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

Abstract

Purpose It has long been held that parity reduces risk of breast cancer. However, accumulating evidence indicates that the effects of parity, as well as breast feeding, may vary according to estrogen receptor (ER) status. We evaluated these associations in a case-control study among African-American women New York City and New Jersey. Methods In the Women’s Circle of Health Study (WCHS), including 786 African-American women with breast cancer and 1015 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. Results 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. Conclusions 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.

Variants of estrogen-related genes and breast cancer risk in European and African American women

“…Distribution of tumor characteristics, such as the expression of estrogen receptor (ER), varies by age and ethnic/racial background (Ambrosone, et al 2014a; Millikan, et al 2008). Compared to American women of European ancestry (EA), those of African ancestry (AA) are more likely to be diagnosed with breast cancer before age 50, and to have tumors with more aggressive features, such as ER negative status (Amend, et al 2006).…”

The Association of Parity and Breastfeeding with Breast Cancer: A Review

“…Egger`s regression asymmetry test is used for publication bias [13]. To study the effect of a single study on meta-analysis we use the method in [14][15][16][17][18][19][20]. All the statistical analysis were performed with SPSS software on a machine with 4GB of RAM.…”

“…They also suggested that the duration of breastfeeding should be greater than 13 months. On contrary, some researchers found that there is not an association between the reduction of BC and breastfeeding [16,[19][20][21][22][23]]. An inverse result was reported in the studies for the association of parity and BC.…”

“…Eight studies [4,[15][16][17][18][19][20][21] comprising 12,041 breast cancer cases investigated the association between ever-breastfeeding and breast cancer risk. The obtained results from the researches do not lead us to a unique fact.…”

Hormonal contraception increases risk of breast tumor based on clinical breast examination among adult women

“…"no children", "1 child" and "2 children or more"; (20) 4) breastfeeding experience i.e. "breastfeeding for <6 months or never did breastfeeding", and "breastfeeding for 6 months"; (21) 5) HC users (respondents who ever had sexual intercourse) were respondents who had ever used or were currently using contraceptive pills, injections or implants. The responses were divided into 2 categories, i.e.…”