Table 2.

General information of the literature was included (cross-sectional study).

Author	Population origin	Diagnostic mode	Sample size	Children age (y)	Active or passive smoking
Villarreal 2003[14]∗	North America	ISAAC	6749	6–8,11–14	active
Obihara 2005[24]	Africa	questionnaire	884	6–14	active
Horak 2007[20]	Europe	ISAAC	4109	preschool child	active
Lee 2012–1[16]	Asia	ISAAC	7393	≤14	active
Lee 2012–2[16]	Asia	ISAAC	7393	≤14	passive
Chen 2012–1[15]	Asia	questionnaire	4221	6–9,10–12, 13–15	active
Chen 2012–2[15]	Asia	questionnaire	4221	6–9,10–12, 13–15	passive
Azalim 2014[25]†	South America	ISAAC	1302	child: 6–7, teenager: 13–14	active
Huang 2019[11]	Asia	questionnaire	2214	3–6	active
Li 2019[26]	Asia	questionnaire	3606	3–6	passive

^∗Rhinitis without flu or cold and rhinitis plus ocular symptoms.

^†Rhinitis and rhinitis asthma complications.

ISAAC = international study of asthma and allergies in childhood (ISAAC), SPT = skin prick test.