TABLE 1.
Baseline characteristics of the total sample and subgroups of healthy population, fixed ratio only- and lower limit of normal (LLN)-defined airway obstruction
| Total sample | Healthy individuals# | Fixed ratio only | LLN | p-values | |||
| Healthy versus fixed ratio only | Healthy versus LLN | fixed ratio only versus LLN | |||||
| Subjects | 10 329 | 8 475 | 1278 | 576 | |||
| Males | 5849 (48) | 4067 (48) | 673 (53) | 265 (46) | 0.002 | 0.36 | 0.008 |
| Age years | 58.4±9.6 | 57.5±9.4 | 63.3±8.7 | 60.0±9.3 | <0.001 | <0.001 | <0.001 |
| BMI | |||||||
| Overall kg·m-2 | 26.6±4.4 | 26.7±4.4 | 26.3±4.2 | 25.4±4.5 | 0.0013 | <0.001 | <0.001 |
| Underweight | 85 (1) | 57 (1) | 9 (1) | 13 (2) | 0.91 | <0.001 | <0.001 |
| Normal weight | 4320 (38) | 3117 (37) | 514 (40) | 279 (49) | 0.023 | <0.001 | 0.001 |
| Overweight | 4868 (43) | 3674 (44) | 542 (43) | 196 (34) | 0.46 | <0.001 | <0.001 |
| Obese | 2097 (18) | 1576 (19) | 210 (16) | 86 (15) | 0.06 | 0.26 | 0.42 |
| Smoking | |||||||
| Current smokers |
2273 (20) | 1356 (16) | 389 (31) | 289 (50) | <0.001 | <0.001 | <0.001 |
|
Former smokers |
4262 (37) | 3134 (37) | 514 (40) | 194 (34) | 0.032 | 0.11 | 0.009 |
| Never-smokers | 4842 (43) | 3926 (47) | 369 (29) | 90 (16) | <0.001 | <0.001 | <0.001 |
| Pack-years | 19.2±18.0 | 16.9±16.3 | 24.5±19.7 | 30.3±21.5 | <0.001 | <0.001 | <0.001 |
Data are presented as n, n (%) or mean±sd, unless otherwise stated. BMI: body mass index. #: individuals who had completed spirometry without fixed ratio airway obstruction (FR-AO) nor LLN-AO. The percentages are for available data and not the total number. p-values <0.0015 are emphasised in bold, as they meet significance after Bonferroni correction for multiple comparisons.