The groups were similar in body mass index (BMI), age, smoking status, proportion of left-sided breast cancer, coronary artery disease, hypertension, and use of aromatase inhibitors (AI), tamoxifen, acetylsalicylic acid (ASA), statins, levothyroxine, diabetes medication, angiotensin converting enzyme (ACE) inhibitors or angiotensin reseptor blockers (ARB) and β-blockers (Additional file 3: Table S3). This evidence concerns the gene CYP19A1 and diabetes mellitus.