–control study | 2 | 0 | 0.627 | 0.73(0.66–0.82) | < 0.001 |
| Geographic area | |||||
| North America | 2 | 98.2 | < 0.001 | 0.93(0.39–2.21) | 0.873 |
| Asia | 1 | – | – | 0.84(0.48–1.47) | 0.539 |
| Europe | 3 | 0 | 0.930 | 0.73(0.66–0.81) | < 0.001 |
| Australia | 1 | – | – | 0.40(0.28–0.57) | < 0.001 |
| Publication year | |||||
| After 2012 | 5 | 94.3 | < 0.001 | 0.83(0.59–1.16) | 0.274 |
| Before 2012 | 2 | 9.1 | 0.294 | 0.43(0.26–0.71) | 0.001 |
| NOS score | |||||
| ≥ 7 | 5 | 95.3 | < 0.001 | 0.73(0.48–1.13) | 0.160 |
| ≤ 6 | 2 | 0 | 0.644 | 0.74(0.61–0.91) | 0.003 |
HCV = hepatitis C; RCC = renal cell carcinoma; BC = bladder cancer; PCa = prostate cancer; RR = relative risk; HR = hazard ratio; OR = odds ratio; SIR = standardized incidence ratio; NOS = Newcastle–Ottawa Scale;