Subject characteristics
| Control subjects | Athletes | P value | Sport disciplines | ||||
| Basketball players | Football players | Volleyball players | Swimmers | ||||
| No (n=) | 25 | 90 | 24 | 38 | 14 | 14 | |
| Age (years) | 15.59±1.64 | 15.53±1.41 | 0.9225 | 15.88±1.30 | 15.39±1.22 | 16.64±1.08 | 14.21±1.31 |
| Gender (M/F) | 13/12 | 51/39 | 0.8204 | 20/4 | 18/20 | 4/10 | 9/5 |
| BMI | 19.84±3.00 | 20.79±3.06 | 0.1677 | 22.35±2.53** | 19.53±3.56 | 21.35±1.65 | 21.00±2.10 |
| Atopy (n=) | 9 (36%) | 42 (47%) | 0.3423 | 10 (42%) | 14 (37%) | 7 (50%) | 2 (14%) |
| FEV1 (L) | 3.83±0.77 | 4.11±0.88 | 0.1391 | 4.78±0.86** | 3.57±0.66 | 4.29±0.50 | 4.25±0.89 |
| FEV1% predicted | 104.4±9.5 | 108.0±12.4 | 0.1890 | 104.6±10.3 | 105.0±11.8 | 107.6±11.7 | 121.1±10.7*** |
| FVC (L) | 4.35±0.89 | 4.81±1.09 | 0.0569 | 5.58±1.08** | 4.12±0.81 | 5.00±0.50 | 5.17±1.24 |
| FVC% predicted | 103.5±10.0 | 109.6±14.1 | 0.0447 | 105.1±12.5 | 106.1±11.9 | 109.7±11.1 | 126.6±13.0**** |
| FeNO (ppb) | 10.0 (7.5–14.5) | 14.0 (10.0–23.0) | 0.0114 | 18.5 (13.3–39.0)* | 12.5 (9.0–22.3) | 13.0 (10.0–18.0) | 13.5 (9.8–22.5) |
| Achieved target ventilation (%) | 97.2±15.6 | 94.7±16.3 | 0.4924 | 95.9±18.8 | 94.3±13.8 | 94.0±17.8 | 92.4±12.6 |
| Training years | / | 10 (9–11) | / | 10 (9–11) | 10 (9–12) | 10 (7–11) | 10 (9–11) |
| Hours of sports a week | 4 (3–5) | 20 (16–22) | <0.0001 | 20 (18–22)**** | 18 (15–20)**** | 20 (20–22)**** | 21 (16–22)**** |
| Smoking state (yes/no) | 3/22 | 1/89 | 0.0318 | 0/24 | 1/37 | 0/14 | 0/14 |
| Sputum total cell count (×106) | 0.4 (0.3–0.9) | 1.0 (0.5–1.8) | 0.0341 | 1.2 (0.5–4.7) | 0.9 (0.4–1.5) | 0.9 (0.6–2.0) | NA |
| Sputum macrophages (%) | 98.0 (92.3–98.8) | 96.4 (89.2–99.1) | 0.4288 | 94.0 (59.0–100.0) | 97.7 (91.4–99.25) | 94.1 (93.6–98.3) | NA |
| Sputum neutrophils (%) | 1.0 (0–5.6) | 1.2 (0–9.8) | 0.9382 | 1.0 (0–40.0) | 1.2 (0–−6.6) | 2.8 (0–6.2) | NA |
| Sputum eosinophils (%) | 0 (0–0) | 0 (0–0) | 0.8758 | 0 (0–0) | 0 (0–0) | 0 (0–0) | NA |
| Sputum lymphocytes (%) | 0.8 (0.3–1.2) | 0.6 (0–2.0) | 0.9068 | 0 (0–1.7) | 1.3 (0.4–2.5) | 0.6 (0–1.4) | NA |
P value represents the p value obtained with statistical analysis among controls and whole athletes’ group. Normally distributed data are represented as mean±SD and analysed viat-test. Non-parametric data are represented as median with IQR and analysed with Mann-Whitney U test.
*p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 compared with control subjects (one-way ANOVA for parametric data and Kruskall-Wallis test for non-parametric data).
ANOVA, analysis of variance; BMI, body mass index; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; NA, not available.