Table 1 Characteristics of adults with asthma included in the analyses
Parametern (SD)
All, n381
    Cases with asthma, n200
    Relatives with asthma, n181
Age, year, mean (SD)36.5 (13.1)
Sex, women, %49.6
Age of asthma onset, year, mean (SD)18.0 (14.7)
Total IgE, IU/ml, GM166
Skin prick test positive response (any of 11 allergens), %75.1
White blood cell counts
    Eosinophils/mm3, mean (SD)275 (200)
    Neutrophils/mm3, mean (SD)4202 (1667)
FEV1 % predicted, mean (SD)93.5 (19.9)
FEV1 <80% predicted, %21.4
Methacholine challenge, n*185
    PD20⩽4 mg, %75.1
Current asthma (asthma attacks in the last 12 months), %72.3
Nocturnal symptoms (last 12 months), %
    Cough46.5
    Chest tightness66.0
    Shortness of breath46.3
Asthma events score, last 12 months (1–4)142.36 (1.21)
Asthma symptomatic score, last 12 months (1–5)152.96 (1.77)
COPD-like symptoms, %
    Chronic cough19.7
    Chronic phlegm14.8
    Dyspnoea grade 322.4
Smoking habits, %
    Smokers21.7
    Ex-smokers26.8
    Non-smokers51.5
Body mass index, kg/m2, mean (SD)23.3 (16.2)
Respiratory infection (last 3 weeks), %14.7
Treatment (last 12 months), %
    None27.3
    Without inhaled steroids20.5
    With inhaled steroids52.2

  • *Not performed if FEV1 <80% predicted.

  • COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; GM, geometric mean; IgE, immunoglobulin E; PD20, dose of methacholine causing a 20% drop in FEV1.