© International Epidemiological Association 1999
International Journal of Epidemiology 1999;28:865–873
Printed in Great Britain
Airway diseases and allergies in East and
West German children during the first
5 years after reunification: time trends
and the impact of sulphur dioxide and
total suspended particles
Ursula Krämer,a,c Heidrun Behrendt,b Reinhard Dolgner,a Ulrich Ranft,a Johannes Ring,c
Heidemarie Willerd,e and Hans-Werner Schlipkötera
Background East-West comparison studies in Europe find higher prevalences of infectious
airway diseases and lower prevalences of allergies in eastern areas. Pollution from
sulphur dioxide (SO2) or total suspended particles (TSP) are discussed as causes
of this difference.
Methods
In four differently polluted areas of East Germany where pollution decreased
dramatically between 1989 and 1995 cross-sectional studies in about 7-year-old
children were repeated every year between 1991 and 1995. In two differently
polluted areas of West Germany studies with the same design were done in 1991
and 1994. In all, 19 090 children participated in the study. Thirteen different
questions about airway diseases and allergies were evaluated. Logistic regression
was used to adjust for confounding.
Results
With the exception of pneumonia, all infectious airway diseases and irritations of
the airways show a steeper temporal decrease in East than in West Germany or
are positively associated with either SO2 or TSP in East Germany. For allergies
and related symptoms no differences in time trends could be detected or
no association with SO2 or TSP could be seen in East Germany.
Conclusion
Most airway diseases were more frequent in East than in West Germany in 1991
and were associated with SO2 or TSP. The decrease in these pollutants between
1991 and 1995 has already had a favourable effect. An effect of SO2 or TSP
pollution on allergies and related symptoms could not be detected. This pollution
does not protect against the development of allergies.
Keywords
Allergy, child, West Germany, East Germany, respiration disorders, sulphur dioxide,
total suspended particles
Accepted
10 March 1999
After the political changes in eastern Europe several research
groups studied the prevalences of airway diseases and allergies
in areas of eastern and western Europe.1–6 According to these
a Medical Institute of Environmental Hygiene, Düsseldorf, Germany.
b Division of Environmental Dermatology and Allergology GSF- National
Research Center for Environment and Health/ Technical University
München, Germany.
c Department of Dermatology and Allergology—Am Biederstein, München,
Germany.
d Institute of Hygiene Saxony-Anhalt, Magdeburg, Germany.
e Ministry of Social Affairs Saxony-Anhalt, Magdeburg, Germany.
studies, allergic diseases and sensitizations were more prevalent
in the western areas whereas infectious airway diseases and
irritations were more prevalent in the eastern ones. Generally,
higher disease prevalences in the eastern areas are explained by
the higher sulphur dioxide (SO2) and total suspended particles
(TSP) pollution in these areas. Some even suggest that the
prevalence of allergies is lower in the eastern areas because the
eastern type of pollution helps protect against the development
of allergies.7 However, in most of these studies only one
location in the east and the west were compared at a maximum
of two time points after the political changes, therefore we do
not think this conclusion convincing. Environment and lifestyle
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
differ in many respects between eastern and western areas. If
this conclusion is valid then—parallel to the steep decrease
in SO2 and TSP pollution in East Germany but not in West
Germany—airway diseases should show a steeper decrease
and allergies a steeper increase in East than in West Germany.
Furthermore airway diseases should show a negative, and allergies a positive, association with SO2 and TSP when restricting
the analysis to differently polluted areas in East Germany alone.
Chronic exposure to high levels of SO2 and particulate matter
(PM) has already been associated with higher prevalences of
respiratory illness and symptoms in children since the 1970s.8–17
Whether chronic exposures to SO2 and PM can modify the
prevalence of allergies is not yet decided. There is experimental
evidence for enhanced sensitization among guinea pigs after
exposure to SO2.18 Human experimental studies show an
increased airway response in asthmatics.19 Sulphur-related
pollution has an adverse effect on bronchial responsiveness.20
The association of PM with prevalent symptoms of the airways
is stronger in asthmatic than in non-asthmatic children,21 and
the aggravation of asthma symptoms on days with higher air
pollution levels than the day before is well known.22,23
The results presented here come from the only East-West
comparison study run in differently polluted areas in East as
well as in West Germany during the first five years after the
reunification. This study was designed to monitor the temporal
changes in prevalence rates of airway diseases and allergies in
East Germany relative to those in West Germany, and to detect
the impact of SO2 and TSP by investigating differently polluted
areas in East Germany. We assessed airway diseases and allergies by parental questionnaires in yearly surveys of 7-year-old
children. Results from routine measurements were used to
characterize air pollution in the different study areas and years.
Materials and Methods
Study population and areas
All boys and girls living in geographically defined areas and of
school entry age were chosen to participate in the study. The
single rounds of this study took place immediately after the school
entrance examination compulsory for all school beginners. The
study was conducted between February and May of the pertinent years. All study areas lay in a plain at about 60 m above sea
level and at about the same geographical latitude.
The East German study areas were selected to represent a
broad range of SO2 and PM ambient air concentrations: Leipzig
(inhabitants: 508 000) and Halle (inhabitants: 307 000) are
industrialized cities with intense pollution, Magdeburg (inhabitants: 277 000) was moderately polluted, and Altmark is a rural
region north of Magdeburg. Here, study centres were the four
small district capitals Salzwedel (23 000 inhabitants), Osterburg
(,20 000 inhabitants), Gardelegen (,20 000 inhabitants), and
Klötze (,20 000 inhabitants). In all East German areas crosssectional studies were conducted each year. Compared to the
other years, the study areas in Halle, Magdeburg, and Salzwedel
were extended in 1991 and 1994.
In West German Duisburg (537 000 inhabitants), an industrialized town in the Ruhr District, studies took place in 1991
and 1994. In 1991, nearly the whole city was covered, whereas
in 1994 the study was restricted to two areas in the northern
and southern part of the city. Borken (36 000 inhabitants) is a
small district capital, north of the Ruhr District. Children from
Borken were studied in 1991, 1993, and 1994.
The study was approved by the ethical committee of the
Landesärztekammer Saxony-Anhalt.
Health effect variables and covariates
A questionnaire was sent to the parents along with a letter of
invitation from the local health departments. It was to be
completed at home and checked by a physician on the day of
investigation.
Six different questions on infectious respiratory diseases and
irritations were included and analysed: pneumonia ever
diagnosed by a physician (pneumonia), bronchitis ever diagnosed by a physician (bronchitis), number of colds during the
last 12 months (>5 colds), tonsillitis during the last 12 months
(tonsillitis), dry cough during the last 12 months (dry cough),
frequent cough in the morning or during the day without a cold
(frequent cough). Seven questions on allergic manifestations
and symptoms were analysed: bronchial asthma ever diagnosed
by a physician (bronchial asthma), hay fever ever diagnosed by
a physician (hay fever), eczema ever diagnosed by a physician
(eczema), allergy ever diagnosed by a physician (allergy), reddened or itching eyes often during the last 12 months (irritated
eyes), sneezing or running or stuffy nose often during the last
12 months without a cold (irritated nose), wheezing ever (not
asked in 1992 and 1993) (wheezing). A German translation of
ISAAC-questions24 was used for assessing symptoms of allergies.
The following variables were included in the analysis as
potential confounders: gender, education of parents (highest
level of either parent; cutoff point: ‘class 10 finished’), bedroom
sharing (number of additional persons sleeping in the child’s
bedroom), heating with fossil fuels in the child’s home, use of
unvented gas cooker in the child’s home, dampness of the child’s
home, actual smoking in the child’s home, and/or maternal
smoking during pregnancy.
Air pollution measurements
Measurement values from one to three fixed stations run by
state institutions in each investigation area were used to
calculate yearly means of SO2 and TSP. For the Altmark area
values gained in Stendal, the biggest town in the Altmark and
in Salzwedel were available. Only those stations were taken into
consideration where the same automatic measurement procedures were used. The TSP were sampled with a low-volume
sampler (air flow = 1 m3/hour) and analysed radiometrically.
The concentrations of SO2 were analysed conductometrically.
The mean values of the 2 years preceding the investigation were
taken as exposure variables.
Statistical analysis
Logistic regression was used to determine (a) adjusted differences in time trends between East and West Germany and (b)
adjusted SO2 and TSP effects in East Germany alone. The parameter estimates were transformed to odds ratios (OR).
Adjusted differences in time trends were estimated by including an East/West (EW) variable (East = 1, West = 0), a time (T)
variable (1995 = 0, 1994 = 0.25,..., 1991 = 1), and an interaction
AIRWAY DISEASES AND ALLERGIES IN EAST AND WEST GERMANY
term EW * T additionally to the covariates into the model.
With the given coding an OR greater than one for the interaction means that the decrease over time in East Germany is
steeper than in West Germany. If the interaction was not
significant, the analysis was repeated without inclusion of the
interaction term, and one OR for the East-West effect is given.
If the interaction was significant the analysis was repeated for
values from 1991 and from 1994 separately, and the OR are
given for both years.
Adjusted SO2 and TSP effects were estimated simultaneously
by including the area-specific and year-specific 2-year concentrations additionally to the covariates into a logistic regression
model. We scaled the regression coefficients roughly to the
range of the area-specific and time-specific mean values of
the air pollutants (SO2: 200 µg/m3/TSP: 50 µg/m3). Because of
the high correlation of the TSP variable with time (Pearson
correlation: r = 0.89), inclusion of time could mean overadjusting the TSP effect. Therefore results are given with and without
inclusion of time.
After a specification test,25 living in an urban or a rural place
was additionally included into the models. Living in an urban
or rural place proved to have a strong effect on most target
variables even after inclusion of all covariates and exposure
variables. No additional unexplained variance between areas
and years could be detected.
867
Results
Participation and raw prevalences
In all, 19 090 children participated in the investigation (average
response = 87%). The values in the single years and areas are
given in Table 1.
Children who resided for less than 2 years in the area of
interest, children not of German nationality, and not in the predefined age range (5–8 years) were excluded from the analysis.
Thus, 15 850 were included. The regression analysis was
based on those 14 144 children for whom information on all
covariates was available.
The prevalences of confounding and target variables varied
considerably between areas and years. The area-specific and
year-specific values are given in Tables 2–4.
Differences in time trends between
East and West Germany
Adjusted OR describing the East-West differences are listed
in Table 5. Four of the six infectious airway diseases showed
time * East-West interactions significantly greater than one,
thus characterizing a steeper decrease in East than in West
Germany over time. In the case of a significant interaction the
East-West OR are given for 1991 and 1994 separately. In 1991,
these OR were greater than one, and in most cases significantly
Table 1 Description of the exposure variables sulphur dioxide (SO2) and total suspended particles (TSP) averaged over the 2 years preceding the
investigation, SO2 in children’s birth year additionally, and the study sample characteristics by area and year
Area
Leipzig (East)
Halle (East)
Magdeburg (East)
Year of
investigation
SO2
(µg/m3)
SO2 in
birth year
(µg/m3)
TSP
(µg/m3)
No. of
children
investigated
Response
(%)
German
nationality
(%)
Living ,2 years in
the respective area
(%)
1991
240
405
79
571
96
99.3
9.2
1992
164
320
79
562
94
100
6.5
1993
136
280
75
263
88
100
6.6
1994
102
270
62
336
65
99.7
8.0
1995
76
295
53
412
88
99.5
7.8
1991
201
302
102
1240
89
99.7
8.5
1992
143
281
73
391
93
99.7
7.4
1993
102
268
62
428
98
99.8
5.1
1994
73
227
52
1656
83
99.8
8.3
1995
63
209
46
399
93
100
5.1
1991
67
100
85
1333
94
99.9
10.4
1992
70
112
75
366
92
99.5
9.1
1993
72
100
69
312
79
100
9.2
1994
67
65
58
1435
67
98.7
10.2
59
1995
54
52
296
64
98.3
11.3
1991
68
70
929
96
99.8
4.2
1992
57
70
952
96
99.8
3.7
1993
52
67
896
95
99.7
5.6
1994
45
61
918
94
99.5
7.6
1995
54
47
762
90
99.6
9.4
Duisburg (West)
1991
33
64
66
3180
76
78.4
8.9
1994
28
45
56
373
72
63.3
8.3
Borken (West)
1991
18
56
383
93
96.6
7.7
1993
20
55
403
93
95.3
8.2
1994
18
52
294
93
92.8
8.2
Altmark (East)
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
Table 2 Description of covariates by area and year, German children (5–8 years) living at least 2 years in the respective area
Year of
Area
investigation
Leipzig (East)
1991
1992
1993
1994
1995
Halle (East)
1991
1992
1993
1994
1995
Magdeburg (East)
1991
1992
1993
1994
1995
Altmark (East)
1991
1992
1993
1994
1995
Duisburg (West)
1991
1994
Borken (West)
1991
1993
1994
Parents’
education
<10 form
(%)
57.1
53.2
54.8
53.9
53.4
43.9
48.5
49.0
46.6
45.5
44.4
43.0
48.0
47.4
40.7
55.1
57.1
54.9
60.1
55.4
67.0
55.8
50.5
48.0
44.9
Bedroom
sharing
(arithmetic
mean)
0.75
0.74
0.70
0.80
0.65
0.70
0.77
0.64
0.61
0.62
0.75
0.70
0.68
0.59
0.57
0.75
0.62
0.64
0.60
0.67
0.76
0.66
0.51
0.51
0.45
Heating with
fossil fuels
(%)
92.7
91.7
82.1
81.6
71.8
49.6
73.5
64.8
29.8
56.0
43.1
53.1
43.3
37.2
37.7
46.5
41.7
34.8
37.9
31.3
17.5
15.4
11.6
12.2
14.8
Use of
unventilated
gas cooker
(%)
78.8
76.3
71.6
77.3
68.7
44.7
66.9
54.9
31.5
50.0
46.1
57.7
55.0
45.1
50.6
43.4
35.1
32.6
32.7
27.9
1.7
1.4
2.4
2.8
4.8
Dampness
of flat
(%)
20.0
20.7
27.8
29.4
23.5
10.3
13.4
15.2
9.5
15.2
5.9
9.0
11.6
11.4
10.4
8.1
5.2
5.6
10.5
9.1
6.3
6.0
3.5
1.7
2.0
Passive
smoking
(%)
57.5
55.9
52.9
59.1
46.3
51.6
51.8
54.2
47.6
48.2
47.6
49.8
47.2
46.1
46.0
49.0
46.0
48.2
47.7
43.5
71.8
61.8
53.1
48.0
52.6
Table 3 Description of health effect variables: infectious airway diseases and irritations of the airways, raw percentages by area and year, German
children (5–8 years) living at least 2 years in the respective area
Year of
investigation
1991
1992
1993
1994
1995
Halle (East)
1991
1992
1993
1994
1995
Magdeburg (East)
1991
1992
1993
1994
1995
Altmark (East)
1991
1992
1993
1994
1995
Duisburg (West)
1991
1994
Borken (West)
1991
1993
1994
Area
Leipzig (East)
Pneumoniaa
8.9
8.9
12.4
8.9
10.3
14.1
14.6
12.2
13.3
17.8
11.7
6.2
5.5
9.0
5.7
14.8
17.1
12.8
13.5
14.3
9.0
8.3
8.4
11.6
10.8
a Ever diagnosed; b In the last 12 months; c Ever.
Bronchitisa
51.7
50.1
52.0
53.3
46.0
60.5
54.7
49.6
50.4
51.9
58.8
46.9
47.6
52.6
44.3
51.1
47.1
44.2
47.5
39.2
44.7
57.7
43.0
50.6
53.0
>5 coldsb
24.5
19.6
19.5
18.9
12.4
18.5
16.6
13.9
13.0
10.2
15.8
16.6
10.3
15.2
11.6
9.0
9.9
9.0
8.4
7.1
15.2
12.9
10.3
13.1
8.9
Tonsillitisb
38.0
37.1
31.4
31.3
24.8
23.6
23.9
20.0
17.5
20.8
23.3
25.0
21.3
25.5
18.3
17.9
19.1
21.9
22.3
18.1
25.0
23.0
11.5
22.4
17.7
Dry coughb
26.2
16.9
23.0
19.7
15.3
21.2
21.3
20.0
17.4
19.9
20.2
14.6
11.2
15.2
13.2
11.1
9.8
8.6
8.6
10.6
16.5
25.8
13.6
15.7
19.7
Frequent coughc
17.9
7.8
15.2
10.0
7.0
11.6
12.8
9.9
6.4
9.5
8.1
5.8
2.5
6.0
7.6
6.0
4.2
3.3
3.7
3.8
9.0
9.2
5.0
5.9
4.8
AIRWAY DISEASES AND ALLERGIES IN EAST AND WEST GERMANY
869
Table 4 Description of health effect variables: allergic diseases and symptoms, raw percentages by area and year, German children (5–8 years)
living at least 2 years in the respective area
Area
Leipzig (East)
Year of
investigation
Irritatedb
eyes
Irritatedb
nose
Wheezingc
14.2
Bronchiala
asthma
Hay fevera
Eczemaa
Allergya
12.1
1991
6.1
25.1
2.2
1.0
13.1
1992
1.7
15.8
2.7
0.2
10.5
7.8
1993
4.0
24.5
5.0
2.3
13.0
11.3
1994
4.8
22.0
17.2
2.8
1.0
11.6
8.5
1995
2.5
9.8
16.7
2.6
2.3
11.7
6.2
1991
7.4
19.2
17.8
2.1
1.3
15.2
9.5
1992
5.9
18.8
3.2
1.0
12.7
7.6
1993
2.9
13.6
1.9
1.1
12.6
9.6
1994
3.6
13.7
19.3
2.3
1.9
14.8
7.8
1995
6.7
14.9
20.1
2.9
2.0
17.7
9.9
1991
5.3
21.0
19.8
1.4
1.6
15.1
12.0
1992
4.7
12.8
0.9
0.9
12.3
8.6
1993
2.2
10.5
1.5
0.4
14.7
7.8
1994
5.3
12.2
16.8
1.8
2.2
17.1
8.3
1995
2.0
9.6
12.0
0.8
1.6
15.8
8.2
1991
3.7
10.7
14.3
1.1
1.2
14.4
13.4
1992
1.5
6.9
0.4
0.4
10.2
7.6
1993
2.2
8.3
1.3
0.9
14.3
8.9
1994
2.2
9.1
14.0
1.8
0.7
13.6
5.8
1995
3.1
8.8
12.8
1.9
0.8
15.8
6.7
Duisburg (West)
1991
4.6
15.3
16.0
2.5
2.4
10.4
15.6
1994
5.6
13.8
24.4
4.2
5.1
20.4
14.4
Borken (West)
1991
3.9
10.0
38.2
1.8
1.5
10.3
17.9
1993
3.7
6.5
0.9
1.1
8.8
15.8
1994
3.2
4.4
2.8
2.4
14.0
12.1
Halle (East)
Magdeburg (East)
Altmark (East)
18.7
a Ever diagnosed; b In the last 12 months; c Ever, not asked in 1992 and 1993.
so. None of the allergic diseases and symptoms showed a time
trend significantly different between West and East Germany.
Therefore, the global OR are presented. These were significantly
lower than one for bronchial asthma, hay fever, allergy, and
wheezing. For eczema and irritated nose, the OR were
significantly greater than one.
Association with mean SO2 and TSP levels
in East Germany
The 2-year average concentrations of SO2 varied between 240
µg/m3 and 45 µg/m3, the respective values for TSP lay between
102 µg/m3 and 46 µg/m3 (Τable 1). The steepest temporal
decline in SO2 values could be seen in Leipzig and Halle, the
cities with the highest values at the beginning of the study.
The SO2 concentration in the children’s birth years was about
twice that of the 2 years preceding the investigation. The spatial
differences in TSP were not as big as for SO2. Halle showed
the highest mean concentration before 1991 and the steepest
decrease. With this exception, the decrease in the East German
areas was quite similar. A comparatively very small decrease in
pollution values occurred in the western areas.
Table 6 lists the adjusted OR describing the association of the
frequencies of diseases and symptoms with the levels of SO2
and TSP. These two exposure variables were included simultaneously in the model. With the exception of pneumonia, all
infectious airway diseases and irritations of the airways showed
a significant association with SO2 or TSP. After adjusting for
time, all previously significant associations of SO2 and TSP with
infectious airway diseases and irritations of the airways remain
significant except for ‘>5 colds’ and TSP.
Of the allergies and related symptoms, bronchial asthma was
the only one showing a significant association with SO2. For
allergy, irritated eyes, and irritated nose, the OR characterizing
the relation to TSP were significantly greater than one before,
but not after correcting for time trend.
Figure 1 gives an overview for all results obtained.
Discussion
This study was designed to test whether SO2 and TSP pollution
can explain the higher prevalences of airway disease and the
lower prevalence of allergies observed in East Germany. If this
is the case then the time trends in the East should be different
from those in the West and such an association should be detectable in differently polluted areas from East Germany alone.
The data from this study show that with the exception of
pneumonia, all infectious airway diseases and irritations of the
airways show a steeper temporal decrease in East than in West
Germany or are positively associated with either SO 2 or TSP
in East Germany alone. No differences in time trends could be
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
Table 5 East-West differences in health effect variables, German children (5–8 years) from East and West German areas, 1991–1995,
living at least 2 years in the respective area, adjusteda global or time-specific odds ratios with 95% CI
Interaction
time * East/West
Odds ratio
East-West differences
1991
global
1994
Infectious airway diseases and irritations of the airways
Pneumonia ever diagnosed
Bronchitis ever diagnosed
>5 colds in last 12 months
Tonsillitis in last 12 months
Dry cough in last 12 months
Frequent cough ever
1.18
1.42
(0.75–1.86)
(1.22–1.65)
2.70
1.51
0.75
(2.04–3.57)
(1.33–1.71)
(0.61–0.93)
1.70
1.20
0.89
(1.12–2.58)
(1.01–1.43)
(0.64–1.25)
1.23
1.04
(0.88–1.73)
(0.93–1.16)
3.51
1.22
0.49
(2.46–5.01)
(1.03–1.44)
(0.38–0.64)
2.21
1.21
0.72
(1.29–3.77)
(0.98–1.50)
(0.47–1.10)
Allergic diseases and symptoms
Irritated eyes in last 12 months
Irritated nose in last 12 months
Wheezing ever
Bronchial asthma ever diagnosed
Hay fever ever diagnosed
Eczema ever diagnosed
Allergy ever diagnosed
1.33
1.04
(0.68–2.63)
(0.82–1.33)
0.69
1.25
(0.43–1.09)
(1.08–1.45)
0.78
0.66
(0.50–1.22)
(0.55–0.80)
0.97
0.66
(0.39–2.40)
(0.46–0.95)
0.99
0.49
(0.40–2.46)
(0.34–0.71)
1.44
1.22
(0.96–2.17)
(1.04–1.43)
1.28
0.63
(0.86–1.92)
(0.54–0.73)
a Adjusted for education, bedroom-sharing, heating with fossil fuels, use of unventilated gas cooker, dampness of flat, passive smoking, urban/rural living.
detected for allergies. Eczema, which was more prevalent in
East than in West Germany did not show a positive association
either to SO2 or to TSP whereas bronchial asthma, which was
less prevalent in East than in West Germany, did show a positive
association to SO2.
Association with SO2 and TSP
For the three smaller Altmark towns (Gardelegen, Klötze, and
Osterburg), data on SO2 and TSP were not available. This could
lead to an underestimation of the SO2 and TSP effects, and
may be one of the reasons for the significant urban/rural effect
remaining after inclusion of SO2 and TSP into the model. The
temporal and spatial variations in SO2 annual mean values in
East Germany during the time course of this investigation were
very high. The variations in TSP concentrations were comparatively small. Therefore, there is a greater possibility of detecting
SO2 effects than TSP effects. The results gained for infectious
airway diseases and irritations confirm the results from studies
conducted in the 1970s in western industrialized countries.8–17
There is an association of long-term high concentrations of SO2
in outdoor air with upper airway diseases and irritations, and an
association of long-term high concentrations of TSP with lower
airway diseases such as bronchitis. It is remarkable that in spite
of the huge differences in SO2 mean concentrations, bronchitis
seems to be associated with TSP only.
Odds ratios for the SO2 and TSP effects were smaller after
inclusion of an urban/rural factor. Because there could be many
differences between urban and rural areas which were not
accounted for in the analysis (different lifestyle, less traffic and,
therefore, less pollution), the parameter estimates after inclusion of the urban/rural factor are supposed to describe the underlying SO2 and TSP associations more correctly. The urban/rural
differences are discussed elsewhere in more detail.26 The year of
investigation is highly correlated with TSP concentrations. Thus,
including time into the statistical model yields less stable parameter estimates and may be an overcorrection. The significant
associations of the health effect variables with TSP seen before
including the time variable, vanish for allergy-related variables
AIRWAY DISEASES AND ALLERGIES IN EAST AND WEST GERMANY
871
Table 6 Influence of sulphur dioxide (SO2) and total suspended particles (TSP) on health effect variables, German children (5–8 years) from
East German areas, 1991–1995, living at least 2 years in the respective area, adjusteda odds ratios with 95% CI
Adjusted for time
trend additionally
SO2
per 200 µg/m3
TSP
per 50 µg/m3
SO2
per 200 µg/m3
TSP
per 50 µg/m3
Infectious airway diseases and irritations of the airways
Pneumonia ever diagnosed
1.17
1.06
1.17
0.96
(0.85–1.62)
(0.82–1.37)
(0.85–1.62)
(0.62–1.50)
Bronchitis ever diagnosed
0.84
1.63
0.85
1.39
(0.68–1.04)
(1.37–1.93)
(0.68–1.05)
(1.03–1.87)
>5 colds in the last 12 months
1.56
1.29
1.55
0.94
(1.18–2.05)
(1.03–1.63)
(1.18–2.04)
(0.63–1.41)
Tonsillitis in the last 12 months
1.89
0.95
1.89
0.97
(1.49–2.39)
(0.78–1.15)
(1.49–2.39)
(0.69–1.35)
Dry cough in the last 12 months
1.48
1.08
1.46
0.74
(1.13–1.94)
(0.87–1.36)
(1.12–1.91)
(0.50–1.09)
Frequent cough ever
2.64
1.04
2.51
0.60
(1.86–3.74)
(0.77–1.41)
(1.79–3.53)
(0.36–0.98)
Allergic diseases and symptoms
Irritated eyes in the last 12 months
1.05
1.67
1.06
1.40
(0.66–1.70)
(1.13–2.47)
(0.66–1.70)
(0.69–2.82)
Irritated nose in the last 12 months
1.27
1.51
1.26
1.03
(0.96–1.68)
(1.20–1.91)
(0.96–1.66)
(0.69–1.53)
Wheezing ever
0.71
1.14
0.68
0.92
(0.48–1.05)
(0.80–1.61)
(0.46–1.01)
(0.51–1.66)
Bronchial asthma ever diagnosed
2.46
0.57
2.73
1.31
(1.18–5.15)
(0.30–1.06)
(1.24–6.04)
(0.46–3.75)
Hay fever ever diagnosed
0.60
0.76
0.60
0.69
(0.23–1.52)
(0.38–1.55)
(0.24–1.52)
(0.17–2.91)
Eczema ever diagnosed
0.87
0.97
0.87
0.98
(0.65–1.18)
(0.77–1.23)
(0.65–1.18)
(0.64–1.51)
Allergy ever diagnosed
0.88
1.63
0.93
0.54
(0.62–1.25)
(1.23–2.15)
(0.67–1.29)
(0.33–0.89)
a Adjusted for education, bedroom-sharing, heating with fossil fuels, use of unventilated gas cooker, dampness of flat, passive smoking, urban/rural living.
but not for bronchitis. Therefore, the positive association before
including time is due to a common trend over time and might
not reflect a causal relation. Compared to other studies17,18
where the pollution with SO2 and TSP has been judged separately and where no measures were taken to account for
possible residual confounding by place or time the parameter
estimates given in Table 6 may underestimate the SO2 and TSP
effect.
The association of SO2 with bronchial asthma is due to spatial
differences in the prevalence of this health outcome variable
which are similar to the spatial differences in SO2 concentration
in 1991. Time series studies show that asthmatic symptoms are
related to high SO2 values.23 Possibly, the presence of asthma is
more easily detected in regions where high SO2 values occur
often. The steep temporal decrease in the SO2 values is not
reflected by a trend in the prevalence of asthma (Τable 4). Our
results could be explained if early exposure is necessary for the
development of the disease. All children investigated in this
study were born before the reunification.
East-West differences, time trends and the relative
impact of SO2 and TSP
The results of this study as to frequency differences in respiratory and allergic diseases between West and East Germany just
after the reunification (1991) are consistent with all other reports
describing differences in prevalences between one eastern and
one western site.1,3,4 The higher prevalences of infectious
respiratory diseases and irritations of the airways in the eastern
areas were explained by the higher SO2 and TSP pollution in
these areas. According to the data presented here, this was
confirmed for bronchitis, the number of colds, dry cough, and
frequent cough. All of these showed a downward trend in the
East which is different from the trend in the West. The East/
West differences in infectious airway diseases and irritations of
the airways observed in 1994 obviously cannot be explained by
the differences in SO2 and TSP pollution any more. This is similar to the results of a recent study,20 which observed the effects
of an air quality intervention in Hong Kong, which reduced SO2
pollution similarly to that observed in East Germany after the
872
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
Figure 1 East-West differences and associations of sulphur dioxide (SO2) and total
suspended particles (TSP) in East Germany with infectious airway diseases and irritations
of the airways, and allergic diseases and symptoms, 1991–1995. Seven-year-old German
children living at least two years in the study areas (East: Leipzig, Halle, Magdeburg,
Altmark; West: Duisburg, Borken). Odds ratios with 95% CI adjusted for socio-demographic
factors, indoor air quality, urban/rural living, and time trend (time trend not for yearspecific odds ratios)
reunification. The authors could show an improvement in
bronchial responsiveness in the first year after the intervention
leading to similar values for the polluted and the control
regions. After that no further improvement could be observed
in spite of still higher SO2 values in the polluted region. We do
not have an explanation for the increase of bronchitis and dry
cough in West Germany (Τable 3).
A higher prevalence of a certain symptom or illness in the
East over the West does not necessarily mean that SO2 and TSP
are related to that endpoint. Pneumonia and eczema, for instance, are more frequent in the East than in the West, but they
do not exhibit differences in time trends, or an association with
SO2 or TSP. Unmeasured factors like differences in disease labelling might be given as an explanation. However, since dermatologists in the field also saw more atopic eczema in East than in
West Germany when diagnosing this illness in a standardized
way,27 disease labelling cannot, in the case of eczema, explain
the observed effect.
We conclude that most airway diseases and symptoms having
been more frequent in East than in West Germany in 1991,
indeed are associated with SO2 or TSP, and the decrease in
SO2 and TSP pollution between 1991 and 1995 already had a
AIRWAY DISEASES AND ALLERGIES IN EAST AND WEST GERMANY
favourable effect on the prevalence of these diseases. A favourable effect of SO2 and TSP pollution on allergies could not be
detected.
873
12 Spinaci S, Arossa W, Bugiani M, Natale P, Bucca C, de Candussio G.
The effects of air pollution on the respiratory health of children:
a cross-sectional study. Pediatr Pulmonol 1985;1:262–66.
13 Dodge R, Solomon P, Moyers J, Hayes C. A longitudinal study of
Acknowledgements
The study was supported by the Ministry of Environment,
Northrhine-Westphalia (West Germany), and the Ministry of
Social Affairs, Saxony-Anhalt (East Germany). The authors
thank the staff of the local health departments for organizing
the study, and Mrs Konrad for typing the manuscript.
children exposed to sulfur oxides. Am J Epidemiol 1985;121:720–36.
14 Kerrebijn KF, Mourmans RM. Study on the relationship of air
pollution to respiratory disease in schoolchildren. Environ Res 1975;
10:14–28.
15 Bates DV. Adverse health impacts of air pollution—continuing
problems. Scand J Work Environ Health 1995;21:405–11.
16 Dockery DW, Speizer FE, Stram DO, Ware JH, Spengler JD, Ferris BG.
Effects of inhalable particles on respiratory health of children. Am Rev
Respir Dis 1989;139:587–94.
17 Ware JH, Ferris BG, Dockery DW, Spengler JD, Stram DO, Speizer FE.
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