title: Age- and sex-specific risks of colorectal cancers in diabetic patients.
abstract: Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies.  However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited.  We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes.  Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006.  The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model.  The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients.  The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years.  Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold).  We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women.  In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years.  Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.
authors.affiliation: Department of Endocrinology, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Hua-Fen
authors.initials: HF
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Chen
authors.forename: Ying-Hwa
authors.initials: YH
authors.lastname: Su
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Su
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Li
mesh_terms: D017677:Age Distribution; D000368:Aged; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D016208:Databases, Factual / Q000706:statistics & numerical data; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009313:National Health Programs / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data