title: Aspirin use and lung cancer risk: a possible relationship? Evidence from an updated meta-analysis.
abstract: OBJECTIVE
  Growing evidence has emerged and controversial results reported on possible relationship between aspirin use and lung cancer risk. We, therefore, conducted this updated and comprehensive meta-analysis to evaluate this issue, with focus on dose-risk and duration-risk relationships.
  
  
  METHODS
  We searched electronic databases including PUBMED, EMBASE and Cochrane library to identify eligible studies. Relative risk (RR) and its 95% confidence interval (CI) were used for cohort studies, while odds ratio (OR) were employed for case-control studies. The random effects and fixed effects models were used for analyses.
  
  
  RESULTS
  18 studies were identified including 19835 lung cancer cases, which were eligible for inclusion in the present meta-analysis. Pooled data from case-control studies showed a significant inverse association between regular aspirin use and lung cancer risk. But for cohort studies, insignificant association was detected with little evidence of heterogeneity (RR: 1.05, 95%CI: 0.95 - 1.16; I2: 10.3%, p value: 0.351). In case-control studies, standard aspirin use (>325mg) was related to lower lung cancer incidence, compared with low-dose aspirin use (75-100mg). A similar trend was observed in cohort studies. Besides, when analysis was restricted to long time regular aspirin use (>5 years), insignificant results were reported in both cohort and case-control studies. Finally, regular aspirin use might result in higher reduction of non-small cell lung cancer incidence among men.
  
  
  CONCLUSIONS
  Our findings do not support the protective effect of regular aspirin use on lung cancer risk. Long time aspirin use, sex, dose and type of lung cancer might alter the effect of aspirin use on lung cancer risk. More well-designed studies are needed to further clarify these associations.
authors: Electrocardiographic room, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
authors: Hai-yan
authors: HY
authors: Jiang
authors: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of First Clinical Medical College, Nanjing Medical University, Nanjing, Jiangsu, China.
authors: Tian-bao
authors: TB
authors: Huang
authors: Department of First Clinical Medical College, Nanjing Medical University, Nanjing, Jiangsu, China; Department of respiratory medicine, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
authors: Lei
authors: L
authors: Xu
authors: Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
authors: Jing
authors: J
authors: Yu
authors: Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
authors: Yan
authors: Y
authors: Wu
authors: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China.
authors: Jiang
authors: J
authors: Geng
authors: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China; Department of First Clinical Medical College, Nanjing Medical University, Nanjing, Jiangsu, China.
authors: Xu-dong
authors: XD
authors: Yao
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology* / Q000627:therapeutic use; D016588:Anticarcinogenic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001241:Aspirin / Q000494:pharmacology* / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000517:prevention & control*; D016022:Case-Control Studies; D006801:Humans; D008175:Lung Neoplasms / Q000139:chemically induced*; D018570:Risk Assessment; D017678:Sex Distribution
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016588:Anticarcinogenic Agents; D001241:Aspirin