Table 2.

Quality assessment of the included pre-post studies.

First author, year of publication	Selection bias	Study design	Confounders	Blinding	Data collection	Withdrawals	Risk of bias
Everett et al, 2018 [20]	Moderate	Moderate	Weak	Weak	Weak	Strong	High
Kim and Kang, 2013 [21]	Moderate	Moderate	Weak	Weak	Strong	Strong	High
Kim et al, 2014 [22]	Strong	Moderate	Weak	Weak	Strong	Strong	High
Stuckey et al, 2013 [27]	Moderate	Weak	Weak	Weak	Strong	Strong	High