Table 1.
Characteristics of the study subjects (N = 703)
| Asthma onset > 12 years, n (%) | |||
|---|---|---|---|
| No | Yes | P | |
| (n = 253) | (n = 450) | ||
| Age, years | 38.8 ± 5.1 | 38.3 ± 4.8 | 0.2 |
| Sex | 0.1 | ||
| Male | 100 (39.5) | 152 (33.8) | |
| Female | 153 (60.5) | 298 (66.2) | |
| BMI | 23.8 ± 3.8 | 23.8 ± 4.0 | 0.9 |
| Education | |||
| Middle school or less | 62 (24.5) | 117 (26.0) | 0.3 |
| High school | 119 (47.0) | 228 (50.7) | |
| College or beyond | 72 (28.5) | 105 (23.3) | |
| Family income | 0.02 | ||
| < 13,300 USD | 75 (29.6) | 180 (40.0) | |
| 13,300–33,000 USD | 147 (58.1) | 228 (50.7) | |
| > 33,000 USD | 31 (12.3) | 42 (9.3) | |
| Current smoking | 62 (25.6) | 96 (21.9) | 0.3 |
BMI body mass index
Regarding current smoking status, the total numbers for asthmatics with age at onset ≤ 12 years and > 12 years were 242 and 438, respectively, because of missing data