Table 1

Designs of studies included in the present meta-analysis

1st author, yearStudy typeRegionSource populationTotal participants (events)Follow-up (years)Confounding adjustment
Yang, 2004 (6)Nested case-control studyU.K.A cohort of patients with type 2 diabetes in the General Practice Research Database from 1987 to 200224,918 (125)5.6*Sex, history of cholecystectomy, smoking, duration of type 2 diabetes, BMI, 3 or more years of sulfonylurea use prior to index date, 1 or more years of recent NSAID/aspirin use
Chung, 2008 (23)Case-control studyKoreaA cohort of patients with type 2 diabetes without colorectal adenoma from 2003 to 2006200 (100)Matching on age (± 1 year) and sex, adjusting with age, sex, BMI, diabetes duration, HbA1c, lipids, insulin, aspirin
Libby, 2009 (17)Retrospective cohort studyScotland, U.K.A cohort of patients with type 2 diabetes in Tayside, Scotland, U.K. from 1994 to 20038,000 (116)Open cohort, Jan 1994–Dec 2003Sex, age, BMI, HbA1c, deprivation, smoking, other drug use
Currie, 2009 (18)Retrospective cohort studyU.K.A cohort of diabetes patients (diagnosed >40 years of age) in The Health Information Network, after 200259,609 (292)2.4Age, sex, smoking status, and a diagnosis of a prior cancer
Lee, 2011 (27)Retrospective cohort studyTaiwan, ChinaA cohort of participants ≥20 years, diabetes-cancer-free in Jan 200015,434 (56)3.5Age, sex, other oral antihyperglycemic medication, CCI score
  • *Mean follow-up for the 125 cases. CCI, Charlson Comorbidity Index; NSAID, nonsteroidal anti-inflammatory drug.