Table 3

Breast cancer risk in users of oral antidiabetic drugs and users of insulin

Drug and no. prescriptionsCase patientsControl patientsUnadjusted OR (95% CI)*Adjusted OR (95% CI)P value
n3051,153
Metformin
    None1405401.00 (referent)1.00 (referent)
    1–9642051.21 (0.86–1.72)1.20 (0.82–1.78)0.35
    10–39842881.16 (0.85–1.60)1.09 (0.76–1.55)0.65
    ≥40171200.55 (0.31–0.97)0.44 (0.24–0.82)0.01
Sulfonylureas
    None1384921.00 (referent)1.00 (referent)
    1–9622430.87 (0.61–1.23)0.85 (0.58–1.24)0.39
    10–39712920.87 (0.62–1.20)0.79 (0.55–1.15)0.22
    ≥40341260.96 (0.62–1.49)1.03 (0.62–1.69)0.92
Thiazolidinediones
    none2851,0841.00 (referent)1.00 (referent)
    1–4424
    5–9415
    ≥1012301.59 (0.80–3.17)1.76 (0.84–3.68)0.13
Insulin
    none2621,0221.00 (referent)1.00 (referent)
    1–918491.51 (0.86–2.66)1.74 (0.95–3.21)0.07
    10–2911401.13 (0.57–2.26)1.30 (0.62–2.70)0.49
    ≥3014421.35 (0.72–2.54)1.51 (0.76–3.01)0.24
  • Data are n unless otherwise indicated.

  • *Adjusted for age, sex, general practice, and calendar time by matching.

  • †Adjusted for age, sex, general practice, and calendar time by matching and further adjusted for each other plus use of prandial glucose regulators, acarbose, estrogens, smoking, BMI, diabetes duration, and A1C

  • P values relate to the adjusted model.