3. Quality rating of included studies.
| Study |
Reporting quality range 0 to 11 |
External validity range 0 to 3 |
Internal validity total range 0 to 13 |
Blinding participants |
Blinding outcomes |
Blinding allocation |
Randomised | Adjusted confounding | Adjusted lost follow‐up |
| Burr 2007 | 10 | 2 | 9 | 0 | 0 | 0 | 1 | 1 | 0 |
| Eick 2011 | — | — | — | — | — | — | — | — | — |
| Hoppe 2012 | — | — | — | — | — | — | — | — | — |
| Howden‐Chapman 2007 | 11 | 3 | 8 | 0 | 0 | 0 | 1 | 1 | 1 |
| Jarvis 2001 | 4 | 3 | 4 | 0 | 0 | 0 | 0 | 0 | 0 |
| Kercsmar 2006 | 11 | 1 | 8 | 0 | 0 | 0 | 1 | 0 | 1 |
| Meklin 2005a | — | — | — | — | — | — | — | — | — |
| Meklin 2005b | — | — | — | — | — | — | — | — | — |
| Patovirta 2004a | 7 | 1 | 7 | 0 | 0 | 0 | 0 | 0 | 1 |
| Savilahti 2000 | 11 | 3 | 7 | 0 | 0 | 0 | 0 | 0 | 1 |
| Shortt 2007 | 2 | 1 | 5 | 0 | 0 | 0 | 0 | 0 | 0 |
| Åhman 2000 | 9 | 3 | 7 | 0 | 0 | 0 | 0 | 1 | 1 |
0 = criterion not met 1 = criterion met