Table 3. Adjusted odds ratio and 95% confidence interval for endometrial cancer in relation to infertility by nulliparity and number of live births in the E2C2 pooled analysis.
|
Infertility |
||||||||
|---|---|---|---|---|---|---|---|---|
|
Never |
Ever |
|||||||
| Case (n=5573) | Control (n=8957) | ORa | Case (n=2304) | Control (n=2509) | ORa | 95% CI | P-interactionb | |
|
Nulliparity | ||||||||
| Parous | 4830 | 8177 | 1.00c | 1662 | 2054 | 1.22 | (1.12–1.34) | — |
| Nulliparous | 615 | 695 | 1.00c | 556 | 401 | 1.26 | (1.03–1.55) | 0.44 |
|
Number of births | ||||||||
| 3+ | 2006 | 3536 | 1.00c | 612 | 886 | 1.08 | (0.93–1.25) | — |
| 2 | 1687 | 2987 | 1.00c | 632 | 766 | 1.19 | (1.03–1.37) | — |
| 1 | 1137 | 1654 | 1.00c | 418 | 402 | 1.44 | (1.18–1.75) | — |
| Nulliparous | 615 | 695 | 1.00c | 556 | 401 | 1.26 | (1.03–1.55) | 0.001 |
Abbreviations: CI=confidence interval; E2C2=Epidemiology of Endometrial Cancer Consortium; OR=odds ratio.
Numbers due are not added to the total due to missingness.
a
Adjusted for age, study site, race, ever oral contraceptive use, ever menopausal hormone therapy use, interview year, body mass index. Missing set as separate category for each covariate.
b
Effect modification was assessed using the likelihood ratio test statistic.
c
Referent category.