Does metformin affect mammographic breast density in postmenopausal women with type 2 diabetes

Background: Increased mammographic breast density (MBD) is known to be associated with an increased risk of developing breast cancer.Aims: In this study, we aimed to research the possible relationship between MBD and metformin use in postmenopausal women diagnosed with type 2 diabetes mellitus (T2DM).Method: The patients were divided into two groups: women with T2DM and who were on metformin and women who were newly diagnosed with T2DM and had not yet taken metformin. MBD types are evaluated by a specialist radiologist.Results: Among the 74 women, 32 (43.2%) were in the group that did not use metformin and 42 (56.8%) were in the group of patients using metformin. The duration of breastfeeding (p = .0003), fasting blood glucose (p = .0003) and HbA1c (p = .0006) were statistically significantly higher in the group not using metformin. The quantitative mean ranks of the group members' MBD's were 41.81 in the metformin naïve group and 34.21 in the group using metformin (p = .12).Conclusions: In conclusion, metformin has no statistically significant effect on MBD in postmenopausal female patients with T2DM.