Associations* between nulliparity, number of live births and hysterectomy and risk of any epithelial ovarian cancer, type 1 epithelial ovarian cancer and type 2 epithelial ovarian cancer, by family history of epithelial ovarian cancer in FDRs, SDRs and TDRs
| Case FDRs HR (95% CI) | Control FDRs HR (95% CI) | P value for heterogeneity | Case SDRs HR (95% CI) | Control SDRs HR (95% CI) | P value for heterogeneity | Case TDRs HR (95% CI) | Control TDRs HR (95% CI) | P value for heterogeneity | |
| Nulliparity | |||||||||
| Overall | 1.61 (0.93 to 2.78) | 1.41 (1.11 to 1.80) | 0.500 | 1.27 (0.78 to 2.05) | 1.81 (1.55 to 2.11) | 0.098 | 1.95 (1.08 to 3.55) | 2.44 (2.01 to 2.96) | 0.530 |
| Type 1 | 0.32 (0.05 to 2.23) | 1.19 (0.70 to 2.01) | 0.287 | 3.05 (1.51 to 6.15) | 1.72 (1.30 to 2.28) | 0.259 | 1.64 (0.67 to 4.01) | 3.18 (2.49 to 4.04) | 0.140 |
| Type 2 | 1.93 (1.09 to 3.41) | 1.43 (1.09 to 1.86) | 0.300 | 1.05 (0.62 to 1.78) | 1.81 (1.54 to 2.14) | 0.028 | 2.04 (1.12 to 3.71) | 2.33 (1.89 to 2.86) | 0.751 |
| Number of live births† | |||||||||
| Overall | 0.89 (0.75 to 1.06) | 0.90 (0.84 to 0.96) | 0.451 | 0.95 (0.84 to 1.08) | 0.92 (0.88 to 0.97) | 0.901 | 0.85 (0.77 to 0.94) | 0.85 (0.82 to 0.88) | 0.363 |
| Type 1 | 0.66 (0.39 to 1.10) | 0.90 (0.80 to 1.00) | 0.178 | 1.07 (0.86 to 1.34) | 0.96 (0.89 to 1.04) | 0.841 | 0.87 (0.76 to 1.00) | 0.81 (0.77 to 0.86) | 0.853 |
| Type 2 | 0.95 (0.80 to 1.13) | 0.90 (0.84 to 0.97) | 0.224 | 0.95 (0.83 to 1.09) | 0.93 (0.88 to 0.98) | 0.813 | 0.86 (0.77 to 0.95) | 0.86 (0.83 to 0.89) | 0.343 |
| Hysterectomy | |||||||||
| Overall | ‡ | 0.49 (0.13 to 1.78) | ‡ | 0.47 (0.07 to 3.21) | 0.87 (0.52 to 1.46) | 0.693 | 0.54 (0.11 to 2.78) | 0.89 (0.59 to 1.36) | 0.254 |
| Type 1 | ‡ | 0.05 (0.00 to 2.82) | ‡ | ‡ | 0.96 (0.89 to 1.04) | ‡ | 1.22 (0.29 to 5.07) | 1.62 (0.95 to 2.75) | 0.302 |
| Type 2 | ‡ | 0.47 (0.10 to 2.18) | ‡ | 0.54 (0.08 to 3.68) | 0.76 (0.42 to 1.38) | 0.988 | 0.62 (0.12 to 3.17) | 0.82 (0.52 to 1.30) | 0.409 |
*HR estimated using competing risks Cox proportional hazards models with censoring at death, bilateral oophorectomy or loss to follow-up, and adjustment for birth year, born in Utah, race, ethnicity, ever parous (hysterectomy analysis only), number of live births (hysterectomy analysis only), births outside of Utah, ever unilateral oophorectomy, ever unilateral salpingectomy, ever bilateral salpingectomy, ever tubal ligation, ever pelvic surgery not otherwise specified and ever hysterectomy (parity analyses only).
†Number of live births evaluated among parous women only.
‡Models do not converge.
FDR, first-degree relative; SDR, second-degree relative; TDR, third-degree relative.