Parity and breastfeeding among African-American women: differential effects on breast cancer risk by estrogen receptor status in the Women’s Circle of Health Study
- 721 Downloads
It has long been held that parity reduces risk of breast cancer. However, accumulating evidence indicates that the effects of parity, as well as breastfeeding, may vary according to estrogen receptor (ER) status. We evaluated these associations in a case–control study among African-American women in New York City and New Jersey.
In the Women’s Circle of Health Study, including 786 African-American women with breast cancer and 1,015 controls, data on reproductive histories were collected from in-person interviews, with tumor characteristics abstracted from pathology reports. We calculated number of live births and months breastfeeding for each child, and examined each in relation to breast cancer by ER status, and for triple-negative (TN) breast cancer.
Although associations were not statistically significant, having children was associated with reduced risk of ER+ breast cancer [odds ratio (OR) 0.82, 95 % confidence interval (CI) 0.58–1.16], but increased risk of ER− tumors, with associations most pronounced for TN breast cancer (OR 1.81, 95 % CI 0.93–3.51). Breastfeeding gave no additional benefit for ER+ cancer, but reduced the risk of ER− disease associated with parity.
Accumulating data from a number of studies, as well as our own in African-American women, indicate that the effects of parity and breastfeeding differ by ER status. African-American women are more likely to have children and not to breastfeed, and to have ER− and TN breast cancer. It is possible that breastfeeding in this population could reduce risk of more aggressive breast cancers.
KeywordsBreast cancer Parity Breastfeeding African-American, estrogen receptor negative Triple-negative
This work was supported by Grants from the US Army Medical Research and Material Command (DAMD-17-01-1-0334), the National Cancer Institute (R01 CA100598, P01 CA151135, K22 CA138563, P30CA072720, P30 CA016056), the Breast Cancer Research Foundation, and a gift from the Philip L Hubbell family. The New Jersey State Cancer Registry (NJSCR) is a participant in the Centers for Disease Control and Prevention’s National Program of Cancer Registries and is a National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Expansion Registry. The NJSCR is supported by the Centers for Disease Control and Prevention under cooperative agreement 1US58DP003931-01 awarded to the New Jersey Department of Health. The collection of New Jersey cancer incidence data is also supported by the National Cancer Institute’s SEER Program under contract N01PC-2010-00027 and the State of New Jersey. The funding agents played no role in design, in the collection, analysis, and interpretation of data, in the writing of the manuscript, or in the decision to submit the manuscript for publication.
- 2.DeVita VT Jr, Hellman S, Rosenberg SA (2012) Cancer: principles and practice of oncology. Lippincott Williams & Wilkins, New YorkGoogle Scholar
- 11.Ambrosone CB, Ciupak GL, Bandera EV et al (2009) Conducting molecular epidemiological research in the age of HIPAA: A multi-institutional case–control study of breast cancer in African-American and European-American women. J Oncol 2009:1–15Google Scholar
- 13.Bandera EV, Chandran U, Zirpoli G, McCann SE, Ciupak G, Ambrosone CB (2013) Rethinking sources of representative controls for the conduct of case–control studies in minority populations. BMC Med Res Methodol 13:71Google Scholar
- 20.Hamilton BE, Martin JA, Ventura SJ (2013) Births: preliminary data for 2012, Table 2. Natl Vital Stat Rep 62:3. http://www.cdc.gov/nchs/data/nvsr/nvsr62/nvsr62_03.pdf
- 21.McDowell MM, Wang C-Y, Kennedy-Stephenson J (2008) Breastfeeding in the United States: Findings from the National Health and Nutrition Examination Surveys, 1999–2006. NCHS Data Brief 2008. No 5. http://www.cdc.gov/nchs/data/databriefs/db05.pdf