association of reproductive and menstrual characteristics with mammographic density

background: 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. m ethods: 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. results: 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). conclusions: 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.