Three studies evaluating metformin use and MBD have found no difference in percent density among patients with diabetes treated with “pills” compared to no treatment, or insulin, [25] an inverse association between diabetes and “mixed/dense breasts” controlled by oral antidiabetic agents compared to diet alone [24], and 5.7% lower percent density for women taking metformin that was attenuated after adjusting for BMI [26]. Here, INS is linked to diabetes mellitus.