title: Cancer risk among people with type 1 and type 2 diabetes: disentangling true associations, detection bias, and reverse causation.
abstract: OBJECTIVE
  Evidence indicates an increased risk of certain cancers among people with type 2 diabetes. Evidence for rarer cancers and for type 1 diabetes is limited. We explored the excess risk of site-specific cancer incidence and mortality among people with type 1 and type 2 diabetes, compared with the general Australian population.
  
  
  METHODS
  Registrants of a national diabetes registry (953,382) between 1997 and 2008 were linked to national death and cancer registries. Standardized incidence and mortality ratios (SIRs/SMRs) are reported.
  
  
  RESULTS
  For type 1 diabetes, significant elevated SIRs were observed for pancreas, liver, esophagus, colon and rectum (females only [F]), stomach (F), thyroid (F), brain (F), lung (F), endometrium, and ovary, and decreased SIRs were observed for prostate in males. Significantly increased SMRs were observed for pancreas, liver, and kidney (males only), non-Hodgkin's lymphoma, brain (F), and endometrium. For type 2 diabetes, significant SIRs were observed for almost all site-specific cancers, with highest SIRs observed for liver and pancreas, and decreased risks for prostate and melanoma. Significant SMRs were observed for liver, pancreas, kidney, Hodgkin's lymphoma, gallbladder (F), stomach (F), and non-Hodgkin's lymphoma (F). Cancer risk was significantly elevated throughout follow-up time but was higher in the first 3 months postregistration, suggesting the presence of detection bias and/or reverse causation.
  
  
  CONCLUSIONS
  Type 1 and type 2 diabetes are associated with an excess risk of incidence and mortality for overall and a number of site-specific cancers, and this is only partially explained by bias. We suggest that screening for cancers in diabetic patients is important.
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia jessica.harding@bakeridi.edu.au.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Harding
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Shaw
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Peeters
authors.affiliation: Department of Clinical Epidemiology, Steno Diabetes Center, Copenhagen, Denmark.
authors.forename: Bendix
authors.initials: B
authors.lastname: Cartensen
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: Dianna J
authors.initials: DJ
authors.lastname: Magliano
mesh_terms: D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology*; D055815:Young Adult