Relation between diabetes, metformin treatment and the occurrence of malignancies in a Belgian primary care setting

Diabetes Res Clin Pract. 2012 Aug;97(2):331-6. doi: 10.1016/j.diabres.2012.02.002. Epub 2012 Mar 2.


Background: Associations between type 2 diabetic patients and a higher risk of developing cancer have been reported worldwide. Recently, a protective effect of metformin has been described.

Aim: To examine in the Belgian primary care population the relation between presence of type 2 diabetes with and without metformin treatment and the occurrence of malignancies.

Design of study: Retrospective cohort study, based on the Intego database, an ongoing Belgian general practice-based morbidity registry, covering 90 general practitioners and including about 1.5 million patient-years between 1994 and 2008.

Method: Cox proportional hazard analysis comparing emergence of malignancy in patients with and without type 2 diabetes, and among patients with diabetes comparing emergence of malignancy in those treated with various antidiabetic drugs.

Results: Malignancies occurred more in type 2 diabetic patients compared to non-diabetic controls (HR=1.84; 95% CI=1.51-2.24), adjusted for age, gender and weight. Treatment with both metformin and 'other' antidiabetic agents was related to decreased cancer risk (HR=0.24 and 0.22) compared to diet only in men but not in women.

Conclusion: In this Belgian primary care setting, diabetic patients have higher cancer prevalences than non-diabetic patients. Moreover, in diabetic men, not only metformin but also other antidiabetic agents were associated with lower cancer risks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Belgium / epidemiology
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / drug therapy
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diabetes Mellitus, Type 2 / pathology
  • Diet / statistics & numerical data*
  • Female
  • Humans
  • Hypoglycemic Agents / administration & dosage
  • Hypoglycemic Agents / therapeutic use*
  • Life Style
  • Male
  • Metformin / administration & dosage
  • Metformin / therapeutic use*
  • Middle Aged
  • Neoplasms / drug therapy
  • Neoplasms / epidemiology*
  • Neoplasms / pathology
  • Neoplasms / prevention & control*
  • Prevalence
  • Primary Health Care / statistics & numerical data*
  • Probability
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Factors


  • Hypoglycemic Agents
  • Metformin