Table 1.
Clinical characteristics of asthmatic adolescents with or without bronchial hyperresponsiveness
| Characteristic | BHR (+) (n=113) | BHR (-) (n=102) | P value |
|---|---|---|---|
| Age (yr) | 14±2.4 | 14±2.0 | 1.000 |
| Male sex | 78 (69) | 71 (70) | 0.956 |
| Age at the 1st wheeze started (yr) | |||
| <3 | 42 (37) | 43 (42) | 0.465 |
| ≥3, <6 | 14 (12) | 17 (17) | 0.398 |
| ≥6 | 57 (51) | 42 (41) | 0.248 |
| Admission with LRI during 1st 3 years of life | 37 (33) | 38 (37) | 0.567 |
| Combined allergic disease | |||
| Allergic rhinitis | 81 (72) | 75 (74) | 0.762 |
| Atopic dermatitis | 55 (49) | 38 (37) | 0.092 |
| Parental allergic disease | 45 (40) | 36 (35) | 0.494 |
| Atopic sensitization | 106 (94) | 90 (88) | 0.228 |
| House dust mite | 97 (92) | 77 (86) | 0.054 |
| Tree pollen | 47 (44) | 51 (57) | 0.221 |
| Grass pollen | 25 (24) | 26 (29) | 0.347 |
| Weed pollen | 37 (35) | 38 (42) | 0.567 |
| Mold | 34 (32) | 19 (21) | 0.050 |
| Pet | 39 (37) | 19 (21) | 0.009 |
| Food | 14 (13) | 17 (19) | 0.448 |
| Polysensitization | 68 (64) | 66 (73) | 0.526 |
| Total serum IgE (IU/mL), median (IQR) | 462 (208.9–1,044) | 329 (138.3–664.5) | 0.102 |
| Eosinophil (count/mm3), median (IQR) | 561 (279–778) | 400 (208–602) | 0.007 |
| Body mass index (kg/m2) | 21.7±4.1 | 21.9±6.7 | 1.002 |
| Asthma severity, median (range) | 2 (1–4) | 1 (1–4) | 0.001 |
| Pulmonary function test | - | 96±13.7 | |
| FEV1 (%predicted) | 91±14.4 | 94±15.9 | 0.013 |
| FVC (%predicted) | 94±13.7 | 86±8.0 | 1.000 |
| FEV1/FVC (%) | 84±10.5 | 58 (57) | 0.042 |
| <90 | 87 (77) | 44 (43) | 0.002 |
| ≥90 | 26 (23) | NA | - |
| Methacholine PC20 (mg/mL), median (IQR) | 5 (1.4–16) | - | - |
| <1 | 25 (22) | - | - |
| 1–4 | 24 (21) | - | - |
| >4 | 64 (57) | - | - |
| Current asthma | 75 (66) | 32 (31) | 0.000 |
| PC20, <1 | 19/25 (76) | - | 0.001a) |
| PC20, 1–4 | 19/24 (79) | - | - |
| PC20, >4 | 37/64 (58) | - | - |
Values are presented as mean±standard deviation or number (%) unless otherwise indicated.
BHR, bronchial hyperresponsiveness; LRI, lower respiratory infection; IQR, interquartile range; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; PC20, provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second; NA, not available.
Comparison of current asthma frequency among the 3 BHR groups. Asthma severity: 1, mild-intermittent; 2, mild-persistent; 3, moderate-persistent; 4, severe-persistent. Current asthma: episodes of wheeze verified by physicians or asthma exacerbation in the previous year.
Boldface indicates a statistically significant difference with P<0.05.