Variables | No. of studies | x2 for heterogeneity | Model selected | OR a (95% CI b) | P for heterogeneity | Egger’s test (P-value) |
---|---|---|---|---|---|---|
Total | 48 | 1249.27 | Random | 0.90 (0.86, 0.95) | < .001 | – |
Indicators related to higher levels of endogenous sex steroid hormone exposure | 26 | 679.81 | Random | 0.92 (0.87, 0.98) | < .001 | – |
 Younger age at menarche | 18 | 26.51 | Fixed | 0.93 (0.88, 0.98) | .070 | .5729 |
 Older age at menopause | 15 | 81.94 | Random | 0.79 (0.68, 0.93) | < .001 | .3113 |
 Longer reproductive windows | 6 | 13.34 | Random | 0.90 (0.74, 1.10) | .020 | .0566 |
 Longer menstrual cycle | 9 | 20.89 | Random | 0.75 (0.60, 0.94) | .007 | .7938 |
 History of pregnancy | 15 | 37.47 | Random | 0.96 (0.84, 1.10) | < .001 | .3856 |
 Younger age at first pregnancy | 15 | 69.48 | Random | 1.21 (1.05, 1.39) | < .001 | .4527 |
 Multiple pregnancies | 20 | 92.20 | Random | 1.06 (0.94, 1.19) | < .001 | .6782 |
Indicators related to higher levels of exogenous sex steroid hormone exposure | 36 | 419.73 | Random | 0.86 (0.80, 0.93) | < .001 | – |
 History of use of OC c | 22 | 72.67 | Random | 0.88 (0.81, 0.96) | < .001 | .1380 |
 History of use of HRT d | 25 | 327.30 | Random | 0.89 (0.78, 1.01) | < .001 | .1725 |
 Higher isoflavone intake from food | 6 | 14.37 | Random | 0.73 (0.59, 0.89) | .010 | .9897 |