Background
Methods
Participants
CT Scanning and quantification of emphysema
Pulmonary function tests
Statistical analysis
Results
Baseline demographics and lung function results
Total n = 3,670
|
Current smoker n= 2,056
|
Quitted <1 year n=284
|
Quitted ≥1 – <5 years n=711
|
Quitted ≥5years n=619
| |
---|---|---|---|---|---|
Age
| 59.8 (5.4) | 58.9 (4.9) | 59.8 (5.3) | 60.4 (5.5) | 62.1 (6.2) |
height (cm)
| 178 (7) | 178 (7) | 179 (7) | 178 (7) | 177 (7) |
FEV
1
/FVC
| 72.2 (9.4) | 72.8 (9) | 72.8 (9.1) | 71.8 (10.2) | 71.9 (9.4) |
FEV
1
[L]
| 3.4 (0.73) | 3.4 (0.8) | 3.4 (0.7) | 3.5 (0.8) | 3.4 (0.7) |
FEV
1
[%]
| 98.5 (18.5) | 99.9 (20) | 100 (18) | 97.1 (19.4) | 97.6 (17.9) |
Packyears
| 40.8 (17.9) | 40.0 (16.4) | 41.0 (17.5) | 43.1 (20.2) | 40.6 (19.5) |
observation time (years)*
| 3.0 (2.9 – 3.1) | 3.0 (2.9-3.1) | 3.0 (2.9-3.1) | 3.0 (2.9-3.1) | 3.0 (2.9-3.1) |
GOLD classification
| |||||
normal (%) | 65.5 | 63.2 | 65.5 | 68.8 | 69.1 |
stage I (%) | 22.0 | 23.4 | 20.4 | 20.8 | 19.2 |
stage II (%) | 10.9 | 11.6 | 12.0 | 9.1 | 10.3 |
stage III (%) | 1.6 | 1.8 | 2.1 | 1.3 | 1.5 |
stage IV (%) | 0.1 | 0.1 | 0 | 0 | 0 |
Presence of respiratory symptoms
| |||||
cough (%) | 32.0 | 46.0 | 24.9 | 14.5 | 10.7 |
wheezing (%) | 23.8 | 33.0 | 20.9 | 13.1 | 7.4 |
dyspnea (%) | 29.5 | 34.4 | 29.5 | 23.3 | 20.8 |
mucus (%) | 30.0 | 39.6 | 26.0 | 17.8 | 15.2 |
lung volume <-950 HU (%)*
| 8.8 (5.1 – 14.1) | 6.8 (3.9 – 11.5) | 10.5 (6.7 – 15.2) | 11.3 (7.4 – 17.2) | 11.9 (7.5 – 16.9) |
lung volume <-910 HU (%)*
| 35.2 (24.1 – 46.0) | 30.2 (20.1 – 41.9) | 38.4 (28.7 – 47.9) | 40.9 (30.6 – 50.7) | 41.2 (31.6 – 51.4) |
perc15 (HU)
| −935 (19) | −930 (21) | −939 (16) | −942 (18) | −942 (17) |
Baseline emphysema
Parameter
|
Effect size
|
p-value.
|
95% CI of effect size
| |
---|---|---|---|---|
Lower bound
|
Upper bound
| |||
Center
| ||||
UMCU | 0.87 | <0.001 | 0.83 | 0.91 |
UMCG (reference) | ||||
smoking group
| ||||
current smoker | 0.60 | <0.001 | 0.56 | 0.64 |
quitted <1 year | 0.90 | 0.033 | 0.81 | 0.99 |
quitted ≥1 – <5 years | 0.99 | 0.956 | 0.93 | 0.99 |
quitted ≥5years (reference) | ||||
baseline GOLD stage
| ||||
normal | 0.17 | 0.013 | 0.04 | 0.68 |
stage I | 0.26 | 0.065 | 0.06 | 1.08 |
stage II | 0.29 | 0.089 | 0.07 | 1.21 |
stage III | 0.46 | 0.279 | 0.11 | 1.89 |
stage IV (reference) | ||||
Presence of respiratory symptoms
| ||||
cough | 0.87 | 0.980 | 0.82 | 0.91 |
wheezing | 0.97 | 0.449 | 0.90 | 1.05 |
dyspnea | 1.00 | 0.786 | 0.94 | 1.08 |
mucus | 1.02 | 0.568 | 0.95 | 1.09 |
height (cm)
| 1.01 | <0.001 | 1.01 | 1.02 |
age at start study (years)
| 1.02 | <0.001 | 1.01 | 1.02 |
packyears
| 0.99 | <0.001 | 0.99 | 1.00 |
Effects on rate of emphysema progression
Parameter
|
Effect size
|
p-value.
|
95% CI of effect size
| |
---|---|---|---|---|
Lower bound
|
Upper bound
| |||
center
| ||||
UMCU | 1.01 | 0.619 | 0.97 | 1.05 |
UMCG (reference) | ||||
smoking group
| ||||
current smoker | 0.60 | <0.001 | 0.56 | 0.64 |
quitted <1 year | 0.91 | 0.083 | 0.82 | 1.01 |
quitted ≥1 – <5 years | 0.99 | 0.868 | 0.92 | 1.07 |
quitted ≥5years (reference) | ||||
baseline GOLD stage
| ||||
normal | 0.18 | 0.002 | 0.06 | 0.54 |
stage I | 0.28 | 0.022 | 0.09 | 0.83 |
stage II | 0.31 | 0.040 | 0.10 | 0.95 |
stage III | 0.47 | 0.183 | 0.15 | 1.43 |
stage IV (reference) | ||||
height (cm)
| 1.01 | <0.001 | 1.07 | 1.01 |
Presence of respiratory symptoms
| ||||
cough | 0.96 | 0.647 | 0.93 | 1.05 |
wheezing | 1.01 | 0.881 | 0.94 | 1.07 |
dyspnea | 0.99 | 0.773 | 0.94 | 1.05 |
mucus | 1.02 | 0.724 | 0.96 | 1.09 |
age at start study (years)
| 1.02 | <0.001 | 1.01 | 1.02 |
packyears
| 0.99 | <0.001 | 0.97 | 0.99 |
observation time
| 1.07 | <0.001 | 1.06 | 1.09 |
observation time * smoking group
| ||||
current smoker | 1.05 | <0.001 | 1.03 | 1.07 |
quitted <1 year | 0.99 | 0.799 | 0.97 | 1.02 |
quitted ≥1 – <5 years | 0.99 | 0.234 | 0.97 | 1.01 |
quitted ≥5years (reference) |
Effects on FEV1-decline
Parameter
|
Effect size
|
p-value.
|
95% CI of effect size
| |
---|---|---|---|---|
Lower bound
|
Upper bound
| |||
center
| ||||
UMCU | -.74.4 | <0.001 | −103 | 46 |
UMCG (reference) | ||||
smoking group
| ||||
current smoker | −101 | <0.001 | −142 | −61 |
quitted <1 year | −68 | 0.033 | −130 | −5 |
quitted ≥1 – <5 years | −32 | 0.188 | −80 | 15 |
quitted ≥5years (reference) | ||||
baseline GOLD stage
| ||||
normal | 2346 | <0.001 | 1497 | 3195 |
stage I | 2035 | <0.001 | 1185 | 2884 |
stage II | 1187 | 0.006 | 337 | 2037 |
stage III | 346 | 0.428 | −510 | 1202 |
stage IV (reference) | ||||
height (cm)
| 044 | <0.001 | 41 | 46 |
Presence of respiratory symptoms
| ||||
cough | −11 | 0.607 | −7 | 19 |
wheezing | −106 | <0.001 | −152 | −60 |
dyspnea | −76 | <0.001 | −117 | −34.7 |
mucus | 12 | 0.580 | −30 | 54 |
age at start study (years)
| −29 | <0.001 | −32 | −27 |
packyears
| −3.2 | <0.001 | −4 | −2 |
observation time
| −58 | <0.001 | −66 | −48 |
observation time * smoking group
| ||||
current smoker | −12 | 0.029 | −22 | −1 |
quitted <1 year | −19 | 0.019 | −35 | −3 |
quitted ≥1 – <5 years | 0.8 | 0.237 | −5 | 20 |
quitted ≥5years (reference) |