Table 4.

Newcastle-Ottawa scale of the included studies

Study	Selection†	Comparability‡	Outcome§
Rodriguez et al	3	1	2
Williams et al	3	1	3
Pelargonio et al	3	1	3
Kempa et al	3	1	2
Kutarski et al	3	2	3
El-Chami et al	3	1	3
Yagishita et al	3	1	3

^†Maximum 4 stars.

^‡Maximum 2 stars.

^§Maximum 3 stars.