The risk of colorectal cancer in patients with type 2 diabetes: associations with treatment stage and obesity

Diabetes Care. 2015 Mar;38(3):495-502. doi: 10.2337/dc14-1175. Epub 2014 Dec 31.


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.

Research design and 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.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • Colorectal Neoplasms / epidemiology
  • Colorectal Neoplasms / etiology*
  • Diabetes Mellitus, Type 2 / complications*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / pathology
  • Disease Progression
  • Female
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Incidence
  • Male
  • Middle Aged
  • Obesity / complications*
  • Obesity / drug therapy
  • Obesity / epidemiology
  • Retrospective Studies
  • Risk Factors
  • Time Factors
  • Young Adult


  • Hypoglycemic Agents