Associations between clinical outcomes and airway obstruction defined by fixed ratio (FR) and lower limit of normal (LLN) and symptoms
| Healthy individuals | Model 1 | Model 2 | ||||||
| Airway obstruction | Airway obstruction | |||||||
| Fixed ratio | LLN | FR+/LLN− (n=1278) (ref.) versus FR+/LLN+ (n=576) | ||||||
| Ref. (%) versus LLN (%) | ||||||||
| Subjects n | 8475 | 1854 | 576 | |||||
| Shortness of breath | ||||||||
| At rest | 180 (2.1) | 1.00 | 66 (3.6) | 1.62 (1.19–2.19) | 31 (5.4) | 2.33 (1.56–3.48) | 2.8 versus 5.4 | 1.81 (1.11–2.94) |
| During daily activity# | 52 (0.6) | 1.00 | 33 (1.8) | 2.49 (1.58–3.93) | 17 (3.0) | 4.34 (2.41–7.81) | 1.3 versus 3.0 | 1.99 (0.98–4.1) |
| During exercise | 849 (10.1) | 1.00 | 359 (19.5) | 2.02 (1.75–2.32) | 176 (30.8) | 3.77 (3.09–4.60) | 14.5 versus 30.8 | 2.68 (2.09–3.43) |
| Chronic cough | 529 (6.3) | 1.00 | 285 (15.6) | 2.42 (2.06–2.84) | 144 (25.4) | 4.36 (3.50–5.41) | 11.2 versus 25.4 | 2.51 (1.93–3.26) |
| Chronic phlegm | 369 (4.4) | 1.00 | 211 (11.5) | 2.42 (2.01–2.91) | 114 (20.0) | 4.47 (3.53–5.67) | 7.7 versus 20.0 | 2.78 (2.06–3.75) |
| Chronic bronchitis¶ | 232 (2.8) | 1.00 | 146 (8.0) | 2.67 (2.14–3.33) | 85 (14.9) | 5.19 (3.95–6.83) | 4.8 versus 14.9 | 3.17 (2.22–4.53) |
| Nocturnal awakening | 589 (7.0) | 1.00 | 162 (8.7) | 1.21 (1.00–1.46)+ | 69 (12.0) | 1.70 (1.29–2.23) | 7.3 versus 12.0 | 1.65 (1.18–2.32) |
| Wheeze | 305 (3.6) | 1.00 | 215 (11.7) | 3.08 (2.53–3.73) | 115 (20.2) | 5.57 (4.34–7.14) | 7.9 versus 20.2 | 2.74 (2.03–3.70) |
Data are presented as n (%) and odds ratio (95% CI), unless otherwise stated. Multiple logistic regression analysis adjusted for age (as a dichotomous variable dividing the study sample at <60 years and ≥60 years, sex, ever-smoking and body mass index. #: cleaning and dressing; ¶: defined according to American Thoracic Society/European Respiratory Society guidelines; +: p-value=0.044.