Introduction
Materials and methods
Study population
Exposure information
Cancer
Other covariates
Statistical analyses
Results
Characteristic | Not infertile (n = 2,765,347) | Infertile (n = 117,500) | ||
---|---|---|---|---|
Birthyear
| N | % | N | % |
1942–1949 | 479,293 | 17.3 | 13,704 | 11.7 |
1950–1959 | 514,247 | 18.6 | 25,747 | 21.9 |
1960–1969 | 541,828 | 19.6 | 25,858 | 22.0 |
1970–1979 | 501,622 | 18.1 | 37,080 | 31.6 |
1980–1992 | 728,357 | 26.3 | 15,111 | 12.9 |
Highest education level
| ||||
9-year compulsory | 391,864 | 14.2 | 11,625 | 9.9 |
Secondary school 1–2 years | 632,388 | 22.9 | 28,726 | 24.4 |
Secondary school 3 years | 627,863 | 22.7 | 23,930 | 20.4 |
Higher education < 3 years | 403,416 | 14.6 | 17,128 | 14.6 |
Higher education ≥ 3 years | 598,666 | 21.6 | 35,415 | 30.1 |
Missing | 111,150 | 4.0 | 676 | 0.6 |
Country of birth
| ||||
Nordic | 2,591,062 | 93.7 | 111,240 | 94.7 |
Non-Nordic | 172,888 | 6.3 | 6260 | 5.3 |
Missing | 1397 | 0.1 | 0 | 0.0 |
Ovulatory disturbances, ever
| 41,617 | 1.5 | 19,299 | 16.4 |
Endometriosis, ever
| 54,797 | 2.0 | 14,030 | 11.9 |
Age at first birth
| ||||
Nulliparous | 902,934 | 32.7 | 36,589 | 31.1 |
< 25 years | 914,220 | 33.1 | 19,852 | 16.9 |
25–34 years | 871,638 | 31.5 | 45,914 | 39.1 |
≥ 35 years | 76,555 | 2.8 | 15,145 | 12.9 |
Parity at end of follow-up | ||||
Nulliparous | 902,934 | 32.7 | 36,589 | 31.1 |
One child | 392,630 | 14.2 | 33,638 | 28.6 |
Two children | 925,135 | 33.5 | 33,028 | 28.1 |
Three children | 405,158 | 14.7 | 11,038 | 9.4 |
Four children | 139,490 | 5.0 | 3207 | 2.7 |
Salpingectomy
| 77,746 | 2.8 | 12,311 | 10.5 |
Hysterectomy
| 103,909 | 3.8 | 6377 | 5.4 |
Bilateral oophorectomy
| 22,638 | 0.8 | 1974 | 1.7 |
Breast cancer
Cancer cases | Person-years | Age-adjusted | Multivariablea | |||
---|---|---|---|---|---|---|
HR (95% CI) | p value | HR (95% CI) | p value | |||
Infertility
| ||||||
No infertility | 51,575 | 64,702,934 | 1.00 (reference) | . | 1.00 (reference) | . |
Infertility | 2112 | 1,759,886 | 1.05 (1.00–1.10) | 0.029 | 0.96 (0.92–1.01) | 0.111 |
Infertility and related diagnoses
| ||||||
No diagnosis | 49,822 | 63,500,014 | 1.00 (reference) | . | 1.00 (reference) | . |
Ovulatory disturbances | 330 | 374,986 | 0.97 (0.87–1.08) | 0.589 | 0.94 (0.84–1.05) | 0.274 |
Endometriosis | 1423 | 827,934 | 1.01 (0.95–1.06) | 0.845 | 1.02 (0.96–1.07) | 0.569 |
Infertility | 1733 | 1,404,738 | 1.06 (1.01–1.11) | 0.024 | 0.98 (0.93–1.02) | 0.309 |
Infertility and ovulatory disturbances | 114 | 153,635 | 0.99 (0.82–1.18) | 0.874 | 0.89 (0.74–1.07) | 0.206 |
Infertility and endometriosis | 265 | 201,513 | 1.03 (0.92–1.17) | 0.592 | 0.93 (0.83–1.06) | 0.275 |
Ovarian cancer
Cancer cases | Person-years | Age-adjusted | Multivariablea | |||
---|---|---|---|---|---|---|
HR (95% CI) | p value | HR (95% CI) | p value | |||
Infertility
| ||||||
No infertility | 6060 | 64,479,845 | 1.00 (reference) | . | 1.00 (reference) | . |
Infertility | 375 | 1,739,692 | 1.73 (1.56–1.92) | < 0.001 | 1.53 (1.38–1.71) | < 0.001 |
Infertility and related diagnoses
| ||||||
No diagnosis | 5793 | 63,340,911 | 1.00 (reference) | . | 1.00 (reference) | . |
Ovulatory disturbances | 58 | 371,256 | 1.53 (1.18–1.98) | 0.001 | 1.53 (1.18–1.98) | 0.001 |
Endometriosis | 209 | 767,678 | 1.55 (1.35–1.78) | < 0.001 | 1.77 (1.53–2.05) | < 0.001 |
Infertility | 299 | 1,393,212 | 1.71 (1.52–1.92) | < 0.001 | 1.53 (1.36–1.72) | < 0.001 |
Infertility and ovulatory disturbances | 15 | 152,397 | 1.15 (0.69–1.91) | 0.589 | 1.12 (0.68–1.87) | 0.651 |
Infertility and endometriosis | 61 | 194,084 | 2.38 (1.85–3.06) | < 0.001 | 2.19 (1.70–2.82) | < 0.001 |
Endometrial cancer
Cancer cases | Person-years | Age-adjusted | Multivariablea | |||
---|---|---|---|---|---|---|
HR (95% CI) | p value | HR (95% CI) | p value | |||
Infertility
| ||||||
No infertility | 5797 | 63,265,993 | 1.00 (reference) | . | 1.00 (reference) | . |
Infertility | 315 | 1,676,408 | 1.55 (1.39–1.74) | < 0.001 | 1.25 (1.11–1.40) | < 0.001 |
Infertility and related diagnoses
| ||||||
No diagnosis | 5651 | 62,380,847 | 1.00 (reference) | . | 1.00 (reference) | . |
Ovulatory disturbances | 57 | 363,077 | 1.52 (1.17–1.97) | 0.002 | 1.45 (1.12–1.88) | 0.005 |
Endometriosis | 89 | 522,069 | 1.00 (0.81–1.24) | 0.985 | 0.94 (0.76–1.17) | 0.584 |
Infertility | 258 | 1,351,728 | 1.51 (1.33–1.71) | < 0.001 | 1.21 (1.07–1.38) | 0.003 |
Infertility and ovulatory disturbances | 33 | 149,925 | 3.33 (2.37–4.70) | < 0.001 | 2.90 (2.05–4.08) | < 0.001 |
Infertility and endometriosis | 24 | 174,755 | 1.14 (0.76–1.70) | 0.534 | 0.87 (0.58–1.30) | 0.503 |