Table 3. Newcastle-Ottawa scale (NOS) to assess the quality of non-randomised studies.

 

 

Study	Selection	Comparability	Outcome/Exposure
Al-Aroomi et al. (2023) [9]	****	*	**
Zuidam et al. (1997) [16]	****	**	***
Vahldieck et al. (2022) [15]	****	*	**
Chambers et al. (1997) [10]	***	*	*
Davies et al. (2011) [11]	****	*	***
Krane et al. (2020) [12]	****	*	***
Peter et al. (2021) [13]	****	*	***