Age, Hormonal Factors and Family History Influence Risk of Benign Breast Disease: Study

Menarche, duration of menstrual cycles, BMI at menopause, use of oral contraceptives and Hormone Replacement Therapy, and breast-feeding duration are some of the factors that are known to influence the risk of BBDs and Breast Cancer. In addition to this, history of BBDs are also associated with a higher Breast Cancer risk. However, reliable data pertaining to the risk factors of BBDs and its association with age, hormonal factors and risk of breast cancer does not exist.

With this background, researchers at the Karolinska Institute in Stockholm, Sweden collaborated with the University of California and the Buck Institute for Research on Aging, California, to investigate the risk of BBDs by age, hormonal factors, and family history of breast cancer.

They performed a retrospective cohort study that assessed 70 877 women who attended mammographic screening or underwent clinical mammography from January 1, 2011, to March 31, 2013, at 4 Swedish hospitals. The participants were selected through the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA), which is a well-recognized screening cohort, and were made to fill a comprehensive web-based questionnaire. Pathology medical records on breast biopsies were obtained for the participants and all participants had complete follow-up through high-quality Swedish national registers until December 31, 2015.

The study showed some interesting results:

Incidence rates and risk estimates varied by age and BBD subtype.

At premenopausal ages, nulliparity was associated with reduced risk of epithelial proliferation without atypia (EP; HR, 0.62; 95% CI, 0.46-0.85) but increased risk of cysts (HR, 1.38; 95% CI, 1.03-1.85).

Current and long oral contraceptive use was associated with reduced premenopausal risk of fibroadenoma (HR, 0.65; 95% CI, 0.47-0.90)

Hormone replacement therapy was associated with increased postmenopausal risks of epithelial proliferation with atypia (EPA; HR, 1.81; 95% CI, 1.07-3.07), fibrocystic changes (HR, 1.60; 95% CI, 1.03-2.48), and cysts (HR, 1.98; 95% CI, 1.40-2.81).

At premenopausal ages, obesity was associated with reduced risk of several BBDs (eg, EPA: HR, 0.31; 95% CI, 0.17-0.56).

Family history of breast cancer was associated with increased risk (eg, EPA: HR, 2.11; 95% CI, 1.48-3.00)

"These results suggest that the risk of BBDs varies by subtype, hormonal factors, and family history of breast cancer and is influenced by age. However, a better understanding of BBDs is important to improve the understanding of benign and malignant breast diseases," the research team concluded.

Reference:

Study titled, "Characterization of Benign Breast Diseases and Association With Age, Hormonal Factors, and Family History of Breast Cancer Among Women in Sweden," published in Journal of American Medical Association.

DOI: 10.1001/jamanetworkopen.2021.14716