Pre- and perinatal factors and incidence of breast cancer in the Black Women’s Health Study

• Published in: Cancer causes & control Vol. 30; no. 1; pp. 87 - 95
• Main Authors: Barber, Lauren E., Bertrand, Kimberly A., Rosenberg, Lynn, Battaglia, Tracy A., Palmer, Julie R.
• Format: Journal Article
• Language: English
• Published: Cham Springer Science + Business Media 01.01.2019; Springer International Publishing; Springer Nature B.V
• Subjects: Adult; African Americans; African Americans - statistics & numerical data; Biomedical and Life Sciences; Biomedicine; Birth Order; Birth Weight; Breast cancer; Breast Feeding; Breast Neoplasms - epidemiology; Breastfeeding & lactation; Cancer; Cancer Research; Childbirth & labor; Cohort Studies; Confidence intervals; Epidemiology; Estrogen receptors; Estrogens; Female; Hazards; Health risk assessment; Health risks; Hematology; Hormone replacement therapy; Humans; Incidence; Low birth weight; Middle Aged; Minority & ethnic groups; Oncology; ORIGINAL PAPER; Parturition; Pregnancy; Premature birth; Proportional Hazards Models; Prospective Studies; Public Health; Risk Factors; Statistical analysis; Weight; Women's Health; Womens health; Prenatal factors; Breast cancer; Perinatal factors; African American women
• ISSN: 0957-5243; 1573-7225
• DOI: 10.1007/s10552-018-1103-3

Purpose The purpose of the study was to investigate the association between pre- or perinatal factors and breast cancer risk among African American women. Methods Participants in the Black Women’s Health Study, a prospective cohort of 59,000 African American women, reported birth weight, preterm birth, twin or triplet status, maternal age at birth, birth order, and having been breastfed during infancy at various times during follow-up from 1997 to 2015. Numbers of incident cases ranged from 312 for breastfed analyses to 1,583 for twin or triplet analyses. Using multivariable Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between each factor and breast cancer risk overall and by estrogen receptor (ER) status. Results Compared to birth weights of 5 lbs. 8 oz.–8 lbs. 13 oz., low (< 5 lbs. 8 oz.) and high (> 8 lbs. 13 oz.) birth weights were associated with increased breast cancer risk; HRs (95% CI) were 1.19 (0.98–1.44) and 1.26 (0.97–1.63), respectively. Associations were similar by ER status. Having been born to a mother aged ≥ 35 years versus < 20 years was associated with risk of ER+ (HR 1.59, 95% CI 1.10–2.29), but not ER− breast cancer. Other perinatal factors were not associated with breast cancer. Conclusion African American women with a low or high birth weight or born to older mothers may have increased breast cancer risk. Trends towards delayed child birth and higher birth weights, coupled with disproportionately high rates of low birth weight among African Americans, may contribute to increases in breast cancer incidence.