Table 3.

Risk of bias assessment for included studies

Author (year); Country
Randomized controlled trials	Selection bias	Performance bias	Detection bias	Attrition bias	Reporting bias	Other bias
de Jonghe (2014); The Netherlands [29]	Low	Low	Low	High	Low	Low
Nickkholgh (2011); Germany [32]	Low	Low	High	Low	Unclear	Unclear
Sultan (2010); Egypt [33]	Unclear	Low	Unclear	Unclear	Low	Low
Yamaguchi (2014); Japan [34]	Unclear	Unclear	Unclear	Unclear	Low	Unclear
Observational studies	Bias due to confounding	Bias in selection of participants into the study	Bias in classification of interventions	Bias due to deviations from intended interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported results
Artemiou (2015); Slovakia [30]	Moderate	Low	Low	Low	Low	Moderate	Low
Miyata (2017); Japan [31]	Moderate	No information	Low	Low	Low	Low	Low