Cohort study | Author (year) | Selection | Comparability | Outcome | Total |
---|
1 | Duggan (2013) [25] | *** | * | ** | 6 |
2 | Ko (2016) [26] | **** | * | *** | 8 |
3 | Lin (2015) [27] | **** | * | ** | 7 |
4 | Lindkvist (2014) [15] | **** | * | *** | 8 |
Case–control study | Author (year) | Selection | Comparability | Exposure | Total |
---|
1 | Drahos (2016) [14] | **** | * | ** | 7 |
2 | Drahos (2017) [24] | **** | * | ** | 7 |