Table 1.
Results of the metanalyses stratified by region, outcome, study design, year of publication, gender, and quality score.
| Characteristic | N risk estimates | RR, 95% CI | p heterogeneity |
|---|---|---|---|
| Kidney cancer | |||
| Region | |||
| North America | 7 | 1.25(1.04-1.50) | 0.49 |
| Europe | 3 | 1.08(0.90-1.31) | |
| Others | 1 | 1.27(0.96-1.68) | |
| Study design | |||
| Cohort | 8 | 1.12(0.99-1.26) | 0.04 |
| Nested case control | 2 | 1.52(1.22-1.89) | |
| Case control | 1 | 1.10( 0.88-1.37) | |
| Quality score | |||
| Low quality (<8) | 7 | 1.14(1.00-1.30) | 0.60 |
| High quality (>=8) | 4 | 1.24(0.93-1.65) | |
| Outcome | |||
| Incidence | 9 | 1.16(1.04-1.29) | 0.98 |
| Mortality | 3 | 1.15(0.60-2.20) | |
| Year of publication | |||
| <2014 | 4 | 1.12(1.01-1.24) | 0.54 |
| >=2014 | 7 | 1.19(1.00-1.42) | |
| Exposure | |||
| Occupational | 3 | 1.15(0.60-2.20) | 0.96 |
| Environmental | 8 | 1.17(1.05-1.31) | |
| PFAS type | |||
| PFOA | 6 | 1.23(0.99-1.51) | 0.41 |
| PFOS | 1 | 1.39(1.04-1.86) | |
| PFAS | 4 | 1.12(0.95-1.31) | |
| Dose category | |||
| Low | 7 | 0.98(0.83-1.17) | 0.03* |
| Medium | 8 | 1.38 (1.09-1.74) | |
| High | 7 | 1.74 (1.23-2.47) | |
| Liver cancer | |||
| Region | |||
| North America | 8 | 1.08(0.83-1.42) | 0.63 |
| Europe | 5 | 0.97(0.83-1.13) | |
| Others | 3 | 1.20(0.72-2.01) | |
| Study design | |||
| Cohort | 10 | 0.94(0.83-1.08) | 0.25 |
| Nested case control | 3 | 1.37(0.65-2.87) | |
| Case control | 3 | 1.31(0.85-2.00) | |
| Quality score | |||
| Low quality (<8) | 10 | 1.02(0.90-1.14) | 0.55 |
| High quality (>=8) | 6 | 1.16(0.77-1.74) | |
| Outcome | |||
| Incidence | 13 | 1.03(0.90-1.18) | 0.23 |
| Mortality | 5 | 1.31(0.90-1.90) | |
| Year of publication | |||
| <2014 | 6 | 0.96(0.80-1.16) | 0.43 |
| >=2014 | 10 | 1.06(0.91-1.24) | |
| Exposure | |||
| Occupational | 5 | 1.31(0.90-1.90) | 0.18 |
| Environmental | 11 | 1.00(0.88-1.13) | |
| PFAS type | |||
| PFOA | 8 | 1.05(0.93-1.18) | 0.07 |
| PFOS | 4 | 1.86(0.81- 4.25) | |
| PFAS | 4 | 0.91(0.82-1.02) | |
| Dose category | |||
| Low | 8 | 1.12 (0.85-1.48) | 0.37* |
| Medium | 4 | 1.22 (0.66-2.25) | |
| High | 9 | 1.01 (0.68-1.50) | |
| Testicular cancer | |||
| Region | |||
| North America | 5 | 1.28(0.99-1.64) | 0.33 |
| Europe | 2 | 1.19(0.65-2.17) | |
| Others | 1 | 0.76(0.40-1.44) | |
| Study design | |||
| Cohort | 7 | 1.14(0.94-1.37) | 0.67 |
| Nested case control | 0 | - | |
| Case control | 1 | 1.00(0.58-1.73) | |
| Quality score | |||
| Low quality (<8) | 6 | 1.00(0.79-1.26) | 0.11 |
| High quality (>=8) | 2 | 1.35(1.01-1.80) | |
| Outcome | |||
| Incidence | 5 | 1.10(0.88-1.39) | 0.44 |
| Mortality | 3 | 1.80(0.53-6.14) | |
| Year of publication | |||
| <2014 | 5 | 1.28(0.99-1.64) | 0.30 |
| >=2014 | 3 | 1.01(0.69-1.46) | |
| Exposure | |||
| Occupational | 3 | 1.80(0.53-6.14) | 0.44 |
| Environmental | 5 | 1.10(0.88-1.39) | |
| PFAS type | |||
| PFOA | 5 | 1.28(0.99-1.64) | 0.30 |
| PFOS | 0 | - | |
| PFAS | 3 | 1.01(0.70-1.46) | |
| Dose category | |||
| Low | 2 | 0.86(0.59-1.24) | 0.02* |
| Medium | 2 | 1.01(0.33-3.12) | |
| High | 3 | 2.22(1.12-4.39) | |
*denotes the p-value of test for linear trend.