Table 1: Characteristics of included studies.

AuthorYearCountry (OG/CG)NOS

Murat2006Turkey30/308
Ma Hm2007China34/577
Yeşim2008Turkey34/158
Wang et al. (young)2010China51/238
Wang et al. (old)2010China32/298
Leticia2013Brazil14/138
Li et al. (mild)2014China41/337
Li et al. (moderate)2014China40/337
Li et al. (severe)2014China36/337
Kumor et al.2006Poland32/128
Ryan et al. (mild-moderate)2007Ireland35/308
Ryan et al. (severe)2007Ireland31/308
Basoglu et al.2011Turkey36/348
Andaku et al.2015Brazil11/108

OG: OSA group; CG: control group; NOS: Newcastle-Ottawa Scale; : sample size.