Association of Reproductive and Menstrual Characteristics with Mammographic Density

Mammographic density has been recognized as a risk factor for breast cancer, but the association between potential effective factors and mammographic density has not been fully studied in Asian women. We conducted a study to investigate the association of mammographic breast density with several menstrual and reproductive characteristics. Screening mammography was performed in women above 40 years attending the breast clinic of Arash Women’s Hospital, Tehran, Iran, for breast cancer screening. The densities were classified by two expert radiologists according to the parenchymal mammographic classification system of the American College of Radiologists. Those with a history of breast cancer or renal disease, recent hormone replacement therapy, or consumption of vitamin D supplements were excluded. Overall, 823 patients were assessed. Mammographic density was associated with higher age at first birth (P < 0.001), lower parity (P < 0.001), BMI (P < 0.001), and premenopausal status (P < 0.001). However, no associations were observed with age at menarche (P = 0.057) and menstrual pattern (P = 0.973). Our study showed an association between mammographic density and age, parity, BMI, and age at first birth, and no association with menstrual pattern in terms of regularity and age at menarche. In addition, mammographic density was significantly higher in premenopausal women.