title: The risk of colorectal cancer in patients with type 2 diabetes: associations with treatment stage and obesity.
abstract: OBJECTIVE
  To assess the risk of colorectal cancer associated with type 2 diabetes, as compared with a nondiabetic reference population, and to study additional associations between treatment stage and duration of obesity and colorectal cancer risk.
  
  
  METHODS
  We conducted an observational population-based cohort study within the Clinical Practice Research Datalink (1987-2012). All patients (≥18 years) with at least one prescription for an antidiabetic drug (n = 300,039) were matched (1:1) by birth year, sex, and practice to a comparison cohort without diabetes. Cox proportional hazards models were used to derive adjusted hazard ratios (HRs) for colorectal cancer associated with type 2 diabetes. Within the diabetic cohort, associations of colorectal cancer with treatment stages and duration of obesity (BMI ≥30 kg/m(2)) were studied.
  
  
  RESULTS
  After a median follow-up of 4.5 years, 2,759 cases of colorectal cancer were observed among the diabetic study population. Type 2 diabetes was associated with a 1.3-fold increased risk of colorectal cancer (HR 1.26 [95% CI 1.18-1.33]). Among diabetic patients, no association was found with treatment stages. A trend of increased colorectal cancer risk was observed with longer duration of obesity. Risk of colorectal cancer was significantly increased for patients with recorded duration of obesity of 4-8 years (HR 1.19 [1.06-1.34]) and >8 years (1.28 [1.11-1.49]).
  
  
  CONCLUSIONS
  Type 2 diabetes is associated with a moderately increased risk of colorectal cancer. Among diabetic patients, an increased risk was observed for patients who suffered from obesity for a total duration of 4 years or more.
authors.affiliation: Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Paul J H L
authors.initials: PJ
authors.lastname: Peeters
authors.affiliation: Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Marloes T
authors.initials: MT
authors.lastname: Bazelier
authors.affiliation: Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Hubert G M
authors.initials: HG
authors.lastname: Leufkens
authors.affiliation: Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, U.K. Department of Clinical Pharmacy and Toxicology, Maastricht University Medical Centre, Maastricht, the Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: de Vries
authors.affiliation: Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands m.l.debruin@uu.nl.
authors.forename: Marie L
authors.initials: ML
authors.lastname: De Bruin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D007004:Hypoglycemic Agents