Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2008 Jul;17(7):1723-30.
doi: 10.1158/1055-9965.EPI-07-2824.

Breast cancer risk and hormone receptor status in older women by parity, age of first birth, and breastfeeding: a case-control study

Sarah J Lord  1 , Leslie Bernstein, Karen A Johnson, Kathleen E Malone, Jill A McDonald, Polly A Marchbanks, Michael S Simon, Brian L Strom, Michael F Press, Suzanne G Folger, Ronald T Burkman, Dennis Deapen, Robert Spirtas, Giske Ursin
Affiliations
Comparative Study

Breast cancer risk and hormone receptor status in older women by parity, age of first birth, and breastfeeding: a case-control study

Sarah J Lord et al. Cancer Epidemiol Biomarkers Prev. 2008 Jul.

Abstract

Background: Early age at first birth and multiparity reduce the risk of estrogen receptor-progesterone receptor (ERPR)-positive breast cancer, whereas breastfeeding reduces the risk of both ERPR-positive and ERPR-negative cancers.

Methods: We used multivariable logistic regression analysis to investigate whether age at first birth (<25 or > or =25 years) and breastfeeding (ever/never) modify the long-term effect of parity on risk of ERPR-positive and ERPR-negative cancer using 1,457 incident breast cancer cases and 1,455 controls ages > or =55 years who participated in the Women's Contraceptive and Reproductive Experiences Study.

Results: Women who gave birth before age 25 years had a 36% reduced risk of breast cancer compared with nulligravida that was not observed for women who started their families at an older age (P(heterogeneity) = 0.0007). This protective effect was restricted to ERPR-positive breast cancer (P(heterogeneity) = 0.004). Late age at first birth increased the risk of ERPR-negative cancers. Additional births reduced the risk of ERPR-positive cancers among women with an early first birth (P(trend) = 0.0001) and among women who breastfed (P(trend) = 0.004) but not among older mothers or those who never breastfed. In women with a late first birth who never breastfed, multiparity was associated with increased risk of breast cancer.

Conclusions: These findings suggest that the effect of parity on a woman's long-term risk of breast cancer is modified by age at first full-term pregnancy and possibly by breastfeeding.

PubMed Disclaimer

References

    1. Althuis MD, Fergenbaum JH, Garcia-Closas M, Brinton LA, Madigan MP, Sherman ME. Etiology of hormone receptor-defined breast cancer: a systematic review of the literature. Cancer Epidemiol Biomarkers Prev. 2004;13(10):1558–68. - PubMed
    1. Ma H, Bernstein L, Pike MC, Ursin G. Reproductive factors and breast cancer risk according to joint estrogen and progesterone receptor status: a meta-analysis of epidemiological studies. Breast Cancer Res. 2006;8(4):R43. - PMC - PubMed
    1. Ursin G, Bernstein L, Lord SJ, et al. Reproductive factors and subtypes of breast cancer defined by hormone receptor and histology. Brit J Cancer. 2005;93(3):364–71. - PMC - PubMed
    1. Chandra A, Martinez GM, Mosher WD, Abma JC, Jones J. Fertility, family planning, and reproductive health of U.S. women: Data from the 2002 National Survey of Family Growth. National Center for Health Statistics; Hyattsville, Maryland: 2005. - PubMed
    1. Lambe M, Hsieh C, Trichopoulos D, Ekbom A, Pavia M, Adami HO. Transient increase in the risk of breast cancer after giving birth. New Engl J Med. 1994;331(1):5–9. - PubMed

Publication types

MeSH terms