Table 2.

Risk of bias assessment using the Downs and Black [27] tool.

Author et al.	Reporting (Range: 2–12)	External Validity (Range: 0–2)	Bias (Range: 0–6)	Confounding (Range: 1–6)	Power (Range: 0–1)	Total	Final Assessment
Borilova Linhartova et al. [14]	4	1	0	2	0	7	High
López et al. [15]	6	1	2	3	0	12	High
Kavitha et al. [16]	4	1	2	2	0	9	High
Deppe et al. [17]	8	4	4	5	1	22	Low
Cirelli et al. [18]	5	1	1	0	0	7	High
Petrovic et al. [19]	4	1	2	2	0	9	High
Xiao et al. [20]	5	1	1	2	0	9	High
Struch et al. [22]	3	1	1	2	0	7	High