Study lead author | Study year | Selection | Comparability | Outcome | Overall score (number of stars) |
Rosengren et al 29 | 2009 | **** | ** | 6 | |
Tedrow et al 24 | 2010 | *** | *** | 6 | |
Grundvold et al 23 | 2012 | *** | * | ** | 6 |
Huxley et al 30 | 2014 | **** | *** | 7 | |
Alonso et al 21 | 2015 | ** | * | *** | 6 |
Diouf et al 27 | 2015 | *** | ** | 5 | |
Grundvold et al 22 | 2015 | *** | *** | 6 | |
Johnson et al 25 | 2015 | **** | *** | 7 | |
Berkovitch et al 28 | 2016 | **** | *** | 7 | |
Ball et al 26 | 2018 | **** | ** | 6 |
Scores range from 0 to 9 stars with nine stars equating to the lowest risk of bias.