| Age years mean±sd | 11.4±0.3 |
| Males | 1286 (50.9) |
| Asthma symptoms | 317 (12.6) |
| Frequent asthma symptoms | 97 (3.9) |
| Infrequent asthma symptoms | 220 (8.7) |
| Diagnosed asthma (including asthma during the previous 12 months) | 100 (4.0) |
| No asthma symptoms | 2202 (87.4) |
| Specific aspects of asthma | |
| Wheezing during the last year | 116 (4.6) |
| Dyspnoea during the last year | 243 (9.6) |
| Corticosteroids | 169 (6.7) |
| Ever-diagnosed with asthma | 288 (11.4) |
| Sleep mean (sd min) | |
| Bedtime school day | 20:43 h (27.4) |
| Bedtime not school day | 21:41 h (39.7) |
| Time in bed school day | 10:06 h (39.2) |
| Time in bed nonschool day | 11:23 h (55.0) |
| Sleep latency | |
| Fall asleep immediately | 619 (24.5) |
| Stay awake for a while | 1509 (59.8) |
| Takes a long time to fall asleep | 394 (15.6) |
| Nocturnal awakenings | |
| (Almost) never | 1324 (52.5) |
| Sometimes | 1090 (43.2) |
| (Almost) every night | 110 (4.4) |
| Sleep latency after nocturnal awakenings | |
| Mostly fall asleep immediately | 615 (51.3) |
| Mostly awake for a while | 488 (40.7) |
| Mostly takes a long time to fall asleep | 96 (8.0) |
| Feeling fit at rise time school day | |
| Yes | 2061 (82.0) |
| No | 452 (18.0) |
| Daytime sleepiness/tiredness | |
| (Almost) never | 1069 (42.4) |
| <1 per week | 880 (34.9) |
| ±1 per week | 282 (11.2) |
| ±2 per week | 165 (6.5) |
| ≥3 per week | 124 (4.9) |
Data are presented as n (%), unless otherwise stated. #: n=2529.