Characteristics of participants in relation to body mass index (BMI)
| BMI <20 | BMI ≥20–<25 | BMI ≥25–<30 | BMI ≥30 | All | p-value | |
| Subjects n | 1222 | 8158 | 5201 | 1393 | 15974 | |
| Females | 83.8 | 57.9 | 38.1 | 51.3 | 52.8 | <0.0001 |
| Age yrs | 37±7.1 | 39±7.2 | 40±7.2 | 41±6.9 | 39±7.1 | <0.0001 |
| Nocturnal GOR >1·week−1 | 4.4 | 5.1 | 10.2 | 15.8 | 8.9 | <0.0001 |
| Snoring >3·week−1 | 6.7 | 11.9 | 25.7 | 38.6 | 20.7 | <0.0001 |
| Onset of asthma | 3.6 | 3.4 | 4.2 | 5.9 | 3.9 | 0.0003 |
| Onset of wheeze | 10.2 | 10.1 | 12.7 | 21.7 | 11.8 | <0.0001 |
| Onset of night-time symptoms | 8.2 | 8.5 | 8.9 | 14.1 | 9.1 | <0.0001 |
Data are presented as mean±sd or per cent, unless otherwise stated
GOR: gastro-oesophageal reflux