1. Comparison of baseline characteristics of included studies.

ID/Location/Full publication	n randomly assigned/Withdrawals	% female	Mean age (DP)	Asthma diagnosis	Asthma severity
Aranđelović 2007/Serbia/Yes	70/5	75.4	33.31 (10.34)	GINA criteria	Mild persistent asthma
Emtner 1998/Sweden/Yes	32/1	43.7	36 (10)	ATS criteria	Mild or moderate asthma
Pereira 2005/Brazil/Yes	40/0	77.5	33.4 (8.77)	Not stated	Moderate and severe persistent asthma

ATS = AmericanThoracic Society; GINA = Global Initiative for Asthma.