Table 2.
The effect of diesel exhaust exposure on wall area percent in all study subjects (n = 154)a
| Variable | Non-DET (n = 76) | DET (n = 78) | Ratio (95CI%) | P |
|---|---|---|---|---|
| 6th wall area percent (%) | ||||
| LB1 + 2 | 54.1 (45.5, 63.9) | 57.4 (50.3, 64.8) | ||
| LB9 | 51.1 (42.8, 59.4) | 56.0 (48.2, 62.8) | ||
| RB9 | 55.3 (46.2, 61.3) | 56.4 (49.5, 63.5) | ||
| RB1 | 53.9 (43.7, 63.6) | 57.0 (50.8, 64.3) | ||
| All | 52.0 (49.9, 54.3) | 55.4 (53.0, 58.0) | 1.07 (1.01, 1.13) | 0.031 |
| 9th wall area percent (%) | ||||
| LB1 + 2 | 41.6 (34.0, 51.4) | 45.1 (35.4, 54.4) | ||
| LB9 | 43.6 (29.9, 54.7) | 45.1 (33.6, 55.0) | ||
| RB9 | 46.5 (33.8, 56.4) | 42.2 (31.0, 56.7) | ||
| RB1 | 45.8 (37.2, 58.9) | 46.6 (38.6, 57.6) | ||
| All | 43.6 (40.7, 46.6) | 44.2 (41.2, 47.5) | 1.02 (0.93, 1.11) | 0.744 |
Definition of abbreviations: CI confidence interval, DET diesel engine testers, LB left bronchus, RB right bronchus
a Linear mixed effects model assessed differences of natural log transformed 6th and 9th wall area percent between non-DETs and DETs with adjustment of age, BMI, smoking history, CT reconstruction method, and lung lobes. Indices were shown as median (Q1, Q3). Ratio = eβ, 95%CI = e(β ± 1.96 × Se). Descriptive statistics for all were exponentials of least square means and 95%CIs that were calculated based on natural log transformed data using linear mixed effects model with adjustment for covariates listed above and may be regarded as an overall level of wall area percent based on the four sampled airways of 6th or 9th generations