Table 2.
Association of Exhalation Time and Participant Characteristics at Years 0, 2 and 5
| Study Year | 0 | 2 | 5 | |||
|---|---|---|---|---|---|---|
| Trials with exhalation time ≥ 6 seconds |
0 | ≥ 1 | 0 | ≥1 | 0 | ≥ 1 |
| Number | 1287 | 3262 | 1269 | 3186 | 397 | 3860 |
| Age – years | 23.9 ± 3.7* | 25.3 ± 3.5 | 26.2 ± 3.7* | 27.2 ± 3.5 | 28.6 ± 3.8* | 30.1 ± 3.6 |
| Male (%) | 35.1* | 50.8 | 29.6* | 51.6 | 30.5* | 46.5 |
| White (%) | 48.0 | 49.9 | 45.2 | 53.4 | 48.1 | 51.9 |
| Education - ≤ high school (%) | 42.9 | 35.9 | 34.2 | 33.4 | 37.3 | 31.1 |
| BMI | 22.6 ± 3.7* | 25.4 ± 5.2 | 23.7 ± 4.8* | 25.7 ± 5.4 | 23.1 ± 5.1* | 26.5 ± 5.9 |
| Smoking - current/previous/never (%) |
27.0/27.8/45.2 | 30.9/30.8/38.3 | 26.3/27.9/45.8 | 30.6/30.9/38.5 | 27.7/26.2/46.1 | 28.6/30.1/41.3 |
| FEV1 - % predicted | 98.8 ± 11.4* | 97.3 ± 11.9 | 98.6 ± 11.4* | 97.1 ± 12.3 | 100.8 ± 15.3** | 99.0 ± 13.0 |
| FVC - % predicted | 98.0 ± 11.3* | 101.2 ± 11.5 | 98.2 ± 11.7* | 101.2 ± 11.7 | 97.7 ± 13.6* | 101.9 ± 12.2 |
| FEV1/FVC | 0.87 ± 0.05* | 0.82 ± 0.06 | 0.86 ± 0.06* | 0.81 ± 0.06 | 0.87 ± 0.08* | 0.81 ± 0.06 |
| Asthma (current) | 4.0 | 4.3 | 4.6 | 4.8 | NA# | NA |
Mean ± SD unless otherwise noted
#
Not available – participants not asked about asthma at this visit
*
p < 0.001,
**
p < 0.02 compared to those at the same study year with at least one exhalation of 6 or more seconds