Online supporting information for the following article
published in Indoor Air
DOI: 10.1111/ina.12137
House dust mite allergen exposure is associated with
serum specific IgE but not with respiratory outcomes
Bakolis I¹, Heinrich J2, Zock JP3,4,5, Norbäck D6, Svanes C8, Chen CM2,
Accordini S9, Verlato G9 , Olivieri M10, Jarvis D7,11
1
Small Area Health Statistics Unit, MRC-HPA Centre for Environment and Health,
Department of Epidemiology and Biostatistics, School of Public Health, Imperial
College London
2
Helmholtz Zentrum München, German ResearchCentre for Environmental Health,
Institute of Epidemiology I, Neuherberg, Germany
3
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain
4
Universitat Pompeu Fabra (UPF), Barcelona, Spain
5
CIBER Epidemiologia y Salud Pública (CIBERESP), Spain
6
The Dept of Medical Science, Occupational and Environmental Medicine, Uppsala
University, SE-751 85 Uppsala, Sweden
7
MRC-HPA Centre for Environment and Health
8
Bergen Respiratory ResearchGroup, Centre for International Health, University of
Bergen
9
Epidemiology and Medical Statistics, University of Verona, Verona, Italy
10
Unit of Occupational Medicine, University Hospital of Verona, Verona, Italy
11
Respiratory Epidemiology and Public Health Group, National Heart and Lung,
Institute Imperial College London
Corresponding author
Ioannis Bakolis
Imperial College London
School of Public Health
Department of Epidemiology and Biostatistics
Norfolk Place
London W2 1PG
United Kingdom
Email: i.bakolis@imperial.ac.uk
1
Table S1. Percentage of people with IgE titre levels (cut-of point of IgE level above
0.35 KUA/L, 0.70KUA/L and 3.5KUA/L) considered as positive to House dust mite
(HDM) and Cat.
N=2890
centre
South
Antwerp
Antwerp
City
Hamburg
Erfurt
Barcelona
Galdakao
Albacete
Oviedo
Huelva
Grenoble
Paris
Pavia
Turin
Verona
Ipswich
Norwich
Reykjavik
Goteborg
Umea
Uppasala
Basel
Tartu
Total
IgE positive to HDM
0.35
0.70
KU/L
KU/L
Freq. (% ) Freq (% )
.
28
20.7
20
14.8
IgE positive to Cat
0.70
3.5
KU/L
KU/L
(% ) Freq. (% ) Freq.
(%)
3.5
KU/L
Freq.
(%)
0.35
KU/L
Freq.
12
8.9
11
8.1
7
5.2
4
3.0
17
22.1
16
20.8
10
13.0
6
7.8
6
7.8
4
5.2
23
16
23
26
6
20
17
24
40
11
11
17
27
34
8
8
4
9
18
22
409
15.1
8.6
21.3
17.7
5.3
16.5
20.2
15.7
25.5
25.0
25.0
18.7
33.8
26.4
5.0
6.3
3.1
7.6
21.4
13.0
13
8
18
24
4
15
15
16
30
6
7
14
22
26
5
6
3
5
14
15
302
8.6
4.3
16.7
16.3
3.5
12.4
17.9
10.5
19.1
13.6
15.9
15.4
27.5
20.2
3.1
4.7
2.3
4.2
16.7
8.9
5
2
8
13
2
9
8
7
18
2
2
7
13
14
3
3
0
1
7
6
152
3.3
1.1
7.4
8.8
1.8
7.4
9.5
4.6
11.5
4.5
4.5
7.7
16.3
10.9
1.9
2.4
0.0
0.8
8.3
3.6
12
14
4
7
6
7
6
18
13
2
4
8
9
13
11
15
19
21
9
11
226
7.9
7.5
3.7
4.8
5.3
5.8
7.1
11.8
8.3
4.5
9.1
8.8
11.3
10.1
6.9
11.8
14.8
17.6
10.7
6.5
6
9
4
2
5
6
4
11
6
1
1
6
7
10
8
11
14
19
7
9
159
3.9
4.8
3.7
1.4
4.4
5.0
4.8
7.2
3.8
2.3
2.3
6.6
8.8
7.8
5.0
8.7
10.9
16.0
8.3
5.3
4
4
2
2
2
3
0
4
5
1
0
0
4
5
5
6
9
10
2
4
80
2.6
2.2
1.9
1.4
1.8
2.5
0.0
2.6
3.2
2.3
0.0
0.0
5.0
3.9
3.1
4.7
7.0
8.4
2.4
2.4
2
Table S2. Unadjusted and adjusted associations (95% CI) of specific IgE titre to grass
with Der1 allergen levels in mattress dust
- grass pollen
(cut off>0.35 KUA/L)
0.1 to 0.76
0.77 to 4.01
4.02 to 16.3
>16.3
P for trend
(cut off>0.70 KUA/L)
0.1 to 0.76
0.77 to 4.01
4.02 to 16.3
>16.3
P for trend
(cut off>3.5 KUA/L)
0.1 to 0.76
0.77 to 4.01
4.02 to 16.3
>16.3
P for trend
(n=2607)
1.13 (0.79, 1.62)
0.96 ( 0.67 ,1.40 )
1.03 (0.70,1.51)
0.88(0.57,1.33)
0.506
(n=2541)
1.02 (0.70, 1.50)
0.90 ( 0.60 ,1.34 )
1.04 (0.69,1.56)
0.80(0.51,1.27)
0.490
(n=2412)
0.83 (0.52, 1.33)
0.65 (0.40 ,1.11)
0.90 (0.56,1.47)
0.64(0.36,1.13)
0.213
(n=2418)
1.08 (0.74, 1.57)
0.89 ( 0.60 ,1.32 )
0.99(0.66,1.48)
0.78(0.49,1.23)
0.295
(n=2418)
0.95 (0.63,1.43)
0.86 ( 0.56 ,1.31)
0.97(0.63,1.50)
0.71(0.43,1.16)
0.284
(n=2418)
0.73 (0.44,1.20)
0.56 (0.33 ,0.95)
0.79 (0.47,1.34)
0.55(0.30,1.01)
0.113
3
Table S3: Percentages (%) of asthma score for each category of Der1 allergen
levels in mattress dust.
Asthma score
0
0
646
32.46
Categories of Der1 levels
1
2
3
4
329
348
335
332
16.53
17.49
16.83
16.68
1
160
29.41
92
16.91
103
18.93
98
18.01
91
16.73
544
100
2
70
34.83
28
32.18
39
19.4
16
18.39
29
14.43
19
21.84
30
14.93
11
12.64
33
16.42
13
14.94
201
100
87
100
4
18
40.91
6
13.64
5
11.36
7
15.91
8
18.18
44
100
5
6
25
5
20.83
3
12.5
4
16.67
6
25
24
100
Total
928
32.11
487
16.85
507
17.54
485
16.78
483
16.71
2,890
100
3
Total
1,990
100
4
Table S4. Estimation of power for different effect sizes and different prevalence
of potential respiratory and allergic outcomes at the 5% level of significance. We
are comparing two groups in a logistic regression analysis (unbalanced size of
groups (n1=928 and n2=483)). Power calculations are employed with the use of
simsam command in STATA (Hooper R., 2013).
Prevalence
15%
25%
35%
1.2
1.3
65.2%
73.1%
84.8%
79.3%
82.3%
90.4%
Odds ratio
1.4
1.6
82.2%
93.1%
96.4%
2
95.4% 99.1%
99.3% 100%
100% 100%
HOOPER, R., 2013. Versatile sample-size calculation using simulation. Stata Journal, 13(1), pp.
21-38.
5
Figure S1: Fixed and random effect meta-analysis of the relationship between IgE
sensitization to cat and Der1 allergen levels adjusted for smoking status and household
variables (cut-of point of IgE level to cat>0.35 KUA/L ).
%
odds
Weight
centre
ratio (95% CI)
(D+L)
South Antwerp
1.20 (0.67, 2.15)
8.00
Antwerp City
0.75 (0.33, 1.71)
3.96
Hamburg
1.20 (0.60, 2.41)
5.61
Erfurt
0.70 (0.36, 1.35)
6.24
Barcelona
2.94 (0.67, 12.88)
1.24
Galdakao
0.53 (0.19, 1.48)
2.61
Oviedo
0.49 (0.23, 1.05)
4.58
Huelva
0.81 (0.33, 1.98)
3.42
Grenoble
1.07 (0.71, 1.62)
15.68
Paris
0.94 (0.55, 1.62)
9.20
Verona
0.95 (0.44, 2.07)
4.47
Ipswich
0.88 (0.32, 2.36)
2.75
Norwich
0.64 (0.35, 1.19)
7.15
Goteborg
0.89 (0.51, 1.57)
8.63
Umea
2.05 (0.72, 5.87)
2.45
Uppasala
0.83 (0.37, 1.83)
4.30
Basel
0.81 (0.40, 1.66)
5.35
Tartu
0.61 (0.28, 1.35)
4.36
D+L Overall (I-squared = 0.0%, p = 0.700)
0.89 (0.75, 1.05)
100.00
I-V Overall
0.89 (0.75, 1.05)
NOTE: Weights are from random effects analysis
.25
.5
1
2
10
cut-off level of IgE to cat>0.35 KU/L
Reykjavik, Albacete, Pavia and Turin were dropped due to limited observations (low prevalence
of sensitisation to cat)
6
Figure S2: Fixed and random effect meta-analysis of the relationship between IgE
sensitization to cat and Der1 allergen levels adjusted for smoking status and household
variables (cut-of point of IgE level to cat>0.70KUA/L).
%
odds
Weight
centre
ratio (95% CI)
(D+L)
South Antwerp
3.26 (1.15, 9.25)
5.36
Antwerp City
0.75 (0.33, 1.71)
7.57
Hamburg
1.95 (0.58, 6.50)
4.24
Erfurt
0.95 (0.46, 1.94)
9.15
Barcelona
2.94 (0.67, 12.88)
2.98
Oviedo
0.55 (0.24, 1.27)
7.47
Huelva
1.61 (0.35, 7.38)
2.84
Grenoble
0.88 (0.51, 1.51)
12.66
Paris
1.38 (0.54, 3.51)
6.35
Verona
1.85 (0.62, 5.50)
4.99
Ipswich
0.52 (0.14, 1.90)
3.73
Norwich
0.48 (0.21, 1.07)
7.92
Goteborg
0.56 (0.23, 1.37)
6.82
Uppasala
0.33 (0.05, 2.20)
1.93
Basel
1.07 (0.49, 2.34)
8.23
Tartu
0.70 (0.31, 1.57)
7.76
D+L Overall (I-squared = 25.9%, p = 0.163)
0.94 (0.71, 1.23)
100.00
I-V Overall
0.92 (0.73, 1.15)
NOTE: Weights are from random effects analysis
.25
.5
1
2
10
cut-off level of IgE to cat >0.70 KU/L
Reykjavik, Umea, Galdakao and Albacete were dropped due to limited observations (low
prevalence of sensitisation to cat)
7
Figure S3: Fixed and random effect meta-analysis of the relationship between IgE
sensitization to cat and Der1 allergen levels adjusted for smoking status and household
variables (cut-of point of IgE level to cat> 3.5 KUA/L).
%
odds
Weight
centre
ratio (95% CI)
(D+L)
South Antwerp
4.52 (0.93, 21.87)
10.73
Hamburg
1.97 (0.48, 8.19)
12.34
Erfurt
0.53 (0.11, 2.55)
10.86
Oviedo
0.11 (0.01, 1.28)
5.40
Grenoble
0.51 (0.11, 2.45)
10.83
Paris
1.43 (0.51, 4.05)
17.77
Norwich
0.52 (0.20, 1.36)
19.19
Tartu
1.00 (0.25, 3.95)
12.88
Antwerp City
(Excluded)
0.00
Barcelona
(Excluded)
0.00
Galdakao
(Excluded)
0.00
Ipswich
(Excluded)
0.00
Reykjavik
(Excluded)
0.00
Goteborg
(Excluded)
0.00
Umea
(Excluded)
0.00
Uppasala
(Excluded)
0.00
D+L Overall (I-squared = 36.2%, p = 0.140)
0.93 (0.50, 1.72)
100.00
I-V Overall
0.93 (0.58, 1.49)
NOTE: Weights are from random effects analysis
.25
.512 10
cut-off level of IgE to cat >3.5 KU/L
8
Figure S4: Fixed and random effect meta-analysis of the relationship between asthma score
(log linear) and Der1 allergen levels adjusted for smoking status and household variables
%
centre
ES (95% CI)
Weight
South Antwerp
-0.14 (-0.51, 0.23)
3.84
Antwerp City
0.14 (-0.20, 0.49)
4.28
Hamburg
0.04 (-0.13, 0.22)
11.22
Erfurt
0.05 (-0.16, 0.26)
9.19
Barcelona
0.17 (-0.14, 0.47)
5.26
Galdakao
-0.28 (-0.77, 0.20)
2.39
Albacete
-0.94 (-1.81, -0.06)
0.79
Oviedo
-0.03 (-0.34, 0.27)
5.26
Huelva
0.25 (0.03, 0.48)
8.37
Grenoble
-0.09 (-0.34, 0.16)
7.11
Paris
-0.07 (-0.27, 0.12)
9.90
Pavia
-0.20 (-0.66, 0.26)
2.62
Turin
-0.34 (-0.77, 0.09)
2.96
Verona
0.07 (-0.28, 0.41)
4.38
Ipswich
-0.09 (-0.41, 0.23)
4.93
Norwich
-0.06 (-0.30, 0.19)
7.28
Goteborg
-0.21 (-0.59, 0.16)
3.77
Umea
-0.94 (-2.92, 1.05)
0.16
Uppasala
-0.04 (-0.55, 0.46)
2.22
Tartu
-0.36 (-0.72, -0.01)
4.07
Overall (I-squared = 20.9%, p = 0.195)
-0.04 (-0.11, 0.04)
100.00
NOTE: Weights are from random effects analysis
-2.92
0
2.92
9