Breast Cancer Research and Treatment

, 98:349

Diabetes mellitus and breast cancer: a retrospective population-based cohort study

  • Lorraine L. Lipscombe
  • Pamela J. Goodwin
  • Bernard Zinman
  • John R. McLaughlin
  • Janet E. Hux
Epidemiology

DOI: 10.1007/s10549-006-9172-5

Cite this article as:
Lipscombe, L.L., Goodwin, P.J., Zinman, B. et al. Breast Cancer Res Treat (2006) 98: 349. doi:10.1007/s10549-006-9172-5

Summary

Purpose

Evidence suggests that women with type 2 diabetes may be at increased risk of breast cancer, possibly due to chronic exposure to insulin resistance and/or hyperinsulinemia. The purpose of this study was to compare the incidence of breast cancer in postmenopausal women with and without diabetes.

Methods

Using population-based validated health databases from Ontario, Canada, this retrospective cohort study compared breast cancer incidence between women, aged 55–79 years, with newly diagnosed diabetes (n=73,796) to women without diabetes (n=391,714).

Results

Women with diabetes were slightly older, were more likely to reside in a lower income neighborhood, had greater comorbidity, and had more annual physician visits than women without diabetes. After 2.2 million person-years of follow-up from 1994 to 2002, breast cancer incidence was 2.97/1000 person-years in the diabetes group and 2.75/1000 person-years in the non-diabetes group. After adjustment for age and income, there was a significant increase in breast cancer among women with diabetes (hazard ratio, HR, 1.08, 95% confidence interval, CI, 1.01–1.16, p=0.021).

Conclusion

This study found a small but significant increase in incident breast cancer in a predominantly postmenopausal population of women with diabetes, when compared to women without diabetes. These results support the possibility that insulin resistance or some other aspect of type 2 diabetes may promote breast cancer, and may further direct treatment and prevention strategies.

Keywords

breast cancercohort studydiabetesepidemiologyinsulin resistancerisk

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Lorraine L. Lipscombe
    • 1
    • 2
    • 4
    • 7
  • Pamela J. Goodwin
    • 2
    • 3
    • 5
    • 6
  • Bernard Zinman
    • 2
    • 5
    • 6
  • John R. McLaughlin
    • 3
    • 6
  • Janet E. Hux
    • 1
    • 2
    • 3
    • 4
  1. 1.Institute for Clinical Evaluative SciencesTorontoCanada
  2. 2.Department of MedicineUniversity of TorontoTorontoCanada
  3. 3.Department of Health Policy, Management and EvaluationUniversity of TorontoTorontoCanada
  4. 4.Sunnybrook and Women’s College Health Sciences CenterTorontoCanada
  5. 5.Mount Sinai HospitalTorontoCanada
  6. 6.Samuel Lunenfeld Research InstituteTorontoCanada
  7. 7.Institute for Clinical Evaluative SciencesTorontoCanada