- Risk of bias assessment for cohort study using Ottawa-Newcastle score.
| No. | Study | Selection | Comparability | Outcome | Total score | Abstract or full article |
|---|---|---|---|---|---|---|
| 1 | Zanella et al 1986 | ** | * | ** | 5 | full article |
| 2 | Tagariello et al 2006 | **** | * | *** | 8 | full article |
| 3 | Magnussen et al 2011 | **** | * | *** | 8 | Full article |
| 4 | Al-Rubaie et al 2014 | *** | * | *** | 7 | full article |
| 5 | Olkhovskiy et al 2015 | **** | ** | *** | 9 | Full article |
| 6 | Kamaruzzaman et al 2018 | *** | * | *** | 7 | full article |
| 7 | Kandasamy et al 2019 | ** | * | *** | 6 | full article |
| 8 | Gadaam et al 2022 | **** | * | *** | 7 | full article |
| 9 | Sidon et al 2006 | *** | ** | *** | 8 | Abstract/letter |
| 10 | Bianchi et al 2007 | *** | * | *** | 7 | Abstract |
| 11 | Hopkin et al 2007 | **** | ** | *** | 9 | Abstract |