Characteristics of the obstructive sleep apnoea and control groups
| OSA patients | Control subjects | p-value | |
| Subjects n | 20 | 40 | |
| Age yrs | 51.0±11.8 | 48.4±9.9 | NS |
| BMI kg·m−2 | 29.7±6.0 | 23.6±2.9 | 0.0002 |
| ESS | 11.1±5.5 | 5.2±3.5 | 0.0002 |
| Beck scale | 6.9±5.1 | 5.9±6.5 | NS |
Data are expressed as mean±sd. OSA: obstructive sleep apnoea; BMI: body mass index; ESS: Epworth Sleepiness Scale; NS: nonsignificant.