Odds ratios (or) for being employed at followup
| Variable | OR | 95% CI |
| Age yrs*** | 0.91 | 0.87–0.95 |
| Level of education# | ||
| ≤9 yrs, 10–12 yrs, >12 yrs | 2.21 | 1.25–3.89 |
| SIC result | ||
| positive versus negative | 0.62 | 0.27–1.45 |
| Asthmaseverity score 28point scale | 0.91 | 0.78–1.06 |
| Log PC20 Loge unit | 0.91 | 0.75–1.12 |
| Time elapsed since onset of workrelated symptoms months | 0.99 | 0.99–1.02 |
| Company size | ||
| number of workers ≤10, 10–100, >100 | 0.98 | 0.60–1.62 |
CI: confidence interval
SIC: specific inhalation challenge
PC20: provocation concentration causing a 20% fall in forced expiratory volume in one second
***: p<0.001
#: p=0.006