Abstract
An interview study of 1,362 breast cancer cases and 1,250 controls identified through a multi-centre screening project allowed an evaluation of reproductive determinants of breast cancer. Risk increased linearly with age at first livebirth; women with a birth after age 30 showed 4-5-fold excess risks compared to those with a birth prior to 18, while the risk for nulliparous women resembled that for women whose first birth was in their late twenties. The protection conferred by an early first pregnancy prevailed for pregnancies that ended in a livebirth or stillbirth, but not for those that terminated in other outcomes. Among parous women, a first trimester abortion prior to a livebirth was not associated with an elevated risk, except in the event of multiple miscarriages (RR = 2.2, 95% Cl 0.9-5.1). Although numbers were limited, women who reported an induced abortion in the absence of ever having a livebirth showed some elevation in risk. Age at first livebirth explained most associations, but some residual reduction in risk was noted for multiparous women and those with several births at an early age. There was evidence that delays in birth after marriage increased risk, but this did not explain the high risk associated with late age at first birth.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bain C., Willett W., Rosner B., Speizer F. E., Belanger C., Hennekens C. H. Early age at first birth and decreased risk of breast cancer. Am J Epidemiol. 1981 Nov;114(5):705–709. doi: 10.1093/oxfordjournals.aje.a113241. [DOI] [PubMed] [Google Scholar]
- Breslow N., Powers W. Are there two logistic regressions for retrospective studies? Biometrics. 1978 Mar;34(1):100–105. [PubMed] [Google Scholar]
- Choi N. W., Howe G. R., Miller A. B., Matthews V., Morgan R. W., Munan L., Burch J. D., Feather J., Jain M., Kelly A. An epidemiologic study of breast cancer. Am J Epidemiol. 1978 Jun;107(6):510–521. doi: 10.1093/oxfordjournals.aje.a112570. [DOI] [PubMed] [Google Scholar]
- Cowan L. D., Gordis L., Tonascia J. A., Jones G. S. Breast cancer incidence in women with a history of progesterone deficiency. Am J Epidemiol. 1981 Aug;114(2):209–217. doi: 10.1093/oxfordjournals.aje.a113184. [DOI] [PubMed] [Google Scholar]
- Henderson B. E., Powell D., Rosario I., Keys C., Hanisch R., Young M., Casagrande J., Gerkins V., Pike M. C. An epidemiologic study of breast cancer. J Natl Cancer Inst. 1974 Sep;53(3):609–614. doi: 10.1093/jnci/53.3.609. [DOI] [PubMed] [Google Scholar]
- Lilienfeld A. M., Coombs J., Bross I. D., Chamberlain A. Marital and reproductive experience in a community-wide epidemiological study of breast cancer. Johns Hopkins Med J. 1975 Apr;136(4):157–162. [PubMed] [Google Scholar]
- MacMahon B., Cole P., Lin T. M., Lowe C. R., Mirra A. P., Ravnihar B., Salber E. J., Valaoras V. G., Yuasa S. Age at first birth and breast cancer risk. Bull World Health Organ. 1970;43(2):209–221. [PMC free article] [PubMed] [Google Scholar]
- MacMahon B., Cole P. The ovarian etiology of human breast cancer. Recent Results Cancer Res. 1972;39:185–192. [PubMed] [Google Scholar]
- MacMahon B., Lin T. M., Lowe C. R., Mirra A. P., Ravnihar B., Salber E. J., Trichopoulos D., Valaoras V. G., Yuasa S. Lactation and cancer of the breast. A summary of an international study. Bull World Health Organ. 1970;42(2):185–194. [PMC free article] [PubMed] [Google Scholar]
- Mirra A. P., Cole P., MacMahon B. Breast cancer in an area of high parity: São Paulo, Brazil. Cancer Res. 1971 Feb;31(2):77–83. [PubMed] [Google Scholar]
- Pike M. C., Henderson B. E., Casagrande J. T., Rosario I., Gray G. E. Oral contraceptive use and early abortion as risk factors for breast cancer in young women. Br J Cancer. 1981 Jan;43(1):72–76. doi: 10.1038/bjc.1981.10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thein-Hlaing, Thein-Maung-Myint Risk factors of breast cancer in Burma. Int J Cancer. 1978 Apr 15;21(4):432–437. doi: 10.1002/ijc.2910210406. [DOI] [PubMed] [Google Scholar]
- Tulinius H., Day N. E., Jóhannesson G., Bjarnason O., Gonzales M. Reproductive factors and risk for breast cancer in Iceland. Int J Cancer. 1978 Jun 15;21(6):724–730. doi: 10.1002/ijc.2910210609. [DOI] [PubMed] [Google Scholar]
- Vessey M. P., McPherson K., Yeates D., Doll R. Oral contraceptive use and abortion before first term pregnancy in relation to breast cancer risk. Br J Cancer. 1982 Mar;45(3):327–331. doi: 10.1038/bjc.1982.58. [DOI] [PMC free article] [PubMed] [Google Scholar]