title: Dose-risk and duration-risk relationships between aspirin and colorectal cancer: a meta-analysis of published cohort studies.
abstract: BACKGROUND
  In previous meta-analyses, aspirin use has been associated with reduced risk of colorectal cancer. However, uncertainty remains on the exact dose-risk and duration-risk relationships.
  
  
  METHODS
  We identified studies by searching several English and Chinese electronic databases and reviewing relevant articles. The dose-response meta-analysis was performed by linear trend regression and restricted cubic spline regression. Subgroup analyses were conducted to explore possible heterogeneity among studies. Potential heterogeneity was calculated as Q statistic and I(2) value. Publication bias was evaluated using funnel plots and quantified by the Begg's and Egger's test.
  
  
  RESULTS
  Twelve studies were included in this meta-analysis. An inverse association between aspirin use and colorectal cancer was observed in both the overall group (RR = 0.74, 95% CI 0.64-0.83 for aspirin dose; RR = 0.80, 95% CI 0.75-0.85 for frequency of aspirin use; RR = 0.75, 95% CI 0.68-0.81 for years of aspirin use) and subgroups stratified by sex and cancer site. The dose-response meta-analysis showed that there was a 20% statistically significant decreased risk of colorectal cancer for 325 mg aspirin per day increment, 18% decreased risk for 7 times aspirin per week increment and 18% decreased risk for 10 years aspirin increment.
  
  
  CONCLUSIONS
  Long-term (>5 years), low-dose (75-325 mg per day) and regular aspirin use (2-7 times per week) can effectively reduce the risk of colorectal cancer.
authors: School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, China.
authors: Xiaohua
authors: X
authors: Ye
authors: Jinjian
authors: J
authors: Fu
authors: Yi
authors: Y
authors: Yang
authors: Sidong
authors: S
authors: Chen
mesh_terms: D001241:Aspirin / Q000008:administration & dosage*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D012107:Research Design; D012306:Risk
chemical_list: D001241:Aspirin