Table 1. Characteristics of included studies in the meta-analysis.
| Author (year) | Country | Ethnicity | Genotyping | OSAHS subjects | Control subjects | pHWE | ||||||
| Age | BMI | Gender(M/F) | AHI(events/h) | Age(year) | BMI(Kg/m2) | Gender(M/F) | AHI(events/h) | |||||
| Almpanidou(2012) | Greek | Caucasian | DNA sequencing | 51.0±12.4 | 31.4±5.24 | 198/22 | 42.6±27.5 | 50.6±13.8 | 29.6±4.3 | 278/41 | 3.3±2.2 | 0.11 |
| Bhushan(2009) | India | Asian | PCR-RFLP | 46±18 | 31.5±4 | 84/20 | 48±25 | 44±10 | 31±4 | 65/38 | 2.8±1.7 | <0.01 |
| Guan (2013) | China | Asian | PCR-RFLP | 43.6±11.7 | 27.4±3.4 | 452/79 | 49.9±26.8 | 42.6±13.1 | 26.89±3.7 | 126/36 | <5 | 0.60 |
| Li(2013) | China | Asian | DNA sequencing | 45.0±9.0 | 29.4±2.1 | 155/0 | 57.5±16.3 | 46.3±8.0 | 24.1±2.3 | 100/0 | <5 | 0.52 |
| Liu(2006) | China | Asian | PCR-RFLP | 44.3±9.8 | 26.3±3.5 | 67/9 | ≥5 | 41.7±10.1 | 25.7±3.3 | 37/5 | <5 | 0.07 |
| Popko(2008) | Poland | Caucasian | PCR-RFLP | 21∼27 | >25 | 74/28 | ≥5 | 18∼65 | NR | 39/38 | <5 | 0.25 |
| Riha(2005) | UK | Caucasian | TaqMan | 52±9 | 30±6 | 83/20 | ≥15 | 51±10 | 27±5 | 33/30 | NR | 0.34 |
Abbreviation: OSAHS, obstructive sleep apnea-hypopnea syndrome; NR, not reported; BMI, body mass index; AHI, apnea-hypopnea index; HWE, Hardy–Weinberg equilibrium; PCR: polymerase chain reaction; PCR-RFLP: PCR-restriction fragment length polymorphism.