Table 1.
Quality assessment of the included studies.
| Grushka et al. 1987 [43] | Svensson et al. 1993 [45] | Ito et al., 2002 [46] | Lauria et al., 2005 [16] | Yilmaz et al., 2007 [17] | Beneng et al., 2010 [47] | Beneng et al., 2010b [48] | Just et al., 2010 [49] | Penza et al., 2010 [50] | Kaplan et al., 2011 [51] | Mendak et al., 2012 [52] | Borsani et al., 2014 [53] | Mo et al., 2015 [54] | Shinoda et al., 2015 [55] | Puhakka et al., 2016 [40] | Yilmaz et al., 2016 [56] | Hartmann et al., 2017 [57] | O’ Neil et al., 2018 [58] | Kolkka et al., 2019 [59] | Domaneschi et al., 2023 [46] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Criteria | ||||||||||||||||||||
| 1. Was the research question or objective in this paper clearly stated and appropriate? | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y |
| 2. Was the study population clearly specified and defined? | n | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y |
| 3. Did the authors include a sample size justification? | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | y | n | n |
| 4. Were controls selected or recruited from the same or similar population that gave rise to the cases (including the same timeframe)? | nr | y | y | n | y | y | y | y | n | y | y | y | y | y | y | y | y | y | y | y |
| 5. Were the definitions, inclusion and exclusion criteria, algorithms, or processes used to identify or select cases and controls valid, reliable, and implemented consistently across all study participants? | nr | y | y | n | y | y | y | y | cd | y | y | y | y | y | y | y | y | y | y | y |
| 6. Were the cases clearly defined and differentiated from controls? | nr | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y |
| 7. If less than 100 percent of eligible cases and/or controls were selected for the study, were the cases and/or controls randomly selected from those eligible? | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n |
| 8. Was there use of concurrent controls? | y | y | y | y | y | y | y | y | n | y | y | y | y | y | y | y | y | y | y | y |
| 9. Were the investigators able to confirm that the exposure/risk occurred prior to the development of the condition or event that defined a participant as a case? | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y | y |
| 10. Were the measures of exposure/risk clearly defined, valid, reliable, and implemented consistently (including the same time period) across all study participants? | y | y | y | y | y | y | y | y | n | y | y | y | y | y | y | y | y | y | y | y |
| 11. Were the assessors of exposure/risk blinded to the case or control status of participants? | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n | n |
| 12. Were key potential confounding variables measured and adjusted statistically in the analyses? If matching was used, did the investigators account for matching during the study analysis? | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na | na |
| Quality | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f | f |
| Risk of bias % | 67 | 34 | 34 | 50 | 34 | 34 | 34 | 34 | 67 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 25 | 34 | 34 |
y: yes; n: no; nr: not reported; na: not applicable; cd: cannot determine f: fair. Quality is rated as good (<25% risk of bias), fair (26–74% risk of bias), and poor (>75% risk of bias).