2026-05-22T17:22:33Zhttps://repisalud.isciii.es/rest/oai/request

oai:repisalud.isciii.es:20.500.12105/72572025-05-05T11:15:26Zcom_20.500.12105_2052com_20.500.12105_2051col_20.500.12105_19608

00925njm 22002777a 4500 dc Lope Carvajal, Virginia author Perez-Gomez, Beatriz author Sánchez-Contador, Carmen author Santamariña, María Carmen author Moreo, Pilar author Vidal, Carmen author Laso, María Soledad author Ederra, María author Pedraz-Pingarrón, Carmen author González-Román, Isabel author García-López, Milagros author Salas-Trejo, Dolores author Peris, Mercé author Moreno, María Pilar author Vázquez-Carrete, Jose Antonio author Collado, Francisca author Aragones, Nuria author Pollan-Santamaria, Marina author 2012-01-04 High mammographic density (MD) is used as a phenotype risk marker for developing breast cancer. During pregnancy and lactation the breast attains full development, with a cellular-proliferation followed by a lobular-differentiation stage. This study investigates the influence of obstetric factors on MD among pre- and post-menopausal women. We enrolled 3,574 women aged 45-68 years who were participating in breast cancer screening programmes in seven screening centers. To measure MD, blind anonymous readings were taken by an experienced radiologist, using craniocaudal mammography and Boyd's semiquantitative scale. Demographic and reproductive data were directly surveyed by purpose-trained staff at the date of screening. The association between MD and obstetric variables was quantified by ordinal logistic regression, with screening centre introduced as a random effect term. We adjusted for age, number of children and body mass index, and stratified by menopausal status. Parity was inversely associated with density, the probability of having high MD decreased by 16% for each new birth (P value < 0.001). Among parous women, a positive association was detected with duration of lactation [>9 months: odds ratio (OR) = 1.33; 95% confidence interval (CI) = 1.02-1.72] and weight of first child (>3,500 g: OR = 1.32; 95% CI = 1.12-1.54). Age at first birth showed a different effect in pre- and post-menopausal women (P value for interaction = 0.030). No association was found among pre-menopausal women. However, in post-menopausal women the probability of having high MD increased in women who had their first child after the age of 30 (OR = 1.53; 95% CI = 1.17-2.00). A higher risk associated with birth of twins was also mainly observed in post-menopausal women (OR = 2.02; 95% CI = 1.18-3.46). Our study shows a greater prevalence of high MD in mothers of advanced age at first birth, those who had twins, those who have breastfed for longer periods, and mothers whose first child had an elevated birth weight. These results suggest the influence of hormones and growth factors over the proliferative activity of the mammary gland. Breast Cancer Res Treat. 2012; 132(3): 1137–1146. 10.1007/s10549-011-1936-x 1573-7217 0167-6806 Breast Cancer Research and Treatment 22215386 http://hdl.handle.net/20.500.12105/7257 Mammographic density Obstetric history Age at first birth Lactation Obstetric history and mammographic density: a population-based cross-sectional study in Spain (DDM-Spain)