| Total | AHI quartile | p-value | ||||
| Q1 | Q2 | Q3 | Q4 | |||
| Subjects n | 11 911 | 2977 | 2965 | 2972 | 2997 | |
| Males | 8293 (69.6) | 1658 (55.7) | 1957 (66.0) | 2250 (75.7) | 2428 (81.0) | <0.0001 |
| Age years mean±sd | 52±12 | 47±13 | 52±12 | 54±12 | 53±12 | <0.0001 |
| Age ≥60 years | 3367 (28.3) | 532 (17.9) | 853 (28.8) | 1041 (35.0) | 941 (31.4) | <0.0001 |
| Smoking | ||||||
| Never | 8944 (75.6) | 2198 (74.1) | 2274 (77.2) | 2276 (77.0) | 2196 (74.0) | |
| Former/current | 2888 (24.4) | 768 (25.9) | 671 (22.8) | 679 (23.0) | 770 (26.0) | 0.0019 |
| Body weight | ||||||
| Normal | 1698 (14.3) | 770 (25.9) | 473 (16.0) | 321 (10.8) | 134 (4.5) | |
| Overweight | 4058 (34.2) | 1174 (39.5) | 1161 (39.3) | 1076 (36.3) | 647 (21.7) | |
| Obese | 6119 (51.5) | 1026 (34.5) | 1321 (44.7) | 1566 (52.9) | 2206 (73.9) | <0.0001 |
| BMI kg·m−2 | 31.3±6.7 | 28.8±5.8 | 30.2±6.0 | 31.3±6.1 | 34.9±7.3 | <0.0001 |
| Neck circumference cm | 41.1±4.7 | 38.7±4.4 | 40.3±4.2 | 41.5±4.1 | 43.7±4.5 | <0.0001 |
| Waist/hip ratio | 0.97±0.09 | 0.93±0.09 | 0.96±0.08 | 0.98±0.08 | 1.00±0.08 | <0.0001 |
| ESS score | 9.7±5.3 | 9.0±5.2 | 9.3±5.0 | 9.7±5.0 | 11.0±5.5 | <0.0001 |
| Systemic hypertension | 4930 (41.4) | 714 (24.0) | 1154 (38.9) | 1398 (47.0) | 1664 (55.6) | <0.0001 |
| Type 2 diabetes | 1154 (9.7) | 144 (4.8) | 239 (8.1) | 325 (10.9) | 446 (14.9) | <0.0001 |
| Dyslipidaemia | 2481 (20.8) | 398 (13.4) | 581 (19.6) | 720 (24.2) | 782 (26.1) | <0.0001 |
| COPD | 590 (5.0) | 137 (4.6) | 134 (4.5) | 138 (4.6) | 181 (6.0) | 0.0181 |
| Mean SpO2 % | 93.4±3.2 | 94.8±1.9 | 94.1±2.4 | 93.5±2.3 | 91.0±4.4 | <0.0001 |
| Lowest SpO2 % | 80.7±10.9 | 87.7±5.8 | 83.8±7.5 | 80.6±8.0 | 71.1±12.9 | <0.0001 |
| Systolic blood pressure mmHg | 134±18 | 130±18 | 133±18 | 134±18 | 137±18 | <0.0001 |
| Diastolic blood pressure mmHg | 82±12 | 81±11 | 82±11 | 83±12 | 84±12 | <0.0001 |
Data are presented as n (%) unless otherwise stated. Normal weight defined as having a body mass index (BMI) between 18 and 24.9 kg·m-2; overweight, between 25 and 29.9 kg·m-2; and obese, more than 30 kg·m−2. p-values are for overall F-test or χ2-test. ESS: Epworth Sleepiness Scale; COPD: chronic obstructive pulmonary disease; SpO2: arterial oxygen saturation measured by pulse oximetry.