Table 1.
Characteristics of the asthmatic individuals and unadjusted associations of baseline determinants (OR) with persistent asthma and COPD at follow up.
| Diagnosis at follow up |
|||||
|---|---|---|---|---|---|
| Asthma at baseline (n = 239) |
Persistent asthma (n = 164) |
COPD (n = 35) |
|||
| Determinants, baseline | n (%) | n (%) | OR (95%CI) | n (%) | OR (95%CI) |
| Sex, female | 150 (62.8%) | 99 (60.4%) | 0.72 (0.38–1.32) | 22 (62.9%) | 1.00 (0.45–2.31) |
| Age ≥35 years | 122 (51.1%) | 80 (48.8%) | 0.75 (0.42–1.34) | 22 (62.9%) | 1.76 (0.80–4.01) |
| Age of onset ≥16 yearsa | 119 (55.6%) | 81 (52.3%) | 0.60 (0.31–1.17) | 15 (48.4%) | 0.71 (0.31–1.64) |
| Bronchial hyperresponsivenessb | 95 (39.8%) | 65 (39.6%) | 1.11 (0.60–2.07) | 14 (40.0%) | 1.81 (0.71–4.81) |
| Atopy | 146 (61.1%) | 104 (63.4%) | 1.36 (0.75–2.46) | 17 (48.6%) | 0.55 (0.25–1.21) |
| FEV₁ below pred | 191 (79.9%) | 139 (84.8%) | 2.46(1.21–4.95) | 33 (94.3%) | 4.80(1.15–42.65) |
| ACOS | 46 (19.3%) | 39 (23.8%) | 3.03(1.25–8.43) | 19 (54.3%) | 7.78(3.31–18.23) |
| Medication, 12 mth | |||||
| SABA only | 63 (26.4%) | 48 (29.3%) | 5.06(2.43–10.54) | 8 (22.9%) | 1.15 (0.42–3.17) |
| ICS and/or LABA | 96 (40.2%) | 85 (51.8%) | 12.21(5.64–26.45) | 18 (51.4%) | 1.82 (0.77–4.31) |
| Asthma Scorec | 1.48(1.20–1.82) | 1.16 (0.91–1.48) | |||
| BMI >30 kggm−2d | 46 (19.3%) | 31 (19.0%) | 0.94 (0.45–2.02) | 5 (14.3%) | 0.66 (0.19–1.87) |
| Nasal allergy | 168 (70.3%) | 122 (74.4%) | 1.83 (0.98–3.41) | 22 (62.9%) | 0.67 (0.30–1.56) |
| Parental asthma | 92 (38.5%) | 67 (40.9%) | 1.38 (0.75–2.57) | 13 (37.1%) | 0.93 (0.41–2.07) |
| Current smoking | 68 (28.5%) | 37 (22.6%) | 0.41(0.22–0.78) | 14 (40.0%) | 1.85 (0.81–4.13) |
| High-risk occupation (asthma)e | 119 (50.4%) | 81 (50.0%) | 0.95 (0.53–1.70) | 15 (42.9%) | 0.70 (0.31–1.53) |
| High-risk occupation (COPD)f | 126 (53.4%) | 85 (52.5%) | 0.89 (0.49–1.60) | 16 (45.7%) | 0.70 (0.32–1.52) |
| White collar workg | 153 (64.6%) | 103 (63.2%) | 0.70 (0.32–1.47) | 22 (62.9%) | 0.76 (0.31–1.93) |
| Blue collar workg | 55 (23.2%) | 41 (25.2%) | 1.42 (0.68–3.09) | 10 (28.6%) | 1.32 (0.52–3.18) |
| Respiratory infection <5 years of age | 30 (12.6%) | 23 (14.0%) | 1.58 (0.62–4.58) | 8 (22.9%) | 2.45 (0.85–6.43) |
| Mould inside the home | 85 (35.6%) | 57 (34.8%) | 0.89 (0.49–1.65) | 15 (42.9%) | 1.44 (0.64–3.15) |
Bold values denote significant associations (p < 0.05).
an = 214; 25 participants missing in variable ‘age at onset’.
bn = 210; 29 missing i.e. did not receive methacholine challenge test
cAsthma score as a continuous variable.
dn = 238; 1 participant missing in variable BMI.
en = 236; 3 participants missing in variable ‘high-risk occupation (asthma)’.
fn = 236; 3 participants missing in variable ‘high-risk occupation (COPD)’.
gn = 208; 2 participants missing, 29 unclassifiable.
The table shows odds ratios (OR) with 95% confidence intervals (95% CI).