However, a more recent analyses among women in general practice databases from Germany and the United Kingdom reported no association between metformin users and breast cancer incidence when compared users of sulfonylurea and insulin (HR = 1.0; 95% CI = 0.8–1.3 and HR = 1.1; 95% CI = 0.7–1.7, respectively) [99]. This evidence concerns the gene INS and breast carcinoma.