Correlates of mammogram density in southwestern Native-American women.

Little is known about the breast cancer risk factors or mammogram characteristics among Native-American women. Southwestern Native-American women have a low risk of breast cancer and a high risk of diabetes. Our purpose was to determine the prevalence of known clinical risk factors for breast cancer and their association with mammogram density in a sample of Southwestern Native-American women undergoing breast cancer screening. A retrospective review was performed of screening mammogram examinations in 455 women. Density was classified by American College of Radiology Breast Imaging Reporting and Data System (BIRADS) density patterns 1 to 4 (fat to dense). Clinical data including patient age, weight, body mass index, parity, lactation, age at first birth, menopause status, hormone replacement therapy, diabetes status, and family history of breast cancer were obtained. Multivariate analyses were performed. Among the entire group, 152 women (33.4%) had diabetes. Patient age (P = 0.0012), weight (P < 0.0001), menopause status (P = 0.0134), estrogen use (P = 0.0311), age at first birth (P = 0.0035), and diabetes (P = 0.0015) were associated with mammogram density. Diabetes was associated with mammogram density in premenopausal women (P = 0.0032) but not in postmenopausal women (P = 0.3178) in stratified analyses. Diabetes, hormone replacement therapy, age, weight, menopause status, parity, and age at first birth were significantly associated with mammogram density. The association of mammogram density with diabetes varied by menopause status and was significant only for premenopausal women.