title: Metformin and the risk of head and neck cancer: a case-control analysis.
abstract: OBJECTIVE
  Metformin use has been associated with a decreased risk of some cancers, although data on head and neck cancer (HNC) are scarce. We explored the relation between the use of antidiabetic drugs and the risk of HNC.
  
  
  METHODS
  We conducted a case-control analysis in the UK-based Clinical Practice Research Datalink (CPRD) of people with incident HNC between 1995 and 2013 below the age of 90 years. Six controls per case were matched on age, sex, calendar time, general practice and number of years of active history in the CPRD prior to the index date. Other potential confounders including body mass index (BMI), smoking, alcohol consumption and comorbidities were also evaluated. The final analyses were adjusted for BMI, smoking and diabetes mellitus (or diabetes duration in a sensitivity analysis). Results are presented as odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  Use of metformin was neither associated with a statistically significant altered risk of HNC overall (1-29 prescriptions: adjusted OR 0.87, 95% CI 0.61-1.24 and ≥ 30 prescriptions adjusted OR 0.80, 95% CI 0.53-1.22), nor was long-term use of sulphonylureas (adjusted OR 0.87, 95% CI 0.59-1.30), or any insulin use (adjusted OR 0.92, 95% CI 0.63-1.35). However, we found a (statistically non-significant) decreased risk of laryngeal cancer associated with long-term metformin use (adjusted OR 0.41, 95% CI 0.17-1.03).
  
  
  CONCLUSIONS
  In this population-based study, the use of antidiabetic drugs was not associated with a materially altered risk of HNC. Our data suggest a protective effect of long-term metformin use for laryngeal cancer.
authors.affiliation: Basel Pharmacoepidemiology Unit, Division of Clinical Pharmacy and Epidemiology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Becker
authors.forename: S S
authors.initials: SS
authors.lastname: Jick
authors.forename: C R
authors.initials: CR
authors.lastname: Meier
authors.forename: M
authors.initials: M
authors.lastname: Bodmer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000401:mortality; D005260:Female; D006258:Head and Neck Neoplasms / Q000139:chemically induced* / Q000401:mortality; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008687:Metformin / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D015398:Signal Transduction; D012907:Smoking; D058570:TOR Serine-Threonine Kinases; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases
keywords: antidiabetic drug; diabetes mellitus; metformin; observational study; pharmacoepidemiology