Skip to main content
Log in

Reproductive factors and incidence of epithelial ovarian cancer: a Norwegian prospective study

  • Research Papers
  • Published:
Cancer Causes & Control Aims and scope Submit manuscript

To examine relations between the risk of epithelial ovarian cancer and time-related effects of pregnancies, we analyzed data from a prospective study of 1,145,076 women in Norway aged 20 to 56 years. The mean follow-up time per woman was 16.4 years and a total of 1,694 women were diagnosed with epithelial ovarian cancer. Incidence rate ratios (IRR) were estimated by Poisson regression analysis of person-years at risk. The risk of epithelial ovarian cancer decreased with an increasing number of full-term pregnancies (IRR=0.56,95 percent confidence interval = 0.48–0.67 for three pregnancies cf one). However, no further reduction in risk was seen after the third pregnancy. The association with parity became weaker with increasing age at last birth. Further, the reduction in risk among parous women compared with nulliparous women was more pronounced shortly after birth. Both higher age at last birth and shorter time since last birth were associated with a reduction in risk, although these relations were seen mainly for the first and second births. Increasing age at first birth was associated with a decrease in risk among uniparous women but not among multiparous women. Our results indicate that the relations between the incidence of epithelial ovarian cancer and reproductive factors are more complex than previously believed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Franceschi S. Reproductive factors and cancers of the breast, ovary and endometrium. Eur J Cancer Clin Oncol 1989; 25: 1933–43.

    Google Scholar 

  2. Albrektsen G, Heuch I, Tretli S, Kvåle G, Breast cancer incidence before age 55 in relation to parity and age at first and last births: a prospective study of one million Norwegian women. Epidemiology 1994; 5: 604–11.

    Google Scholar 

  3. World Health Organization. International Classification of Diseases, Seventh Revision, Geneva, Switzerland: WHO, 1957.

    Google Scholar 

  4. Breslow NE, Day NE. Statistical Methods in Cancer Research. Vol. 2. The Design and Analysis of Cohort Studies. Lyon, France: International Agency for Research on Cancer 1987; IARC Sci. Pub. No. 82: 119–76.

    Google Scholar 

  5. Preston DL, Lubin JH, Pierce DA, McConney ME. EPICURE—Risk Regression and Data Analysis Sofware, Seattle, WA (USA): Hirosoft International Corporation, 1993.

    Google Scholar 

  6. Adami HO, Hsieh C-c, Lambe M, et al. Parity, age at first childbirth, and risk of ovarian cancer. Lancet 1994; 344: 1250–4.

    Google Scholar 

  7. Chen Y, Wu PC, Lang JH, Ge WJ, Hartge P, Brinton LA. Risk factors for epithelial ovarian cancer in Beijing, China. Int J Epidemiol 1992; 21: 23–9.

    Google Scholar 

  8. Franceschi S, LaVecchia C, Helmrich SP Mangioni C, Tognoni G. Risk factors for epithelial ovarian cancer in Italy, Am J Epidemiol 1982; 115: 714–9.

    Google Scholar 

  9. Gwinn ML, Lee NC, Rhodes PH, Layde PM, Rubin GL. Pregnancy, breast feeding, and oral contraceptives and the risk of epithelial ovarian cancer. J Clin Epidemiol 1990; 43: 559–68.

    Google Scholar 

  10. John EM, Whittemore AS, Harris R, Intyre J, Collaborative Ovarian Cancer Group. Characteristics relating to ovarian cancer risk: Collaborative analysis of seven U.S.case-control studies. Epithelial ovarian cancer in black women. JNCI 1993; 85: 142–7.

    Google Scholar 

  11. Kvåle G, Heuch I, Nilssen S, Beral V. Reproductive factors and risk of ovarian cancer: a prospective study. Int J Cancer 1988; 42: 246–51.

    Google Scholar 

  12. Lesher L., McGowan L, Hartge P, Hoover R. Age at first birth and risk of epithelial ovarian cancer (Letter). JNCI 1985; 74: 1361–2.

    Google Scholar 

  13. Lund E. Mortality from ovarian cancer among women with many children, Int J Epidemiol 1992; 21: 872–6.

    Google Scholar 

  14. McGowan L, Norris HJ, Hartge P, Hoover R, Lesher L. Risk factors in ovarian cancer. Eur J Gynaec Oncol 1988; 9: 195–8.

    Google Scholar 

  15. Mori M, Harabuchi I, Miyake H, Casagrande JT, Henderson BE, Ross RK. Reproductive, genetic, and dietary risk factors for ovarian cancer. Am J Epidemiol 1988; 128: 771–7.

    Google Scholar 

  16. Negri E, Franceschi S, Tzonou A, et al. Pooled analysis of 3 European case-control studies: I. Reproductive factors and risk of epithelial ovarian cancer. Int J Cancer 1991 49: 50–6.

    Google Scholar 

  17. Risch HA, Marrett LD, Howe GR. Parity, contraception, infertility, and the risk of epithelial ovarian cancer. Am J Epidemiol 1994; 140: 585–97.

    Google Scholar 

  18. Shu XO, Brinton LA, Gao YT, Yuan JM. Population-based case-control study of ovarian cancer in Shanghai. Cancer Res 1989; 49: 3670–4.

    Google Scholar 

  19. Whittemore AS, Harris R, Itnyre J, the Collaborative Ovarian Cancer Group. Characteristics relating to ovarian cancer risk: Collaborative analysis of 12 US case-control studies, II. Invasive epithelial ovarian cancers in white women. Am J Epidemiol 1992; 136: 1184–203.

    Google Scholar 

  20. LaVecchia C, Decarli A, Franceschi S, Regallo M, Tognoni G. Age at first birth and the risk of epithelial ovarian cancer. JNCI 1984; 23: 665–6.

    Google Scholar 

  21. Polychronopoulou A, Tzonou A, Hsich C-c, et al. Reproductive variables, tobacco, ethanol, coffee and somatometry as risk factors for ovarian cancer. Int J Cancer 1993; 55: 402–7.

    Google Scholar 

  22. Tavani A, Negri E, Franceschi S, Parazzini F, LaVecchia C. Risk factors for epithelial ovarian cancer in women under age 45. Eur J Cancer 1993; 29A: 1297–301.

    Google Scholar 

  23. Whittemore AS. Peronal characteristies relating to risk of invasive epithelial ovarian cancer in older women in the United States. Cancer 1993; 71: 558–65.

    Google Scholar 

  24. Cramer DW, Hutchison GB, Welch WR, Scully RE, Ryan KJ. Determinants of ovarian cancer risk. I. Reproductive experiences and family history. JNCI 1983; 71: 711–6.

    Google Scholar 

  25. Szamborski J, Czerwinski W, Gadomska H, Kowalski M, Wacker-Pujdak B. Case-control study of high risk factors in ovarian carcinomas. Gynecol Oncol 1981; 11: 8–16.

    Google Scholar 

  26. Cramer DW, Devesa SS, Welch WR Trends in the incidence of endometrioid and clear cell cancers of the ovary in the United States. Am J Epidemiol 1981; 114: 201–8.

    Google Scholar 

  27. Weiss NS, Lyon JL, Krishnamurthy S, Dietert SE, Liff JM, Daling JR. Noncontraceptive estrogen use and the occurrence of ovarian cancer. JNCI 1982; 68: 95–8.

    Google Scholar 

  28. Albrektsen G, Heuch I, Tretli S, Kvåle G. Is the risk of cancer of the corpus uteri reduced by a recent pregnancy. A prospective study of 765,756 Norwegian women. Int J Cancer 1995; 61: 485–90.

    Google Scholar 

  29. Franceschi S, Parazzini F, Negri E, et al. Pooled analysis of 3 European case-control studies of ovarian cancer: III. Oral contraceptive use. Int J Cancer 1991; 49: 61–5.

    Google Scholar 

  30. Fathalla MF. Incessant ovlation—a factor in ovarian neoplasia? Lancet 1971: 2: 163.

    Google Scholar 

  31. Cramer DW, Welch WR. Determinants of ovarian cancer risk. II. Inferences regarding pathogenesis. JNCI 1983; 71: 717–21.

    Google Scholar 

  32. Stadel BV. The etiology and prevention of ovarian cancer. Am J Obstet Gynecol 1975; 123: 772–4.

    Google Scholar 

  33. Whittemore AS, Harris R, Itnyre J, the Collaborative Ovarian Cancer Group. Characteristics relating to ovarian cancer risk: Collaborative analysis of 12 US case-control studies. IV. The pathogenesis of epithelial ovarian cancer. Am J Epidemiol 1992; 136: 1212–20.

    Google Scholar 

  34. LaVecchia C, Franceschi S, Gallus G, Decarli A, Liberati A, Tognoni G. Incessant ovulation and ovarian cancer: a critical approach. Int J Epidemiol 1983; 12: 161–4.

    Google Scholar 

  35. Risch HA, Weiss NS, Lyon JL, Daling JR, Liff JM. Events of reproductive life and the incidence of epithelial ovarian cancer. Am J Epidemiol 1983; 117: 128–39.

    Google Scholar 

  36. Scott JS. How to induce ovarian cancer: and how not to. Br Med J 1984; 289: 781.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Additional information

This project is funded by a grant from the Norwegian Cancer Society.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Albrektsen, G., Heuch, I. & Kvåle, G. Reproductive factors and incidence of epithelial ovarian cancer: a Norwegian prospective study. Cancer Causes Control 7, 421–427 (1996). https://doi.org/10.1007/BF00052668

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00052668

Key words

Navigation