Table 2.
Age- and race-adjusted odds ratios (OR) and 95% confidence intervals (CI) for case–control analyses of associations between epidemiologic risk factors for invasive serous primary peritoneal cancer versus invasive serous epithelial ovarian cancer
| Serous primary peritoneal cancer (N = 62) | Serous epithelial ovarian cancer (N = 495) | Controls (N = 1086) | Serous primary peritoneal cancer versus controls | Serous epithelial ovarian cancer versus controls | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | (%) | N | (%) | N | (%) | OR | (95% CI) | OR | (95% CI) | |
| Age at diagnosis/age at interview (years) | ||||||||||
| 20–49 | 4 | (6.5) | 98 | (19.8) | 325 | (29.9) | ||||
| 50–59 | 21 | (33.9) | 164 | (33.1) | 339 | (31.2) | ||||
| 60–69 | 24 | (38.7) | 162 | (32.7) | 288 | (26.5) | ||||
| 70+ | 13 | (21.0) | 71 | (14.3) | 134 | (12.3) | ||||
| Missing | . | . | . | |||||||
| Race | ||||||||||
| Black | 4 | (6.5) | 67 | (13.5) | 189 | (17.4) | ||||
| White | 56 | (90.3) | 419 | (84.6) | 868 | (79.9) | ||||
| Other | 2 | (3.2) | 7 | (1.4) | 29 | (2.7) | ||||
| Missing | . | 2 | . | |||||||
| Ever been pregnant | ||||||||||
| No | 9 | (14.5) | 65 | (13.1) | 100 | (9.2) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 53 | (85.5) | 428 | (86.5) | 986 | (90.8) | 0.49 | (0.23, 1.05) | 0.59 | (0.42, 0.83) |
| Missing | . | 2 | . | |||||||
| Number of pregnancies | ||||||||||
| 0 | 9 | (14.5) | 65 | (13.1) | 100 | (9.2) | 1.00 | (Referent) | 1.00 | (Referent) |
| 1–2 | 19 | (30.6) | 193 | (39.0) | 427 | (39.3) | 0.44 | (0.19, 1.02) | 0.63 | (0.44, 0.91) |
| 3–4 | 25 | (40.3) | 183 | (37.0) | 417 | (38.4) | 0.55 | (0.24, 1.23) | 0.59 | (0.41, 0.85) |
| 5+ | 9 | (14.5) | 52 | (10.5) | 142 | (13.1) | 0.48 | (0.18, 1.30) | 0.45 | (0.28, 0.72) |
| Missing | . | 2 | . | |||||||
| P trend | 0.658 | 0.022 | ||||||||
| Age at last pregnancy years* | ||||||||||
| <25 | 6 | (11.3) | 117 | (27.3) | 215 | (21.8) | 1.00 | (Referent) | 1.00 | (Referent) |
| 25–29 | 17 | (32.1) | 155 | (36.2) | 318 | (32.3) | 1.65 | (0.63, 4.29) | 0.84 | (0.62, 1.13) |
| 30–34 | 18 | (34.0) | 100 | (23.4) | 290 | (29.4) | 2.20 | (0.84, 5.72) | 0.62 | (0.45, 0.86) |
| 35+ | 12 | (22.6) | 52 | (12.1) | 160 | (16.2) | 2.78 | (1.00, 7.78) | 0.58 | (0.39, 0.86) |
| Missing | . | 4 | 3 | |||||||
| P trend | 0.126 | 0.001 | ||||||||
| Ever breastfed | ||||||||||
| No | 45 | (72.6) | 344 | (69.5) | 695 | (64.0) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 17 | (27.4) | 151 | (30.5) | 391 | (36.0) | 0.71 | (0.40, 1.27) | 0.80 | (0.64, 1.01) |
| Missing | . | . | . | |||||||
| History of infertility | ||||||||||
| No | 53 | (85.5) | 441 | (89.1) | 985 | (90.7) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 9 | (14.5) | 54 | (10.9) | 101 | (9.3) | 1.88 | (0.89, 3.99) | 1.26 | (0.88, 1.79) |
| Missing | . | . | . | |||||||
| Age at menarche years | ||||||||||
| 0–<12 | 12 | (19.4) | 120 | (24.2) | 216 | (19.9) | 1.00 | (Referent) | 1.00 | (Referent) |
| >=12 | 50 | (80.6) | 370 | (74.7) | 867 | (79.8) | 0.90 | (0.46, 1.73) | 0.72 | (0.55, 0.93) |
| Missing | . | 5 | 3 | |||||||
| Menopausal status | ||||||||||
| Postmenopausal | 55 | (88.7) | 365 | (73.7) | 702 | (64.6) | 1.00 | (Referent) | 1.00 | (Referent) |
| Premenopausal | 7 | (11.3) | 122 | (24.6) | 378 | (34.8) | 0.53 | (0.18, 1.54) | 0.86 | (0.60, 1.24) |
| Missing | . | 8 | 6 | |||||||
| Tubal ligation | ||||||||||
| No | 41 | (66.1) | 353 | (71.3) | 686 | (63.2) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 21 | (33.9) | 140 | (28.3) | 399 | (36.7) | 1.10 | (0.63, 1.93) | 0.72 | (0.57, 0.91) |
| Missing | . | 2 | 1 | |||||||
| Hysterectomy 1 year prior to diagnosis/interview | ||||||||||
| No | 36 | (58.1) | 345 | (69.7) | 834 | (76.8) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 26 | (41.9) | 148 | (29.9) | 251 | (23.1) | 1.98 | (1.16, 3.37) | 1.29 | (1.01, 1.65) |
| Missing | . | 2 | 1 | |||||||
| OC/patch use years | ||||||||||
| Never | 26 | (41.9) | 169 | (34.1) | 308 | (28.4) | 1.00 | (Referent) | 1.00 | (Referent) |
| 0–<1 | 5 | (8.1) | 63 | (12.7) | 108 | (10.0) | 0.63 | (0.24, 1.71) | 1.14 | (0.79, 1.65) |
| 1–<5 | 12 | (19.4) | 114 | (23.0) | 291 | (26.8) | 0.80 | (0.38, 1.70) | 0.82 | (0.61, 1.11) |
| 5+ | 18 | (29.0) | 120 | (24.2) | 343 | (31.3) | 1.13 | (0.56, 2.26) | 0.74 | (0.55, 1.00) |
| Missing | 1 | 29 | 35 | |||||||
| P trend | 0.685 | 0.068 | ||||||||
| Menopausal hormones** | ||||||||||
| No | 18 | (32.7) | 116 | (31.8) | 285 | (40.6) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 37 | (67.3) | 247 | (67.7) | 416 | (59.3) | 1.34 | (0.74, 2.42) | 1.42 | (1.08, 1.86) |
| Missing | . | 2 | 1 | |||||||
| 1st Degree family history of ovarian cancer | ||||||||||
| No | 56 | (90.3) | 463 | (93.5) | 1053 | (97.0) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 6 | (9.7) | 32 | (6.5) | 30 | (2.8) | 3.48 | (1.36, 8.91) | 2.42 | (1.45, 4.05) |
| Missing | . | . | 3 | |||||||
| 1st Degree family history of breast cancer | ||||||||||
| No | 53 | (85.5) | 394 | (79.6) | 933 | (85.9) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 9 | (14.5) | 101 | (20.4) | 150 | (13.8) | 0.84 | (0.40, 1.75) | 1.52 | (1.14, 2.01) |
| Missing | . | . | 3 | |||||||
| Talc use | ||||||||||
| No | 31 | (50.0) | 204 | (41.2) | 412 | (37.9) | 1.00 | (Referent) | 1.00 | (Referent) |
| Yes | 17 | (27.4) | 158 | (31.9) | 275 | (25.3) | 0.76 | (0.41, 1.42) | 1.15 | (0.89, 1.49) |
| Missing | 14 | 133 | 399 | |||||||
| BMI (kg/m 2 ) 1 year before diagnosis or interview | ||||||||||
| 13–<25 | 29 | (46.8) | 193 | (39.0) | 409 | (37.7) | 1.00 | (Referent) | 1.00 | (Referent) |
| 25–<30 | 15 | (24.2) | 140 | (28.3) | 321 | (29.6) | 0.63 | (0.33, 1.21) | 0.92 | (0.70, 1.19) |
| 30–<35 | 8 | (12.9) | 81 | (16.4) | 172 | (15.8) | 0.69 | (0.31, 1.56) | 1.02 | (0.74, 1.40) |
| 35+ | 9 | (14.5) | 64 | (12.9) | 147 | (13.5) | 1.04 | (0.47, 2.30) | 1.01 | (0.71, 1.43) |
| Missing | 1 | 17 | 37 | |||||||
| P trend | 0.837 | 0.624 | ||||||||
Adjustment for age at diagnosis/interview was accomplished in all the analyses using a linear term for age with the exception of age at last pregnancy where both the linear term and quadratic terms were included
* Restricted to those ever pregnant and also controlling for number of pregnancies
** Among postmenopausal