Table 2.

Risk of bias summary.

Study, year	Domain 1: risk of bias arising from the randomization process	Domain 2: risk of bias because of deviations from the intended interventions	Domain 3: missing outcome data	Domain 4: risk of bias in the measurement of the outcome	Domain 5: risk of bias in selection of the reported result	Overall risk of bias
Evans et al, 2012 [31]	High	High	High	Some concerns	Low	High
Pollak et al, 2014 [32]	High	Low	Low	Some concerns	Low	High
Evans et al, 2015 [38]	Low	Low	Low	Some concerns	Low	Some concerns
Smith et al, 2016 [39]	Low	High	High	High	Low	High
Choi et al, 2016 [33]	Low	Low	Low	Low	Low	Low
Willcox et al, 2017 [34]	Low	Some concerns	Low	Some concerns	Low	Some concerns
Redman et al, 2017 [35]	Low	Low	Low	Low	Low	Low
Hayman et al, 2017 [36]	Low	High	High	Low	Low	High
Huberty et al, 2017 [40]	Some concerns	Low	Low	Low	Low	Some concerns
Olson et al, 2018 [41]	Low	Low	Low	Low	Low	Low
Dahl et al, 2018 [37]	Some concerns	High	High	Some concerns	Low	High