Table 1.
Characteristics of included studies.
| Author | Year | Country | N (OG/CG) | NOS |
|---|---|---|---|---|
| Murat | 2006 | Turkey | 30/30 | 8 |
| Ma Hm | 2007 | China | 34/57 | 7 |
| Yeşim | 2008 | Turkey | 34/15 | 8 |
| Wang et al. (young) | 2010 | China | 51/23 | 8 |
| Wang et al. (old) | 2010 | China | 32/29 | 8 |
| Leticia | 2013 | Brazil | 14/13 | 8 |
| Li et al. (mild) | 2014 | China | 41/33 | 7 |
| Li et al. (moderate) | 2014 | China | 40/33 | 7 |
| Li et al. (severe) | 2014 | China | 36/33 | 7 |
| Kumor et al. | 2006 | Poland | 32/12 | 8 |
| Ryan et al. (mild-moderate) | 2007 | Ireland | 35/30 | 8 |
| Ryan et al. (severe) | 2007 | Ireland | 31/30 | 8 |
| Basoglu et al. | 2011 | Turkey | 36/34 | 8 |
| Andaku et al. | 2015 | Brazil | 11/10 | 8 |
OG: OSA group; CG: control group; NOS: Newcastle-Ottawa Scale; N: sample size.