Table 2. Association between reproductive and hormonal exposures and ovarian cancer-specific survival.
| OC deaths/na | HR model 1b | 95% CI | P-value | OC deaths/nc | HR model 2d | 95% CI | P-value | |
|---|---|---|---|---|---|---|---|---|
| Age at diagnosis | 638/1394 | 1.25 | 1.17, 1.35 | <0.0001 | 404/833 | 1.19 | 1.09, 1.31 | 0.0002 |
| Histology | ||||||||
| Serous | 439/758 | 1.00 | Ref. | Ref. | 280/468 | 1.00 | Ref. | Ref. |
| Mucinous | 25/115 | 0.50 | 0.33, 0.76 | 0.001 | 20/67 | 1.26 | 0.90, 1.76 | 0.18 |
| Endometrioid | 80/298 | 0.58 | 0.45, 0.75 | <0.0001 | 45/164 | 1.16 | 0.66, 2.01 | 0.61 |
| Clear cell | 24/94 | 0.62 | 0.41, 0.95 | 0.03 | 17/50 | 0.85 | 0.55, 1.32 | 0.48 |
| Other | 70/129 | 0.87 | 0.67, 1.12 | 0.27 | 42/84 | 1.34 | 0.75, 2.40 | 0.33 |
| Stage | ||||||||
| I | 29/254 | 1.00 | Ref. | Ref. | 18/173 | 1.00 | Ref. | Ref. |
| II | 82/247 | 2.82 | 1.84, 4.33 | <0.0001 | 59/142 | 4.09 | 2.37, 7.04 | <0.0001 |
| III | 402/699 | 6.38 | 4.28, 9.51 | <0.0001 | 288/455 | 8.73 | 5.18, 14.72 | <0.0001 |
| IV | 125/194 | 9.17 | 5.95, 14.13 | <0.0001 | 39/63 | 11.44 | 6.23, 21.02 | <0.0001 |
| Tumour characteristics | ||||||||
| Residual disease | ||||||||
| No | 92/300 | 1.00 | Ref. | Ref. | 92/300 | 1.00 | Ref. | Ref. |
| Yes | 312/533 | 1.64 | 1.28, 2.11 | 0.0001 | 312/533 | 1.64 | 1.28, 2.11 | 0.0001 |
| Reproductive/hormonal factors | ||||||||
| Age at menarche (years), continuous | 585/1297 | 1.02 | 0.96, 1.07 | 0.58 | 369/762 | 1.04 | 0.97, 1.11 | 0.30 |
| Age at menarche (years) | ||||||||
| ⩽12 | 219/489 | 1.00 | Ref. | Ref. | 146/301 | 1.00 | Ref. | Ref. |
| 13 | 179/409 | 0.97 | 0.79, 1.18 | 0.74 | 109/231 | 1.00 | 0.77, 1.29 | 0.98 |
| 14 | 100/221 | 0.91 | 0.72, 1.16 | 0.44 | 60/123 | 1.03 | 0.76, 1.39 | 0.87 |
| >14 | 87/178 | 1.10 | 0.85, 1.41 | 0.47 | 54/107 | 1.13 | 0.83, 1.56 | 0.44 |
| Parity, continuouse | 465/1037 | 1.04 | 0.97, 1.11 | 0.26 | 289/611 | 1.04 | 0.95, 1.13 | 0.41 |
| Paritye | ||||||||
| 1 | 73/190 | 1.00 | Ref. | Ref. | 52/111 | 1.00 | Ref. | Ref. |
| 2 | 178/407 | 1.19 | 0.90, 1.56 | 0.22 | 108/244 | 0.92 | 0.66, 1.28 | 0.61 |
| >3 | 214/440 | 1.13 | 0.86, 1.49 | 0.37 | 129/256 | 0.96 | 0.69, 1.34 | 0.82 |
| Parity, never/ever | ||||||||
| Nulliparous | 99/218 | 1.00 | Ref. | Ref. | 64/126 | 1.00 | Ref. | Ref. |
| Parous | 487/1084 | 0.82 | 0.66, 1.02 | 0.07 | 305/638 | 0.71 | 0.54, 0.93 | 0.01 |
| Age at first birth (years), continuouse | 408/909 | 1.00 | 0.98, 1.02 | 0.94 | 250/520 | 1.01 | 0.98, 1.03 | 0.70 |
| Age at first birthe | ||||||||
| <20 | 54/117 | 1.00 | Ref. | Ref. | 33/68 | 1.00 | Ref. | Ref. |
| 20–30 | 306/685 | 0.90 | 0.67, 1.20 | 0.45 | 187/387 | 0.96 | 0.66, 1.40 | 0.84 |
| >30 | 48/107 | 0.99 | 0.67, 1.46 | 0.94 | 30/65 | 1.02 | 0.62, 1.68 | 0.94 |
| Breastfede | ||||||||
| Never | 197/434 | 1.00 | Ref. | Ref. | 124/256 | 1.00 | Ref. | Ref. |
| Ever | 268/603 | 1.07 | 0.89, 1.28 | 0.49 | 165/355 | 0.96 | 0.76, 1.21 | 0.71 |
| Duration of breastfeeding (months), continuouse | 465/1037 | 1.00 | 1.00, 1.01 | 0.50 | 285/605 | 1.01 | 1.00, 1.01 | 0.27 |
| Duration of breastfeeding (months)e | ||||||||
| 0 | 192/427 | 1.00 | Ref. | Ref. | 121/252 | 1.00 | Ref. | Ref. |
| 1–6 | 122/286 | 1.03 | 0.82, 1.30 | 0.78 | 82/180 | 0.91 | 0.68, 1.20 | 0.50 |
| >6 | 144/313 | 1.11 | 0.90, 1.38 | 0.34 | 82/173 | 1.04 | 0.79, 1.38 | 0.77 |
| Oral contraceptive use | ||||||||
| Never | 284/568 | 1.00 | Ref. | Ref. | 167/328 | 1.00 | Ref. | Ref. |
| Ever | 302/732 | 1.00 | 0.83, 1.20 | 0.99 | 203/437 | 1.16 | 0.92, 1.47 | 0.20 |
| Duration of oral contraceptive use (years), continuous | 482/1096 | 1.00 | 0.98, 1.02 | 0.99 | 308/648 | 1.02 | 0.99, 1.04 | 0.27 |
| Duration of oral contraceptive use (years) | ||||||||
| 0 | 268/570 | 1.00 | Ref. | Ref. | 164/336 | 1.00 | Ref. | Ref. |
| 1–5 | 119/307 | 1.00 | 0.80, 1.25 | 0.98 | 79/185 | 1.06 | 0.81, 1.41 | 0.66 |
| >5 | 96/219 | 1.08 | 0.84, 1.38 | 0.55 | 65/127 | 1.23 | 0.91, 1.67 | 0.18 |
| Oestrogen HRT | ||||||||
| Never | 424/977 | 1.00 | Ref. | Ref. | 280/577 | 1.00 | Ref. | Ref. |
| Ever | 160/322 | 0.90 | 0.75, 1.09 | 0.28 | 89/187 | 0.79 | 0.62, 1.01 | 0.06 |
| Tamoxifen use | ||||||||
| Never | 164/414 | 1.00 | Ref. | Ref. | 82/183 | 1.00 | Ref. | Ref. |
| Ever | 3/7 | 2.54 | 0.77, 8.38 | 0.13 | 3/4 | 3.57 | 0.99, 12.93 | 0.05 |
| Fertility treatment | ||||||||
| Never | 570/1258 | 1.00 | Ref. | Ref. | 359/741 | 1.00 | Ref. | Ref. |
| Ever | 16/38 | 0.89 | 0.54, 1.47 | 0.64 | 11/20 | 1.24 | 0.67, 2.29 | 0.50 |
| Endometriosis | ||||||||
| No | 551/1219 | 1.00 | Ref. | Ref. | 349/716 | 1.00 | Ref. | Ref. |
| Yes | 31/70 | 1.27 | 0.88, 1.83 | 0.21 | 17/38 | 1.10 | 0.67, 1.81 | 0.71 |
| Age at natural menopause (years), continuous | 341/692 | 0.98 | 0.96, 1.01 | 0.11 | 208/403 | 0.98 | 0.94, 1.01 | 0.14 |
| Age at natural menopause | ||||||||
| ⩽47 | 97/175 | 1.00 | Ref. | Ref. | 55/99 | 1.00 | Ref. | Ref. |
| >47–50 | 118/228 | 0.89 | 0.68, 1.17 | 0.41 | 78/138 | 0.94 | 0.66, 1.34 | 0.74 |
| >50–52 | 61/147 | 0.78 | 0.56, 1.07 | 0.12 | 36/87 | 0.74 | 0.48, 1.14 | 0.17 |
| >52 | 65/142 | 0.75 | 0.55, 1.03 | 0.08 | 39/79 | 0.69 | 0.45, 1.05 | 0.08 |
| Menopausal status at diagnosis | ||||||||
| Premenopausal | 131/370 | 1.00 | Ref. | Ref. | 89/211 | 1.00 | Ref. | Ref. |
| Postmenopausal | 449/907 | 1.01 | 0.77, 1.32 | 0.97 | 278/542 | 0.96 | 0.69, 1.35 | 0.83 |
| IUD use | ||||||||
| Never | 487/1090 | 1.00 | Ref. | Ref. | 306/638 | 1.00 | Ref. | Ref. |
| Ever | 98/206 | 1.09 | 0.87, 1.36 | 0.45 | 63/122 | 1.06 | 0.80, 1.40 | 0.71 |
| Tubal ligation | ||||||||
| Never | 438/998 | 1.00 | Ref. | Ref. | 276/581 | 1.00 | Ref. | Ref. |
| Ever | 148/302 | 1.08 | 0.89, 1.31 | 0.43 | 94/183 | 0.98 | 0.77, 1.25 | 0.87 |
| Number of ovulatory cycles | ||||||||
| ⩽322.28 | 95/228 | 1.00 | Ref. | Ref. | 61/130 | 1.00 | Ref. | Ref. |
| >322.28–389.52 | 105/230 | 0.87 | 0.65, 1.16 | 0.35 | 65/134 | 0.82 | 0.58, 1.18 | 0.29 |
| >389.52–439.42 | 101/225 | 0.78 | 0.58, 1.05 | 0.10 | 62/133 | 0.74 | 0.50, 1.08 | 0.12 |
| >439.42 | 102/225 | 0.82 | 0.60, 1.11 | 0.20 | 65/143 | 0.63 | 0.43, 0.94 | 0.02 |
Abbreviations: CI=confidence interval; HR=hazard ratio; HRT = hormone replacement therapy; IUD=intrauterine device; OC=ovarian cancer; ref.=reference value.
There were a total of n=1394 in model 1 because 27 participants had missing information on tumour stage.
Adjusted for age at diagnosis (continuous), histology (serous, mucinous, endometrioid, clear cell, other), and stage (I, II, III, IV).
There were a total of n=833 in model 2 because 588 participants had missing information on residual disease after debulking surgery.
Adjusted for model 1 and residual disease (no residual disease, any residual disease).
Among parous women only.