title: Can aspirin reduce the risk of colorectal cancer in people with diabetes? A population-based cohort study.
abstract: OBJECTIVE
  To evaluate whether aspirin can reduce the risk of colorectal cancer in people with diabetes.
  
  
  METHODS
  We studied ≥ 30-year-old people with diabetes, included in the Longitudinal Health Insurance Database 2005 in Taiwan, who were treated with hypoglycaemic drugs. We used a time-varying Cox regression model to adjust for immortal time bias and to estimate the adjusted hazard ratio and 95% CI for the association between aspirin use and colorectal cancer occurrence.
  
  
  RESULTS
  We studied a total of 60 828 people with diabetes (31 176 men and 29 652 women). Their mean (sd) age was 58.72 (13.33) years. A total of 26 494 people were taking aspirin. Aspirin use 3-5 times/week (moderate frequency) for > 5 years (long duration) was found to reduce the risk of colorectal cancer by 46% (hazard ratio 0.54, 95% CI 0.34-0.86). Aspirin use > 5 times/week (high frequency) for 4-5 years (moderate duration) and > 5 years reduced the risk of colorectal cancer by 56 and 68%, respectively (hazard ratio 0.44, 95% CI 0.24-0.80; hazard ratio 0.32, 95% CI 0.20-0.50). Low frequency (≤ 2 times/week) and/or short duration (≤ 3 years) of aspirin use did not reduce the risk of colorectal cancer.
  
  
  CONCLUSIONS
  Aspirin use with high frequency and long duration reduced the risk of colorectal cancer in people with diabetes in a frequency- and duration-dependent manner, whereas low frequency and/or short duration of aspirin use did not. The dosage, frequency and duration of aspirin use that are sufficient to prevent the incidence of colorectal cancer in people with diabetes require further study.
authors.affiliation: Department of Family Medicine, Wan Fang Hospital, Taipei Medical University, Taipei; Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei.
authors.forename: C C
authors.initials: CC
authors.lastname: Lin
authors.forename: M S
authors.initials: MS
authors.lastname: Lai
authors.forename: W Y
authors.initials: WY
authors.lastname: Shau
mesh_terms: D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001241:Aspirin / Q000627:therapeutic use*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D048909:Diabetes Complications / Q000150:complications*; D003920:Diabetes Mellitus / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007004:Hypoglycemic Agents; D001241:Aspirin