TABLE 2

Associations between clinical outcomes and airway obstruction defined by fixed ratio (FR) and lower limit of normal (LLN) and symptoms

Healthy individualsModel 1Model 2
Airway obstructionAirway obstruction
Fixed ratioLLNFR+/LLN (n=1278) (ref.)
versus
FR+/LLN+ (n=576)
Ref. (%) versus LLN (%)
Subjects n84751854576
Shortness of breath
 At rest180 (2.1)1.0066 (3.6)1.62 (1.19–2.19)31 (5.4)2.33 (1.56–3.48)2.8 versus 5.41.81 (1.11–2.94)
 During daily activity#52 (0.6)1.0033 (1.8)2.49 (1.58–3.93)17 (3.0)4.34 (2.41–7.81)1.3 versus 3.01.99 (0.98–4.1)
 During exercise849 (10.1)1.00359 (19.5)2.02 (1.75–2.32)176 (30.8)3.77 (3.09–4.60)14.5 versus 30.82.68 (2.09–3.43)
Chronic cough529 (6.3)1.00285 (15.6)2.42 (2.06–2.84)144 (25.4)4.36 (3.50–5.41)11.2 versus 25.42.51 (1.93–3.26)
Chronic phlegm369 (4.4)1.00211 (11.5)2.42 (2.01–2.91)114 (20.0)4.47 (3.53–5.67)7.7 versus 20.02.78 (2.06–3.75)
Chronic bronchitis232 (2.8)1.00146 (8.0)2.67 (2.14–3.33)85 (14.9)5.19 (3.95–6.83)4.8 versus 14.93.17 (2.22–4.53)
Nocturnal awakening589 (7.0)1.00162 (8.7)1.21 (1.00–1.46)+69 (12.0)1.70 (1.29–2.23)7.3 versus 12.01.65 (1.18–2.32)
Wheeze305 (3.6)1.00215 (11.7)3.08 (2.53–3.73)115 (20.2)5.57 (4.34–7.14)7.9 versus 20.22.74 (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.