| Studies | Overall OR (95 % CI) | I2; p | P value | Cases | Controls | p (Egger’s test) |
---|---|---|---|---|---|---|---|
Total | 8 | 21.71 (9.83–47.94) | 0.0 %; 0.495 | <0.001 | 920 | 265 | 0.008 |
 Material: | |||||||
  Urine | 3 | 7.71 (2.65–22.39) | 0.0 %; 0.831 | <0.001 | 320 | 110 |  |
  Tissue | 4 | 53.94 (12.83–226.87) | 0.0 %; 0.986 | <0.001 | 473 | 114 |  |
 Race: | |||||||
  Caucasians | 2 | 8.86 (2.91–27.03) | 24.0 %; 0.251 | <0.001 | 187 | 60 |  |
  Asians | 6 | 35.18 (11.20–110.55) | 0.0 %; 0.903 | <0.001 | 733 | 205 |  |