Table 5.

Results of risk-of-bias assessment for cross-sectional studies, according to the current version of the Newcastle–Ottawa assessment scale.

Study	Selection	Comparability	Outcome	Overall
Wu, Y.-H. et al. [33]	5	1	3	9 (High Quality)
Bahramian, A. et al. [34]	4	1	3	8 (High Quality)
Hugar, S. et al. [13]	3	1	3	7 (High Quality)
Kim, I.-J. et al. [35]	5	1	2	8 (High Quality)
Gyll, J. et al. [36]	5	1	3	9 (High Quality)
Munday, M.-R. et al. [13]	5	1	2	8 (High Quality)
Nuszkiewicz, J. et al. [37]	4	1	2	7 (High Quality)