| All subjects | Subjects without asthma | Subjects with asthma | p-value | |
| Subjects n | 523 | 268 | 255 | |
| Age years | 39.9±16.6 | 43.2±15.9 | 36.5±16.8 | <0.0001 |
| Sex female % | 51.0 | 57.5 | 44.3 | 0.003 |
| Body mass index kg·m−2 | 23.7±3.9 | 23.8±3.8 | 23.5±4.0 | 0.4 |
| Smoking habits % | ||||
| Never smokers | 51.6 | 49.6 | 53.7 | |
| Ex-smokers | 25.3 | 28.0 | 22.4 | 0.3 |
| Current smokers | 23.1 | 22.4 | 23.9 | |
| Asthma % | ||||
| Ever asthma | 48.7 | 100.0 | ||
| Current asthma | 40.5 | 83.1 | ||
| Age at asthma onset % | 237 | |||
| 0–4 years | 36.7 | |||
| 4–16 years | 39.7 | |||
| >16 years | 23.6 | |||
| Symptomatic score# | 1.17±1.35 (517) | 0.51±0.81 (266) | 1.86±1.46 (251) | <0.0001 |
| Asthma control (GINA 2006) % | ||||
| Controlled | 20.6 | 42.3 | ||
| Partly controlled | 10.7 | 22.0 | ||
| Uncontrolled | 8.2 | 16.9 | ||
| Eosinophilia (cells >5%) % | 12.4 | 6.7 | 18.4 | <0.0001 |
| Eosinophilic asthma (≥250 cells per mm2) % | 36.5 | |||
| FEV1 % pred | 103.4±17.2 | 108.5±16.6 | 98.0±17.5 | <0.0001 |
| Methacholine test¶ (PD20 ≤4 mg) % | 45.4 | 28.8 | 65.1 | <0.0001 |
| Inhaled corticosteroids past 12 months % | 20.6 | 2.2 | 40.0 | <0.0001 |
| Inhaled corticosteroids past 3 months % | 7.3 | 0.0 | 14.9 | |
| SPT+ and current rhinitis | ||||
| SPT+ % | 58.1 | 38.8 | 78.4 | <0.0001 |
| SPTQ (median number of SPT+) | 1 (0–3) | 0 (0–1) | 2 (1–4) | <0.0001 |
| Current rhinitis % | 39.2 | 22.3 | 56.9 | <0.0001 |
| SPT+ and current rhinitis % | 32.9 | 18.0 | 48.6 | <0.0001 |
| Biological phenotypes (geometric means) | ||||
| EBC NO2−/NO3− μmol per mg proteins | 2.25 (1.12–4.98) | 2.33 (1.15–4.81) | 2.16 (1.13–5.11) | 0.5 |
| FeNO ppb | 15.1 (10.0–23.0) | 13.2 (9.00–18.8) | 17.5 (11.5–29.6) | <0.0001 |
| EBC (NO2− + NO3−)/NO ratio (median) | 0.30 (0.04–0.60) | 0.34 (0.06–0.61) | 0.26 (0.04–0.58) | 0.16 |
| Plasma NO2−/NO3− μM | 39.1 (28.0–53.7) (510) | 38.9 (26.3–56.4) (263) | 39.3 (29.1–53.2) (247) | 0.8 |
| Eosinophil cells per mm3 | 170 (100–280) (505) | 145 (100–200) (256) | 199 (100–300) (249) | <0.0001 |
| IgE IU·mL−1 | 81.7 (28.8–226) | 49.8 (19.4–128) | 137 (59.0–332) | <0.0001 |
Data are presented as mean±sd, unless otherwise stated. Medians and geometric means are shown with interquartile ranges. Values of n are present in italics when differing from total n. GINA: Global Initiative for Asthma; FEV1: forced expiratory volume in 1 s; PD20: provocative dose causing a 20% fall in FEV1; SPT+: positive skin prick test, i.e. a mean wheal diameter ≥3 mm than the negative control for at least one of 12 aeroallergens; SPTQ: quantitative SPT score; EBC: exhaled breath condensate; FeNO: exhaled nitric oxide fraction; Ig: immunoglobulin. #: symptomatic score is based on the number of asthma symptoms (wheeze and breathlessness, woken with chest tightness, woken by attack of shortness of breath, attack of shortness of breath at rest, attack of shortness of breath after exercise); ¶: methacholine challenge test was not performed if baseline FEV1 <80% pred.