Table 2 Summary risk estimates of the association between parity and bladder cancer
From: Parity and bladder cancer risk: a dose-response meta-analysis
No. of reports | RR (95% CI) | I2 (%) | P value | |
|---|---|---|---|---|
Overall | 13 | 0.76 (0.70–0.82) | 0 | 0.795 |
Number of parity | ||||
1 ~ 2 vs. 0 | 7 | 0.82 (0.71–0.94) | 17.7 | 0.295 |
3 ~ 4 vs. 0 | 7 | 0.79 (0.68–0.91) | 0 | 0.997 |
≥ 5 vs. 0 | 6 | 0.76 (0.66–0.88) | 0 | 0.994 |
Subgroup analysis | ||||
Study design | ||||
Cohort study | 6 | 0.77 (0.71–0.84) | 0 | 0.802 |
Case-control study | 7 | 0.71 (0.60–0.83) | 0 | 0.598 |
Number of cases | ||||
< 250 | 7 | 0.68 (0.56–0.81) | 0 | 0.673 |
> 250 | 6 | 0.78 (0.71–0.84) | 0 | 0.841 |
Location | ||||
USA | 9 | 0.72 (0.65–0.81) | 0 | 0.989 |
Others | 4 | 0.79 (0.71–0.87) | 39.7 | 0.174 |
Smoking | ||||
Never smoking | 5 | 0.47 (0.35–0.63) | 0 | 0.562 |
Ever smoking | 4 | 0.90 (0.67–1.21) | 0 | 0.531 |
Adjustment for smoking | ||||
Yes | 8 | 0.67 (0.57–0.79) | 0 | 0.815 |
No | 5 | 0.79 (0.72–0.86) | 0 | 0.882 |
Adjustment for age | ||||
Yes | 9 | 0.77 (0.71–0.84) | 0 | 0.850 |
No | 4 | 0.65 (0.52–0.81) | 0 | 0.684 |
Adjustment for BMI | ||||
Yes | 5 | 0.66 (0.53–0.81) | 0 | 0.469 |
No | 8 | 0.76 (0.70–0.82) | 0 | 0.952 |