Table 1. Characteristics of patients with asthma, according to age group.* .
| Characteristics | Young Adult Asthma (n = 761) | Older Asthma (n = 369) | p value† | |
|---|---|---|---|---|
| Age—yr | 30.5 ± 7.7 | 54.0 ± 7.0 | <0.0001 | |
| Sex—no (%) | 0.34 | |||
| Male | 267 (35) | 120 (32.5) | ||
| Female | 494 (65) | 249 (67.5) | ||
| Race—no (%) | <0.0001 | |||
| White | 466 (61) | 274 (74) | ||
| Black | 230 (30) | 78 (21) | ||
| Asian | 15 (2) | 7 (2) | ||
| Others | 50 (7) | 10 (3) | ||
| BMI | 29.4 ± 8.3 | 31.0 ± 7.4 | 0.002 | |
| Previous history of pneumonia—no (%) | 309 (41) | 203 (55) | 0.0003 | |
| History of recurrent bronchitis—no (%) | 243 (32) | 176 (48) | <0.0001 | |
| History of sinusitis—no (%) | 280 (37) | 197 (53) | <0.0001 | |
| History of sinus surgery—no (%) | 84 (11) | 82 (22) | <0.0001 | |
| Nasal polyps—no (%) | 74 (10) | 62 (17) | <0.0001 | |
| History of nasal polyps removal—no (%) | 53 (7) | 62 (17) | <0.0001 | |
| GERD—no (%) | 165 (22) | 154 (42) | <0.0001 | |
| History of allergies—no (%) | 704 (93) | 318 (86) | 0.001 | |
| Positive skin reactivity—no (%) | 667 (88) | 282 (76) | <0.0001 | |
| Symptoms caused by pets—no (%) | 549 (72) | 208 (56) | <0.0001 | |
| Symptoms caused by physical activity—no (%) | 480 (63) | 282 (76) | <0.0001 | |
| Number of positive skin reactions. | 4.36 (2.80) | 3.22 (2.66) | <0.0001 | |
| FEV1 | ||||
| Value—liters | 3.65 ± 1.52 | 2.25 ± 0.73 | 0.0009 | |
| Percent of predicted value | 92.11 ± 17.68 | 76.04 ± 20.08 | <0.0001 | |
| FVC | ||||
| Value—liters | 4.2 ± 1.1 | 3.2 ± 0.9 | <0.0001 | |
| Percent of predicted value | 99.4 ± 14.9 | 86.3 ± 16.5 | <0.0001 | |
| FEV1/FVC ratio | 0.72 ± 0.12 | 0.66 ± 0.12 | <0.0001 | |
| PC20 for methacholine—mg/ml | 2.5 ± 3.9 | 2.6 ± 4.5 | 0.6 | |
| FENO—ppb | 37.2 ± 34.8 | 36.5 ± 34.4 | 0.73 | |
| IgE—IU/m | 296.3 ± 631.8 | 260.4 ± 738.2 | 0.42 | |
| Blood neutrophils— ×10 −9 /liter | 4.1 ± 2.0 | 4.5 ± 2.1 | 0.005 | |
| Blood eosinophils— ×10 −9 /liter | 0.8 ± 0.5 | 0.3 ± 0.3 | 0.64 | |
| Sputum Neutrophils–% of differential count | 40.1 ± 25.3 | 51.1 ± 27.0 | <0.0001 | |
| Sputum Eosinophils–% of differential count | 3.0 ± 7.8 | 3.7 ± 10.4 | 0.24 | |
| Neutrophils in BAL–% of differential count | 1.9 ± 3.1 | 2.5 ± 4.5 | 0.03 | |
| Eosinophils in BAL–% of differential count | 0.6 ± 1.3 | 0.7 ± 2.2 | 0.23 | |
* Plus—minus values are means ±SD. BMI denotes body mass index, GERD gastroesophageal reflux disease, FEV1 forced expiratory volume in 1 second, FVC forced vital capacity, PC20 for methacholine the concentration of inhaled methacholine causing a 20% reduction in FEV1, FENO fraction of exhaled nitric oxide, and BAL broncho-alveolar lavage.
† P values are for the comparison of older asthma with the young adult asthma group and were calculated with the use t-test for approximately normally distributed clinical characteristics, Pearson's chi-squared test for differences in proportions, and Wilcoxon signed rank test for all other variables.