| All patients | Males | Females | |
| Subjects n | 529 | 424 | 105 |
| Age yrs | 51.3±12.8 | 50.9±13.0 | 52.9±12.0 |
| Hypertension | 35.2 | 36.6 | 29.5 |
| Dyslipidaemia | 32.5 | 35 | 30.0 |
| Diabetes mellitus | 17.0 | 16.5 | 19 |
| BMI kg·m−2 | 30.8±6.0 | 30.6±5.4 | 31.6±7.9 |
| Obesity# | 49 | 48.3 | 51.4 |
| Neck circumference cm | 41.6±4.1 | 42.7±3.5 | 37.3±3.8*** |
| AHI events·h−1 | 43.4±27.6 | 44.8±26.7 | 37.7±30.7+ |
| ArI events·h−1 | 51.5±23.2 | 52.4±22.6 | 47.8±25.3 |
| Mean nocturnal Sa,O2 % | 92.3±4.0 | 92.1±4.0 | 93.0±4.0 |
| Lowest Sa,O2 % | 80.8±9.3 | 80.5±9.3 | 81.6±9.4 |
| ESS score | 9.7±5.1 | 9.8±5.0 | 9.5±5.5 |
| Daytime sleepiness¶ | 51.8 | 51.4 | 53.3 |
| Diagnosis of metabolic syndrome | 51.2 | 51.4 | 50.5 |
| High blood pressure | 54.6 | 55.4 | 51.4 |
| High waist circumference | 72 | 70.8 | 77.1 |
| Low HDL cholesterol | 26.8 | 26.7 | 27.6 |
| High triglyceride level | 45.9 | 47.6 | 39 |
| High fasting blood glucose | 49.9 | 50.7 | 46.7 |
Data are presented as mean±sd or %, unless otherwise stated. BMI: body mass index; AHI: apnoea/hypopnoea index; ArI: arousal index; Sa,O2: arterial oxygen saturation; ESS: Epworth Sleepiness Scale; HDL: high-density lipoprotein. #: BMI ≥30 kg·m−2; ¶: ESS ≥10. ***: p<0.001; +: p=0.02 for difference between sexes by unpaired t-test or Chi-squared analysis.