Background
Methods
Study Population
Data sources
Symptoms
Lung function
Airway responsiveness
Atopy
Indoor allergen exposure
Definition of outcomes and exposures
Current asthma
Airway hyperresponsiveness (AHR)
Allergic sensitisation as a dichotomous variable
Tobacco smoking
Allergen exposure
Statistical analysis
Results
Participants
Variable | Total (n)* | % of Total Subjects | ||
---|---|---|---|---|
Age (y)
|
Mean
|
(Range)
| ||
48.3 | (19.8-72.9) | 983 | 100.0 | |
Gender - male
|
n
|
(%)
| ||
416 | (42.3) | 983 | 100.0 | |
BMI (%)
|
Mean
|
(SD)
| ||
27.2 | 5.1 | 769 | 78.2 | |
Asthma
|
n
|
(%)
| ||
Current Asthma
| 312 | (31.74) | 983 | 100.0 |
Airway Hyperresponsiveness (AHR)
|
n
|
(%)
| ||
AHR-MDRS>25
| 100 | (15.97) | 626 | 63.7 |
GM
|
(Range)
| |||
MDRS
| 8.229 | (0.0-17592.5) | 626 | 63.7 |
Current Asthma with AHR
|
n
|
(%)
| ||
Current Asthma + AHR-MDRS>25
| 64 | (10.22) | 626 | 63.7 |
Lung Function
|
Mean
|
(SD)
| ||
FVC % predicted
| 111.86 | (16.01) | 790 | 80.4 |
FEV
1
% predicted
| 101.20 | (18.41) | 792 | 80.6 |
FEV
1
/FVC
| 75.84 | (8.71) | 790 | 80.4 |
Atopy
|
n
|
(%)
| ||
SPT
| 402 | 55.07 | 730 | 74.3 |
sIgE
| 473 | 63.24 | 748 | 76.1 |
Smoking
|
n
|
(%)
| ||
Ever smokers
| 396 | (40.28) | 983 | 100.0 |
Current smokers
| 114 | (11.60) | 983 | 100.0 |
GM
|
(Range)
| |||
Smoke-pack-years
| 0.0006 | (0.0 -104.59) | 981 | 99.8 |
Pet ownership
|
n
|
(%)
| ||
Cat owner (current)
| 171 | 21.22 | 806 | 81.99 |
Dog owner (current)
| 142 | 17.62 | 806 | 81.99 |
Cat or dog owner (current)
| 277 | 34.37 | 806 | 81.99 |
Indoor allergen exposure (μg/g) |
GM
|
(Range)
| ||
Mite (Der p 1)
| 2.59 | (0.20-188.67) | 953 | 96.95 |
Cat (Fel d 1)
| 1.42 | (0.04-5377.61) | 951 | 96.75 |
Dog (Can f 1)
| 0.96 | 0.20-3361.02) | 948 | 96.44 |
Dichotomous | Quantitative | Total (n) | % of Total Subjects | |||
---|---|---|---|---|---|---|
SPT | n | (%) | Median* | (Range) | ||
Mite
| 256 | (35.07) | 4.5 | (0-19.5) | 730 | 74.26 |
Cat
| 175 | (23.97) | 4.5 | (0-20.0) | 730 | 74.26 |
Dog
| 112 | (15.34) | 4.0 | (0-16.5) | 730 | 74.26 |
Tree pollen mix
| 84 | (14.43) | 5.0 | (0-11.0) | 582 | 59.21 |
Grass pollen mix
| 213 | (29.18) | 5.0 | (0-23.0) | 730 | 74.26 |
Mould mix
| 32 | (4.40) | 4.0 | (0-12.0) | 727 | 73.96 |
Specific IgE
|
n
|
(%)
|
GM
|
(Range)
| ||
Mite
| 343 | (45.86) | 0.48 | (0.05-160.77) | 748 | 76.09 |
Cat
| 211 | (28.21) | 0.16 | (0.05-146.94) | 748 | 76.09 |
Dog
| 170 | (22.73) | 0.14 | (0.05-100.48) | 748 | 76.09 |
Grass pollen mix
| 336 | (44.92) | 2.18 | (0.05-407.48) | 748 | 76.09 |
Allergen | Spearman's rho | p value |
---|---|---|
Mite
| 0.734 | 3.63 × 10-116 |
Cat
| 0.696 | 1.36 × 10-99 |
Dog
| 0.548 | 1.85 × 10-54 |
Grass pollen
| 0.644 | 5.51 × 10-81 |
Specific IgE, Skin Prick tests and Lung Function
FEV1 % predicted | FVC % predicted | FEV1/FVC | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Associate | P | Slope | R2 | P | Slope | R2 | P | Slope | R2 | |
Atopy on SPT*
| 0.00001 | -5.93 | 0.03 | 0.03 | -2.61 | 0.007 | 5.39×10-8 | -9.81 | 0.03 | |
Mite |
Positive SPT
| 0.00001 | -6.27 | 0.03 | 0.01 | -3.25 | 0.009 | 6.17×10-7 | -9.76 | 0.03 |
SPT-WMD
| 8.23×10-8 | -1.40 | 0.04 | 0.002 | -0.75 | 0.01 | 4.12×10-9 | -2.11 | 0.05 | |
Cat |
Positive SPT
| 5.02×10-7 | -7.69 | 0.03 | 0.02 | -2.96 | 0.007 | 1.08×10-7 | -13.61 | 0.05 |
SPT-WMD
| 3.93×10-10 | -1.63 | 0.05 | 0.0007 | -0.81 | 0.02 | 2.80×10-10 | -2.55 | 0.06 | |
Dog |
Positive SPT
| 4.16×10-12 | -12.22 | 0.06 | 0.0001 | -6.06 | 0.02 | 1.38×10-13 | -18.21 | 0.07 |
SPT-WMD
| 3.03×10-15 | -2.49 | 0.08 | 1.70×10-6 | -1.41 | 0.03 | 8.53×10-16 | -3.68 | 0.09 | |
Tree |
Positive SPT
| 0.73 | 0.52 | 0.0002 | 0.51 | 0.97 | 0.0008 | 0.85 | -1.36 | 0.0005 |
SPT-WMD
| 0.93 | -0.07 | 0.00001 | 0.70 | 0.02 | 0.0003 | 0.37 | -0.51 | 0.002 | |
Grass |
Positive SPT
| 2.06×10-6 | -6.78 | 0.03 | 0.004 | -3.64 | 0.01 | 2.79×10-7 | -9.40 | 0.03 |
SPT-WMD
| 2.95×10-9 | -1.04 | 0.05 | 0.0002 | -0.59 | 0.02 | 9.62×10-10 | -1.50 | 0.05 | |
Mould |
Positive SPT
| 0.22 | -3.22 | 0.002 | 0.61 | -1.10 | 0.0004 | 0.17 | -8.17 | 0.005 |
SPT-WMD
| 0.02 | -1.53 | 0.007 | 0.24 | -0.77 | 0.002 | 0.006 | -2.60 | 0.01 | |
Atopy on sIgE
#
| 0.0007 | -4.83 | 0.02 | 0.10 | -2.03 | 0.004 | 0.0001 | -7.22 | 0.02 | |
Mite |
Positive sIgE
| 0.03 | -2.97 | 0.006 | 0.45 | -0.89 | 0.0008 | 0.008 | -5.31 | 0.01 |
sIgE level
| 0.001 | -0.88 | 0.01 | 0.21 | -0.30 | 0.002 | 0.0004 | -1.49 | 0.02 | |
Cat |
Positive sIgE
| 0.0007 | -5.16 | 0.02 | 0.57 | -0.75 | 0.0004 | 0.00006 | -11.76 | 0.04 |
sIgE level
| 0.0001 | -1.37 | 0.02 | 0.28 | -0.33 | 0.002 | 0.00003 | -2.78 | 0.04 | |
Dog |
Positive sIgE
| 8.57×10-8 | -8.70 | 0.04 | 0.02 | -3.39 | 0.008 | 7.30×10-8 | -16.05 | 0.06 |
sIgE level
| 2.95×10-8 | -2.29 | 0.04 | 0.004 | -1.04 | 0.01 | 1.96×10-7 | -3.87 | 0.06 | |
Grass |
Positive sIgE
| 0.04 | -2.82 | 0.006 | 0.72 | -0.42 | 0.0002 | 0.002 | -5.83 | 0.01 |
sIgE level
| 0.15 | -0.38 | 0.003 | 0.82 | -0.05 | 0.00007 | 0.05 | -0.84 | 0.006 | |
Gender - Female
| 0.09 | 2.27 | 0.004 | 1.00×10-6 | 5.66 | 0.03 | 0.0009 | 0.02 | 0.01 | |
Age (years)
| 1.22×10-13 | -0.62 | 0.07 | 3.29×10-6 | -0.30 | 0.03 | 1.31×10-31 | -0.005 | 0.16 | |
BMI (%)
| 0.0008 | -0.42 | 0.01 | 4.80×10-9 | -0.64 | 0.04 | 0.36 | 0.001 | 0.001 | |
Current Asthma
| 1.18×10-41 | -17.46 | 0.21 | 3.05×10-13 | -8.53 | 0.07 | 3.68×10-43 | -0.08 | 0.21 | |
Cat ownership (current)
| 0.32 | -1.65 | 0.001 | 0.96 | -0.12 | 2.54×10-6 | 0.10 | -0.01 | 0.003 | |
Dog ownership (current)
| 0.25 | -1.99 | 0.002 | 0.68 | -0.60 | 0.0002 | 0.14 | -0.01 | 0.003 | |
Ln Der p 1 Exposure (μg/g)
| 0.62 | 0.17 | 0.0003 | 0.33 | 0.29 | 0.001 | 0.68 | -0.001 | 0.0002 | |
Ln Fel d 1 Exposure (μg/g)
| 0.39 | -0.22 | 0.0010 | 0.77 | 0.08 | 0.0001 | 0.01 | -0.003 | 0.008 | |
Ln Can f 1 Exposure (μg/g)
| 0.0001 | -1.22 | 0.02 | 0.002 | -0.87 | 0.01 | 0.003 | -0.005 | 0.01 | |
Smoking (Ever)
| 0.0008 | -4.46 | 0.01 | 0.07 | -2.08 | 0.004 | 0.0001 | -0.02 | 0.02 | |
Ln Smoke-Pack-Years
| 0.0002 | -0.31 | 0.02 | 0.03 | -0.16 | 0.006 | 0.0001 | -0.002 | 0.02 |
Specific IgE, Skin prick tests and Airway Hyperresponsiveness
tMDRS | ||||
---|---|---|---|---|
Associate
| p | Slope | R2 | |
Atopy on SPT*
| 4.27×10-11 | -1.43 | 0.07 | |
Mite |
Positive SPT
| 1.05×10-9 | -1.43 | 0.06 |
SPT-WMD
| 1.28×10-12 | 0.033 | 0.08 | |
Cat |
Positive SPT
| 4.31×10-9 | -1.55 | 0.06 |
SPT-WMD
| 3.09×10-11 | -0.38 | 0.07 | |
Dog |
Positive SPT
| 4.30×10-12 | -2.32 | 0.08 |
SPT-WMD
| 3.95×10-12 | -0.51 | 0.08 | |
Tree |
Positive SPT
| 0.0001 | -1.19 | 0.03 |
SPT-WMD
| 0.0001 | -0.23 | 0.03 | |
Grass |
Positive SPT
| 1.27×10-7 | -1.31 | 0.05 |
SPT-WMD
| 5.80×10-8 | -0.27 | 0.05 | |
Mould |
Positive SPT
| 0.003 | -1.92 | 0.02 |
SPT-WMD
| 0.002 | -0.48 | 0.02 | |
Atopy on sIgE
#
| 3.14×10-14 | -1.72 | 0.10 | |
Mite |
Positive sIgE
| 1.04×10-11 | -1.54 | 0.08 |
sIgE level
| 3.08×10-17 | -0.39 | 0.12 | |
Cat |
Positive sIgE
| 4.83×10-16 | -2.08 | 0.11 |
sIgE level
| 4.83×10-16 | -0.57 | 0.14 | |
Dog |
Positive sIgE
| 2.55×10-21 | -2.59 | 0.15 |
sIgE level
| 2.42×10-23 | -0.72 | 0.16 | |
Grass |
Positive sIgE
| 7.73×10-13 | -1.61 | 0.09 |
sIgE level
| 1.44×10-13 | -0.33 | 0.09 | |
Gender - Female
| 1.07×10-7 | -1.17 | 0.04 | |
Age (years)
| 0.39 | -0.04 | 0.001 | |
BMI (%)
| 0.14 | -0.03 | 0.004 | |
FEV
1
% predicted
| 2.55×10-28 | 0.08 | 0.18 | |
FVC % predicted
| 0.001 | 0.03 | 0.02 | |
FEV
1
/FVC
| 1.18×10-27 | 15.79 | 0.18 | |
Current Asthma
| 3.30×10 -32 | -2.89 | 0.20 | |
Cat ownership (current)
| 0.42 | 0.24 | 0.001 | |
Dog ownership (current)
| 0.04 | -0.61 | 0.007 | |
Ln Der p 1 Exposure (μg/g)
| 0.77 | 0.02 | 0.0001 | |
Ln Fel d 1 Exposure (μg/g)
| 0.26 | 0.06 | 0.002 | |
Ln Can f 1 Exposure (μg/g)
| 0.02 | -0.13 | 0.009 | |
Smoking (Ever)
| 0.08 | -0.40 | 0.005 | |
Ln Smoke-Pack-Years
| 0.08 | -0.03 | 0.005 |
Specific IgE antibodies, Skin Test Size and Lung Function and Airway Hyperresponsiveness amongst sensitised subjects
FEV1 % predicted | tMDRS | |||||
---|---|---|---|---|---|---|
p | Slope | R2 | p | Slope | R2 | |
SPT-WMD
| ||||||
Mite | 0.001 | -1.33 | 0.04 | 0.001 | -0.19 | 0.03 |
Cat | 2.26×10-6 | -1.41 | 0.05 | 1.57×10-5 | -0.27 | 0.06 |
Dog | 3.69×10-11 | -2.43 | 0.1 | 2.64×10-6 | -0.37 | 0.07 |
Tree | 0.84 | 0.07 | 0.0001 | 0.08 | -0.12 | 0.01 |
Grass | 3.77×10-6 | -1.04 | 0.05 | 0.03 | -0.11 | 0.01 |
Mould | 0.17 | -0.99 | 0.005 | 0.09 | -0.29 | 0.009 |
sIgE
| ||||||
Mite | 0.09 | -0.50 | 0.004 | 6.08×10-6 | -0.28 | 0.06 |
Cat | 0.01 | -1.05 | 0.01 | 1.14×10-10 | -0.46 | 0.12 |
Dog | 9.33×10-6 | -2.08 | 0.04 | 2.90×10-12 | -0.59 | 0.13 |
Grass | 0.35 | 0.34 | 0.002 | 0.02 | -0.19 | 0.03 |
Multivariate analysis
FEV1 % predicted | ||||
---|---|---|---|---|
Associate | Model 1 (SPT-WMD) | Model 2 (sIgE level) | ||
Adj p | Adj R2 | Adj p | Adj R2 | |
Age
| 5.82×10-7 | 0.04 | 5.91×10-8 | 0.04 |
BMI
| 0.09 | 0.48 | ||
Current Asthma
| 1.64×10-14 | 0.08 | 3.34×10-24 | 0.14 |
Ln Smoke-Pack-Years
| 0.02 | 0.008 | 0.02 | 0.008 |
Ln Can f 1 exposure
| 0.06 | 0.07 | ||
Mite
| 0.16 | 0. 69 | ||
Cat
| 0.91 | 0.46 | ||
Dog
| 0.003 | 0.01 | 0.10 | |
Grass
| 1.00 | NI | ||
Mould
| 0.11 | NA | ||
FVC % predicted
| ||||
Associate
|
Model 1 (SPT-WMD)
|
Model 2 (sIgE level)
| ||
Adj p
|
Adj R
2
|
Adj p
|
Adj R
2
| |
Age
| 0.01 | 0.009 | 0.01 | 0.009 |
BMI
| 3.65×10-5 | 0.03 | 6.23×10-5 | 0.02 |
Gender - female
| 0.0003 | 0.02 | 0.001 | 0.02 |
Current Asthma
| 0.0002 | 0.02 | 2.91×10-8 | 0.04 |
Ln Smoke-Pack-Years
| 0.44 | 0.45 | ||
Ln Can f 1 exposure
| 0.18 | 0.13 | ||
Mite
| 0.49 | NI | ||
Cat
| 0.91 | NI | ||
Dog
| 0.047 | 0.006 | 0.56 | |
Grass
| 0.94 | NI | ||
FEV
1
/FVC
| ||||
Associate
|
Model 1 (SPT-WMD)
|
Model 2 (sIgE level)
| ||
Adj p
|
Adj R
2
|
Adj p
|
Adj R
2
| |
Age
| 9.99×10-20 | 0.12 | 2.51×10-23 | 0.13 |
Gender - female
| 0.02 | 0.008 | 0.01 | 0.009 |
Current Asthma
| 8.08×10-15 | 0.09 | 8.52×10-21 | 0.12 |
Ln Smoke-Pack-Years
| 0.004 | 0.01 | 0.004 | 0.01 |
Ln Can f 1 exposure
| 0.20 | 0.33 | ||
Ln Fel d 1 exposure
| 0.27 | 0.24 | ||
Mite
| 0.02 | 0.008 | 0.21 | |
Cat
| 0.84 | 0.72 | ||
Dog
| 0.003 | 0.01 | 0.47 | |
Grass
| 0.96 | NI | ||
Mould
| 0.23 | NA | ||
tMDRS
| ||||
Associate
|
Model 1 (SPT-WMD)
|
Model 2 (sIgE level)
| ||
Adj p
|
Adj R
2
|
Adj p
|
Adj R
2
| |
Gender - female
| 3.59×10-13 | 0.09 | 3.97×10-13 | 0.09 |
Current Asthma
| 3.82×10-7 | 0.05 | 0.0003 | 0.02 |
FEV
1
% predicted
| 60.3×10-9 | 0.06 | 1.04×10-8 | 0.06 |
FEV
1
/FVC
| 0.001 | 0.02 | 2.05×10-5 | 0.03 |
Ln Can f 1 exposure
| 0.25 | 0.32 | ||
Mite
| 0.0001 | 0.03 | 0.0004 | 0.02 |
Cat
| 0.36 | 0.45 | ||
Dog
| 0.56 | 0.44 | ||
Grass
| 0.20 | 0.007 | 0.01 | |
Mould
| 0.30 | NA |