The Results of Quality Assessment of the Included Studies
| Article | Level of evidence | Reporting | External validity | Internal validity (bias) | Internal validity (confounding) | Total score |
|---|---|---|---|---|---|---|
| Ahn et al., 201710) | 3 | 8 | 2 | 5 | 2 | 17 |
| Radler et al., 201011) | 3 | 7 | 0 | 5 | 2 | 14 |
| Bosmans et al, 201614) | 4 | 5 | 1 | 4 | 2 | 13 |
| Cimolin et al., 201025) | 4 | 8 | 2 | 5 | 1 | 16 |
| Heller et al., 200118) | 3 | 5 | 0 | 5 | 1 | 11 |
| Redmond, 199820) | 2 | 5 | 2 | 5 | 2 | 14 |
| Abd, 201423) | 1 | 9 | 2 | 7 | 4 | 22 |
| Bruderer-Hofstetter et al., 201512) | 4 | 8 | 1 | 5 | 1 | 15 |
| Nyland et al., 200413) | 4 | 7 | 0 | 4 | 3 | 14 |
| Karabicak et al., 201615) | 3 | 8 | 2 | 5 | 3 | 18 |
| Carriero et al., 200916) | 3 | 7 | 0 | 5 | 1 | 13 |
| Carriero et al., 201117) | 4 | 5 | 0 | 5 | 2 | 12 |
| Amichai et al., 200919) | 3 | 8 | 2 | 4 | 2 | 16 |
