Table 2:
Investigator (review) | Study design | Eligibility criteria | Country | Study period | Total sample size | Source of funding | Study quality |
---|---|---|---|---|---|---|---|
Brown et al., 201520 (review 1) | Retrospective cohort |
|
United States | 17 yr (Oct. 1, 1996, to Sept. 30, 2013) | 5135 | Authors employed by VHA No grant or commercial funding |
Fair* |
Gooren et al., 201321 (review 1) | Retrospective cohort |
|
The Netherlands | 38 yr (1975 to Dec. 31, 2012) | 3102 | Two authors received noncommercial support | Fair* |
Weyers et al., 201023 (review 2) | Cross-sectional |
|
Belgium | 4 mo (Mar–June 2007) | 50 | First author received commercial support | Poor† |
Kuroda et al., 200822 (review 1) | Retrospective cohort |
|
Japan | 9 yr (1998–2006) | 186 | NR | Poor* |
Note: NR = not reported, VHA = Veterans Health Administration.
Assessed with the Newcastle–Ottawa Scale.16,33 Detailed results of the quality assessment are provided in Supplementary Table S2, Appendix 4 (available at www.cmajopen.ca/content/7/3/E598/suppl/DC1).
No formal critical appraisal tool was used; methodological quality was assessed by considering key methodological components such as the selection of participants, and exposure and outcome assessments.
Detailed results of the quality assessment are provided in Supplementary Table S3, Appendix 4.