An increased risk of breast cancer after delayed first parity
Presented at the Fourth Annual Meeting of the American Society of Breast Surgeons, Atlanta, Georgia, April 30–May 4, 2003
Received 3 June 2003; received in revised form 21 June 2003
Abstract
Background
As delayed childbirth increases for socioeconomic and fertility reasons, its impact on breast cancer risk needs definition.
Methods
From 1975 to 1981, 1,307 women with childbirth at ≥40 years of age were identified. They were divided into four groups by estimated first birth median ages (EFBMA): 23, 34, 38, and 41 years, corresponding to previous parity of more than 3, 2 or 3, 1, and zero, respectively. Cancer Registry cross-referencing identified those diagnosed with breast cancer.
Results
Breast cancer developed in 39 women. The EFBMA of 41 years carried a relative risk of 3.7, (95%CI: 1.30 to 10.5) compared with age 23. Odds ratio of breast cancer was 1.08 (95%CI: 1.02 to 1.14) with each year older at first birth and 0.79 (95% CI: 0.67 to 0.93) for each additional previous birth.
Conclusions
Increased breast cancer risk with advancing maternal age at first childbirth is supported by 3.7 relative risk in women with an EFBMA of 41 years compared with those with an EFBMA of 23 years.
aThe Breast Health Center, Program in Women's Oncology, Women and Infants' Hospital of Rhode Island, Brown University School of Medicine, Providence, RI, USA
bDepartment of Surgery, Brown University School of Medicine, Providence, RI, USA
cDepartment of Obstetrics and Gynecology, Division of General Obstetrics and Gynecology, Tufts-New England Medical Center, Boston, MA, USA
dRhode Island Department of Health, Providence, RI, USA
eUniversity Surgical Associates-APC 120, 593 Eddy St., Providence, RI 02903, USA
ABSTRACT