Reproductive history and hormonal birth control use are associated with coronary calcium progression in women with type 1 diabetes mellitus

Context: Coronary artery disease is increased in women with type 1 diabetes (T1D), compared with nondiabetic (Non-DM) women. Women with T1D have more menstrual dysfunction and are less likely to use hormonal birth control (BC) than Non-DM women. Objective: The purpose of this study was to determine whether coronary artery calcium (CAC) is associated with menstrual dysfunction and BC use in women with T1D. Materials and Methods: This was a prospective cohort study, and participants were followed up for an average of 2.4 yr. Patients: Patients included 612 women (293 T1D, 319 Non-DM) between the ages of 19 and 55 yr who had CAC measured twice by electron beam tomography. Results: Irregular menses and amenorrhea were more common in T1D than Non-DM women (22.1 vs. 14.9%, P < 0.05 and 16.6 vs. 7.0%, P < 0.001). T1D women reported less BC use than Non-DM women (79.8 vs. 89.9%, P < 0.001) and reached menarche at an older age (13.1 +/- 1.8 vs. 12.8 +/- 1.5 yr, P < 0.05). Use of BC was associated with less CAC progression in all women, but this association was stronger in T1D women (P value for interaction = 0.02). Irregular menses were associated with greater CAC progression only among T1D women. Conclusions: A prior history of BC use is associated with reduced CAC progression among all women, with a stronger association in T1D than in Non-DM women. Women with T1D who report irregular menses have increased CAC progression, compared with those with regular menses.