Table 3. Risk of bias according to the ROBINS-I tool.
| Study | Confounding | Selection of participants | Classification of intervention | Deviations from intervention | Missing Data | Measurement of outcomes |
|---|---|---|---|---|---|---|
| Suk, 2018 | Serious | Low | Low | Low | Low | Low |
| Wichova, 2018 | Serious | Serious | Unclear | Unclear | Serious | Low |
| De Ridder, 2015 | Serious | Serious | Low | Serious | NA | Low |
| Shim, 2015 | Serious | Low | Low | Low | Low | Low |
| Kreuzer, 2014 | Serious | Serious | Low | Serious | Moderate | Low |
| De Ridder, 2014 | Serious | Low | Low | Low | Moderate | Low |
| Lehtimäki, 2013 | Critical | Unclear | Low | Low | Low | Unclear |