Characteristics of the study population
| Group | ||
| Sy−/Se− (n=71) | Sy+/Se− (n=29) | |
| Age (years)* | 29.0 (16–46) | 31.0 (22–58) |
| Sex (women)† | 51 (71.8) | 18 (62.1) |
| Education level | ||
| High | 55 (77.5) | 20 (69.0) |
| Middle | 15 (21.1) | 8 (–) |
| Low | 1 (–) | 1 (–) |
| Nationality | ||
| Switzerland | 28 (39.4) | 12 (41.4) |
| Germany | 14 (19.7) | 11 (37.9) |
| Italy | 10 (14.1) | 1 (–) |
| Other | 19 (26.8) | 5 (–) |
| Smoking | ||
| Never | 50 (70.4) | 23 (79.3) |
| Former | 8 (–) | 4 (–) |
| Current | 13 (18.3) | 2 (–) |
| Pack-years (Cigarette smokers only) (n) | 2.10 (0.05–14) (n=21) | 0.25–15.0 (n=6) |
| BMI (kg/m2) | 22.3 (17.3–36.0) | 23.3 (16.4–35.4) |
| FEV1 (per cent predicted)‡ | 103.1 (80.3–128.5) | 103.1 (68.9–136.9) |
| FEV1/FVC (%)‡ | 79.3 (63.7–94.9) | 78.0 (58.2–90.1) |
| Health condition | ||
| ‘Symptomatic’§ | ||
| No | 23 (32.4) | 0 (–) |
| Non-WR | 48 (67.6) | 0 (–) |
| WR | 0 (–) | 29 (100) |
| Allergic rhinitis | ||
| No | 49 (69.0) | 11 (37.9) |
| Non-WR | 22 (31.0) | 8 (–) |
| WR | 0 (0) | 10 (34.5) |
| Any allergic disease | ||
| No | 36 (50.7) | 3 (–) |
| Non-WR | 35 (49.3) | 2 (–) |
| WR | 0 (0) | 24 (82.8) |
| Asthma‡ | ||
| No | 57 (80.3) | 21 (72.4) |
| Non-WR | 14 (19.7) | 4 (–) |
| WR | 0 (–) | 4 (–) |
| Total IgE (kU/L) | 28.1 (1.00–1104) | 63.3 (1.00–1127) |
| Total IgE | ||
| ≤100 | 58 (81.7) | 19 (65.5) |
| >100 | 13 (18.3) | 10 (34.5) |
| Lifelong occupational exposure to animals (years) | 3.0 (0–9) | 7.0 (0–37) |
| Exposure in last job (years) | 2.0 (0–9) | 2 (0–19) |
*Median and range (one case without group assignment is missing).
†Number and per cent (one case without subgroup assignment is missing).
‡Results include only acceptable spirometric curves in Caucasians. For FEV1 (FEV1/FVC), subgroup size is 56 (53) and 28 (28) in Sy−/Se− and Sy+/Se−, respectively.
§Definition of ‘symptomatic’, see the Methods section. According to the classification scheme, subjects having any predefined symptom are considered asymptomatic when the symptom is not WR.
BMI, body mass index; FEV1/FVC, forced expiratory volume in 1 s/forced vital capacity; IgE, immunoglobulin E; WR, work related.