Table 4– Lung function, smoking, and risks for PD15 ≤1.6 mg and PD15 ≤0.4 mg, analysed by univariate and multivariate analysis
Independent variablesSubjectsDependent variables
PD15 ≤1.6 mgPD15 ≤0.4 mg
BHROR (95% CI)BHROR (95% CI)
Univariate analysis292
 Lung function
  FEV1 <80% pred38194.91 (2.40–10.04)1010.98 (4.01–30.11)
  FEV1/FVC <0.723113.92 (1.64–9.38)813.81 (4.76–40.09)
  MEF50 <63% pred77376.99 (3.79–12.89)1517.02 (4.77–60.68)
  FEV1<80% pred and FEV1/FVC <0.71275.73 (1.75–18.73)734.24 (9.36–125.17)
  FEV1<80% pred and MEF50 <63% pred24157.80 (3.22–18.89)1023.13 (7.90–67.69)
 Current smokers and lung function96
  Smokers with FEV1 <80% pred221510.17 (3.93–26.31)814.86 (5.08–43.49)
  Smokers with FEV1/FVC <0.71288.37 (2.43–28.82)734.24 (9.36–125.17)
  Smokers with MEF50 <63% pred37216.85 (3.30–14.23)1011.44 (4.16–31.43)
Multivariate analysis292
 Age ≥45 years0.56 (0.27–1.14)0.52 (0.14–2.00)
 Lung function
  FEV1 <80% pred2.69 (1.06–6.84)5.78 (1.55–21.54)
  MEF50 <63% pred5.53 (2.70–11.32)8.34 (1.82–38.18)
 Female#2.12 (1.04–4.34)0.93 (0.26–3.34)
 Wheezing or asthma in childhood3.99 (1.24–12.85)1.05 (0.09–11.74)
 Smoking pack-years
  Nonsmokers11
  0–50.45 (0.14–1.50)+
  5–151.30 (0.53–3.22)1.40 (0.23–8.61)
  >153.00 (1.33–6.76)5.80 (1.27–26.62)
Multivariate analysis292
 Age ≥45 years0.61 (0.31–1.21)0.67 (0.20–2.31)
 Lung function
  MEF50 <63% pred7.64 (3.92–14.88)19.04 (4.77–75.97)
 Female#1.92 (0.97–3.80)0.69 (0.22–2.14)
 Wheezing or asthma in childhood4.15 (1.35–12.76)1.77 (0.17–18.13)
 Smoking pack-years
  Nonsmokers11
  <8.50.64 (0.24–1.68)0.45 (0.04–4.79)
  ≥8.52.58 (1.26–5.31)5.00 (1.25–19.92)
  • Data are presented as n, unless otherwise stated. PD15: provocative dose of histamine inducing a 15% fall in forced expiratory volume in 1 s (FEV1); BHR: bronchial hyperresponsiveness; % pred: % predicted; FVC: forced vital capacity; MEF50: maximal expiratory flow at 50% of FVC [21]. #: males as reference group; : “no” as reference group; +: n = 0.