Table 3.

Quality assessment of included studies

Study	Downs checklist	Methodological quality
Kirschniak et al. [16]	9	Low
Albert et al. [17]	9	Low
Manta et al. [18]	10	Moderate/low
Mönkemüller et al. [19]	8	Low
Chan et al. [11]	10	Moderate/low
Skinner et al. [12]	10	Moderate/low
Manno et al. [20]	10	Moderate/low
Wedi et al. [21]	9	Low
Richter-Schrag et al. [22]	15	Moderate
Lamberts et al. [23]	11	Moderate/low
Goenka et al. [24]	9	Low
Wedi et al. [25]	12	Moderate/low
Schmidt et al. [26]	20	High
Asokkumar et al. [27]	14	Moderate/low
Manta et al. [13]	14	Moderate/low
Gölder et al. [28]	17	Moderate