Table 3.

Quality assessment using EPHPP quality rating

Author, year	Selection bias	Study design	Blinding	Confounders	Data collection methods	Withdrawal /dropouts	Study quality
Ki, 2021 [24]	Moderate	Strong	Weak	Moderate	Moderate	Strong	Weak
Lee, 2021 [25]	Moderate	Strong	Weak	Weak	Strong	Strong	Weak
Sun, 2021 [36]	Moderate	Moderate	Strong	Weak	Strong	Strong	Moderate
Lee, 2020 [33]	Moderate	Moderate	Weak	Weak	Strong	Strong	Moderate
Shokouhi, 2020 [30]	Weak	Strong	Strong	Moderate	Strong	Strong	Moderate
Keyong, 2019 [23]	Strong	Strong	Strong	Weak	Moderate	Strong	Moderate
Tellez, 2019 [31]	Strong	Strong	Weak	Strong	Strong	Strong	Moderate
Schwindling, 2018 [42]	Strong	Strong	Weak	Strong	Strong	Moderate	Moderate
Seleskog, 2018 [43]	Weak	Strong	Strong	Strong	Moderate	Strong	Moderate
Marino, 2016 [34]	Moderate	Moderate	Weak	Weak	Moderate	Weak	Weak
Khanagar, 2015 [40]	Strong	Strong	Weak	Moderate	Strong	Strong	Moderate
Ohara, 2015 [26]	Strong	Strong	Weak	Weak	Strong	Strong	Weak
Saengtipbovorn, 2015 [28]	Moderate	Strong	Weak	Weak	Strong	Strong	Weak
Khanagar, 2014 [39]	Strong	Strong	Weak	Moderate	Strong	Strong	Moderate
Saengtipbovorn, 2014 [35]	Moderate	Moderate	Moderate	Strong	Strong	Weak	Moderate
MacEntee, 2007 [41]	Strong	Moderate	Strong	Weak	Strong	Strong	Moderate
Zhang, 2007 [32]	Moderate	Strong	Strong	Weak	Moderate	Strong	Moderate
Nicol, 2005 [44]	Moderate	Moderate	Strong	Weak	Strong	Strong	Moderate
Frenkel, 2002 [37]	Strong	Strong	Strong	Moderate	Weak	Weak	Weak
Frenkel, 2001 [38]	Strong	Strong	Strong	Moderate	Weak	Strong	Moderate
Powell, 1999 [27]	Moderate	Strong	Moderate	Weak	Strong	Strong	Moderate
Paulsson, 1998 [45]	Strong	Moderate	Weak	Weak	Strong	Moderate	Weak
Schou, 1989 [29]	Strong	Strong	Strong	Weak	Weak	Weak	Weak