Table 2 Summary relative risks and 95%CI for the association between endometriosis and endometrial cancer by study characteristics
Subgroup | No.of studies | Pooled RR(95%CI) | Heterogeneity | ||
|---|---|---|---|---|---|
| Â | Random effect | Fixed effect | P | I2(%) | |
The way of information collection | |||||
 questionnaire | 3 | 1.403 (0.762,2.584) | 1.402 (1.036,1.895) | 0.034 | 70.3 |
 database | 10 | 1.743 (1.119,2.716) | 1.921 (1.721,2.143) | 0.000 | 91.6 |
Study design | |||||
 Case-control studies | 3 | 1.358 (0.622,2.963)) | 1.526 (1.096,2.124) | 0.036 | 70.0 |
 Cohort studies | 10 | 1.755 (1.139,2.705) | 1.890 (1.696,2.107) | 0.000 | 91.8 |
Endometriosis assessment | |||||
 Self-report | 3 | 1.403 (0.762,2.584) | 1.470 (1.000,2.170) | 0.034 | 70.3 |
 surgery | 1 | 1.140 (0.570,2.280) | 1.140 (0.570,2.280) | – | – |
 ICD | 5 | 2.389 (1.184,4.820) | 1.953 (1.692,2.254) | 0.000 | 94.500 |
 Other | 4 | 0.964 (0.347,2.677) | 1.937 (1.626,2.308) | 0.000 | 85.800 |
Ascertainment of EC | |||||
 Histopathology reports | 2 | 1.810 (1.048,3.127) | 1.675 (1.191,2.356) | 0.163 | 48.5 |
 ICD | 9 | 1.922 (1.227,3.012) | 1.942 (1.740,2.168) | 0.000 | 92.1 |
 Other | 2 | 0.646 (0.361,1.157) | 0.646 (0.361,1.157) | 0.344 | 0.0 |
NOS score | |||||
 < 7 | 8 | 1.336 (0.918,1.944) | 1.486 (1.316,1.678) | 0.000 | 84.0 |
 ≥ 7 | 5 | 2.457 (1.298,4.652) | 3.252 (2.678,3.951) | 0.000 | 86.4 |
Adjustment for age | |||||
 Yes | 11 | 1.718 (1.071,2.756) | 1.782 (1.570,2.023) | 0.000 | 90.8 |
 No | 2 | 1.339 (0.484,3.701) | 1.994 (1.671,2.380) | 0.005 | 87.4 |
Adjustment for BMI | |||||
 Yes | 3 | 1.403 (0.762,2.584) | 1.402 (1.036,1.895) | 0.034 | 70.3 |
 No | 10 | 1.743(1.119,2.716) | 1.921 (1.721,2.143) | 0.000 | 91.6 |
Adjustment for oral contraceptive use history | |||||
 Yes | 4 | 1.645 (0.903,2.998) | 1.490 (1.112,1.998) | 0.023 | 68.4 |
 No | 9 | 1.644 (1.037,2.604) | 1.909 (1.710,2.131) | 0.000 | 92.5 |
Adjustment for pregnancies | |||||
 Yes | 5 | 1.116 (0.727,1.713) | 1.056 (0.888,1.257) | 0.008 | 70.8 |
 No | 8 | 2.164 (1.470,3.185) | 2.506 (2.205,2.847) | 0.000 | 83.7 |
Adjustment for smoking | |||||
 Yes | 1 | 1.470 (0.998,2.165) | 1.470 (0.998,2.165) | – | – |
 No | 12 | 1.677 (1.120,2.512) | 1.884 (1.693,2.097) | 0.000 | 90.6 |