|
Wall area percent
|
CCAM
|
N (DET)
|
Mean (95%CI)
|
Ratio (95%CI)
|
P
|
|---|
|
Category
|
Range (%)
|
|---|
|
6th generation (%)
|
1
|
0.24–1.33
|
21 (2)
|
49.7 (45.9, 53.7)
|
Ref
| |
| |
2
|
1.33–1.92
|
21 (4)
|
54.3 (50.1, 58.9)
|
1.09 (0.98, 1.22)
|
0.102
|
| |
3
|
1.92–3.10
|
21 (9)
|
53.0 (49.0, 57.1)
|
1.07 (0.96, 1.19)
|
0.249
|
| |
4
|
3.10–4.70
|
21 (18)
|
52.0 (48.1, 56.3)
|
1.05 (0.94, 1.17)
|
0.391
|
| |
5
|
4.70–30.24
|
22 (20)
|
56.8 (52.5, 61.3)
|
1.14 (1.03, 1.27)
|
0.015
|
|
Trend testb
| | | | |
1.02 (1.00, 1.05)
|
0.063
|
|
9th generation (%)
|
1
|
0.24–1.33
|
21 (2)
|
39.4 (35.1, 44.3)
|
Ref
| |
| |
2
|
1.33–1.92
|
21 (4)
|
45.3 (40.2, 51.1)
|
1.15 (0.98, 1.35)
|
0.085
|
| |
3
|
1.92–3.10
|
21 (9)
|
43.9 (39.2, 49.1)
|
1.11 (0.95, 1.31)
|
0.195
|
| |
4
|
3.10–4.70
|
21 (18)
|
43.0 (38.3, 48.3)
|
1.09 (0.93, 1.28)
|
0.287
|
| |
5
|
4.70–30.24
|
22 (20)
|
45.1 (40.2, 50.6)
|
1.14 (0.98, 1.34)
|
0.098
|
|
Trend testb
| | | | |
1.02 (0.99, 1.06)
|
0.239
|
- Definition of abbreviations: CCAM carbon content in airway macrophage, CI confidence interval, DET diesel engine tester, LsMean least square mean, Ref reference
- a Linear mixed effects model assessed differences of natural log transformed 6th and 9th wall area percent between categories 2–5 and the reference group (category 1) with adjustment of age, BMI, smoking history, CT reconstruction method, and lung lobes. Mean and 95%CI are exponentials of least square means and 95%CIs calculated based on natural log transformed data. Ratio = eβ, 95%CI = e(β ± 1.96 × Se)
- b Linear mixed effects model assessed dose – response relation between CCAM category coded as 0, 1, 2, 3, and 4 and natural log transformed 6th and 9th wall area percent with adjustment for covariates listed above
