Table 2. Scores in each domain of the Newcastle-Ottawa tool assessing the quality of cohort studies.
| Author | PMID | Representativeness | Selection of unexposed | Exposure ascertainment | Free of outcome at baseline | Selection overall | Comparability | Outcome assessment | Follow up duration | Follow up adequacy | Outcome overall | Total score |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Schwartz 2005 | 16243798 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 0 | 2/3 | 8/9 |
| Nose 2011 | 20615575 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Lee 2020 | 31718122 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 0 | 2/3 | 8/9 |
| Ding 2018 | 30013628 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 1 | 3/3 | 8/9 |
| Toh 2010 | 19875972 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 0 | 0 | 1/3 | 7/9 |
| Tanaka 2016 | 27069542 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Kawai 2005 | 16033821 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 1/3 | 7/9 |
| He 2019 | 31289556 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 1 | 3/3 | 8/9 |
| Gao 2019 | 31511014 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| He 2015 | 26137132 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 1 | 3/3 | 8/9 |
| Mah 2011 | 21511357 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Monica 2012 | 22658344 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 1 | 3/3 | 8/9 |
| Navaratam 2012 cohort1 | 22302352 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Navaratam 2012 cohort2 | 22302352 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Skov 2008 | 17905466 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 1 | 3/3 | 9/9 |
| Stabile 2011 | 21062926 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 1 | 3/3 | 9/9 |
| Verma[1] 2012 | 22313325 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Wu 2005 | 16214508 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 1 | 3/3 | 9/9 |
| Yu 2018 | 30250297 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 1 | 3/3 | 8/9 |
| Verma[2] 2012 | 22982181 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Cheng 2018 | 29346580 | 1 | 1 | 1 | 1 | 4/4 | 2/2 | 1 | 1 | 0 | 2/3 | 8/9 |
| Mauro 2010 | 20878128 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
| Enwere | 32676313 | 1 | 1 | 1 | 1 | 4/4 | 1/2 | 1 | 1 | 0 | 2/3 | 7/9 |
Symbols: 1 = good, 0 = not adequate/unclear.