| |
Methacholine negative (n = 1932)
|
Methacholine positive (n = 305)
|
P value
|
|---|
|
Mean
|
SD
|
Mean
|
SD
|
|---|
|
Age (years)
|
24.10
|
3.65
|
24.50
|
3.80
|
0.16
|
|
Females
|
367 (19%)
|
–
|
67 (22%)
|
–
|
0.22*
|
|
Height (cm)
|
173.60
|
8.29
|
172.89
|
9.16
|
0.18
|
|
Weight (kg)
|
69.53
|
12.26
|
68.77
|
13.50
|
0.36
|
|
BMI (kg/m2)
|
23.01
|
3.44
|
22.80
|
3.46
|
0.56
|
|
Smoking n (%)**
| | | | |
0.26
|
|
Non-smoker
|
176 (67)
| |
42 (67)
| | |
|
Ex-smoker
|
12 (5)
| |
6 (9)
| | |
|
Smoker
|
75 (28)
| |
15 (24)
| | |
|
Total
|
263 (100)
| |
63 (100)
| | |
|
FEV1/FVC ratio (%pred)
|
84.10
|
7.40
|
80.10
|
7.50
|
< 0.01
|
|
FEV1 (%pred)
|
95.40
|
11.00
|
89.10
|
11.70
|
< 0.01
|
|
FEF50% (%pred)
|
89.80
|
22.80
|
75.10
|
18.00
|
< 0.01
|
|
FVC (%pred)
|
99.50
|
13.00
|
96.50
|
13.00
|
< 0.01
|
|
FEF25–75% (%pred)
|
86.90
|
23.10
|
82.70
|
22.80
|
< 0.01
|
|
angle β (°)
|
186.96
|
15.01
|
180.92
|
12.36
|
< 0.01
|
- Methacholine positive defined as PC20 ≤ 16 mg/ml; PC20, Concentration of methacholine causing a 20% decrease in FEV1. BMI, Body Mass Index; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; FEF50%, forced expiratory flow at 50% of FVC; FEF25–75%, forced expiratory flow at 25–75% of FVC; Relative values of spirometry parameters are given as percentage of the predicted value (% pred)
- *P value from Chi-squared analysis
- **Smoking status was available for 326 patients in the derivation cohort—263 from the MCT negative patients and 63 from the MCT positive patients
