title: Relation between diabetes, metformin treatment and the occurrence of malignancies in a Belgian primary care setting.
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Center for Statistics, University of Hasselt, Belgium.
authors.forename: Ngwana
authors.initials: N
authors.lastname: Geraldine
authors.forename: Aerts
authors.initials: A
authors.lastname: Marc
authors.forename: Truyers
authors.initials: T
authors.lastname: Carla
authors.forename: Mathieu
authors.initials: M
authors.lastname: Chantal
authors.forename: Bartholomeeusen
authors.initials: B
authors.lastname: Stefaan
authors.forename: Wami
authors.initials: W
authors.lastname: Welcome
authors.forename: Buntinx
authors.initials: B
authors.lastname: Frank
mesh_terms: D001530:Belgium / Q000453:epidemiology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D004032:Diet / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D008019:Life Style; D008297:Male; D008687:Metformin / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control*; D015995:Prevalence; D011320:Primary Health Care / Q000706:statistics & numerical data*; D011336:Probability; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin