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Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children’s asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, is a cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012. The questionnaire included the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3–6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. The analyses for the results showed that: (1) There is no obvious association between the diseases and ambient PM10 concentration; (2) The association between the diseases and economic status indexed by GDP (Gross Domestic Production) per capita needs further study; (3) Prevalences are higher in humid climates with hot summers and cold winters but do not have centrally heated buildings.
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SPECIAL TOPIC doi: 10.1007/s11434-013-5914-z
China, Children, Homes, Health
Ten cities cross-sectional questionnaire survey of children asthma
and other allergies in China
ZHANG YinPing1*, LI BaiZhan2*, HUANG Chen3, YANG Xu4, QIAN Hua5, DENG QiHong6,
ZHAO ZhuoHui7, LI AnGui8, ZHAO JiaNing9, ZHANG Xin10, QU Fang1, HU Yu3, YANG Qin2,
WANG Juan2, ZHANG Ming4, WANG Fang9, ZHENG XiaoHong5, LU Chan6, LIU ZhiJian8,
SUN YueXia11, MO JinHan1, ZHAO YiLi5, LIU Wei3, WANG TingTing12, NORBÄCK Dan13,
BORNEHAG Carl-Gustaf14 & SUNDELL Jan1*
1 Department of Building Science, Tsinghua University, Beijing 100084, China;
2 Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment, Chongqing University, Chongqing 400030, China;
3 School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China;
4 College of Life Sciences, Central China Normal University, Wuhan 430079, China;
5 School of Energy & Environment, Southeast University, Nanjing 210096, China;
6 School of Energy Science and Engineering, Central South University, Changsha 410083, China;
7 School of Public Health, Fudan University, Shanghai 200032, China;
8 School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;
9 School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;
10 Research Center for Environmental Science and Engineering, Shanxi University, Taiyuan 030006, China;
11 School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China;
12 School of Public Health, Xinjiang Medical University, Urumqi 830011, China;
13 Department of Occupational and Environmental Medicine, University Hospital and Uppsala University, Uppsala SE-751, Sweden;
14 Public Health Sciences, Karlstad University, SP Technical Research Institute of Sweden, Uppsala SE-751, Sweden
Received February 20, 2013; accepted May 15, 2013
Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially
among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic
change in indoor environmental exposures during the past two decades. However, such changes and their associations with chil-
dren’s asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, is a
cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012. The questionnaire
included the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions
regarding housing, life habits and outdoor environment. In health analyses, children aged 3–6 years old were included. The preva-
lences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in
2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and
4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheeze-
where the highest value was for Urumqi. The analyses for the results showed that: (1) There is no obvious association between the
diseases and ambient PM10 concentration; (2) The association between the diseases and economic status indexed by GDP (Gross
Domestic Production) per capita needs further study; (3) Prevalences are higher in humid climates with hot summers and cold
winters but do not have centrally heated buildings.
environmental health, indoor air quality, homes, exposure, urbanization
Citation: Zhang Y P, Li B Z, Huang C, et al. Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China. Chin Sci Bull,
doi: 10.1007/s11434-013-5914-z
2 Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1
Asthma prevalence has increased worldwide during the last
decades [1–7]. The magnitude of prevalence has generally
been smaller in low-income countries or regions, but the
rates of increase may be accelerating [1,4,5]. The Interna-
tional Study of Asthma and Allergies in Childhood (ISAAC)
reported that the highest prevalences of asthma in children
aged 6–7 years were in the UK, Australia, New Zealand and
Ireland, while the lowest prevalences were in Indonesia,
Albania, Romania, Georgia and Greece [1]. In many parts
of the world, a large fraction of children have or have had
asthma, wheeze, rhinitis or eczema [1,2]. The cost, family
burden and impaired life quality due to asthma and allergies
are severe public health problems. It is anticipated that there
will be about 300 million people suffering from asthma by
2025 [6].
Neither genetic factors [7], outdoor environmental pollu-
tion [8–12], racial factors [13], nor socio-economic status
[14] can wholly explain this dramatic increase. People
spend a large part of their time indoors and pre-school chil-
dren spend a longer time in homes compared with adults
[15,16]. The indoor environment, especially in homes, has
been implicated as having an important role in inducing
and/or exacerbating asthma and allergies among children
The ISAAC project was started in 1990 in Germany and
New Zealand with the aim of quantifying the prevalence
and characterizing the severity of asthma and allergies
worldwide [26]. Studies had been conducted in 236 centers
in 98 countries [27] before 2009. However, ISAAC studies
lack data on indoor environmental and building related risk
factors. The idea to study “asthma and the home environ-
ment” was initiated in Sweden because of the Allergy In-
quiry (a 1987–1989 governmental inquiry) to identify caus-
es of the dramatic increase of allergic children in Sweden.
The Swedish study, “Dampness in Buildings and Health”
(DBH) was started in 2000 with the aim of characterizing
associations between building dampness and asthma and
allergies among children. Its hypothesis and background
were based on scientific state-of-the-art reviews [17,28–33].
Questionnaires and experimental protocols were designed
for a multidisciplinary study involving environmental sci-
ence, engineering, chemistry and microbiology in addition
to medicine and public health. By 2010, studies built on the
platform of the Swedish study had been carried out in sev-
eral countries [19,22,34–38].
The prevalences of asthma and allergies have, in some
western countries, recently stabilized or even decreased
[39,40]. These changing trends coincide with the currently
slower rate of change in indoor environment exposures in
these countries. China, a developing country, is experienc-
ing rapid and dramatic changes in indoor environment ex-
posures due to its rapid modernization and urbanization.
National surveys of asthma in Chinese children aged 0–14
years in 1990 and 2000 by the Childhood Asthma Collabo-
rative Group of China [41] as well as a number of other
studies indicate that asthma and allergies have increased in
China [4,7,42–51]. However, information about indoor ex-
posure has been included to only a small extent and in only
a few studies [52,53].
In September 2010, we launched the project China, Chil-
dren, Homes, Health (CCHH) in 10 major cities in China.
Ten universities are involved in CCHH. There are two
phases: Phase I is a cross-sectional questionnaire study of
the prevalence of children’s asthma, allergies and airway
infections, and home environmental exposures (2010.11–
2012.4) (See Appendix A, Questionnaire for CCHH); Phase
II will be a case-control study with measurements of pollu-
tants in sampled air, dust and urine (2012.11–). The objec-
tives of the CCHH research project are:
(1) to investigate the prevalences of asthma, allergies and
airway infections in major Chinese cities with different cli-
mates, outdoor air quality, and economic level;
(2) to investigate and compare indoor environmental as-
pects of sick and healthy children’s homes;
(3) to study associations between children’s health and
indoor environmental factors;
(4) to compare risk and protective factors in different
cities of China;
(5) to compare findings from CCHH with those of other
countries and regions outside of mainland China;
(6) to provide epidemiological data as a foundation for
the prevention of asthma and allergies among children in
This paper reports some basic data from all cities and
some historic trends in the prevalences of asthma, allergies
and the percentage of children who have had one or more
episodes of pneumonia.
1 Subjects and methods
1.1 Sites studied and children selected
The CCHH study was carried out in 10 cities in different
geographic regions of China with different per capita eco-
nomic statuses and outdoor environmental pollution levels
(Table 1 and Figure 1). Every city included urban areas.
Some cities included rural or suburban areas. Kindergartens
or daycare centers or primary schools were randomly se-
lected in each city.
1.2 Questionnaire design and pilot study
CCHH research used questions from the ISAAC study [56]
about children’s asthma, and allergies. Questions from the
Swedish DBH study about the home environments [19]
were adapted so as to be relevant to Chinese home charac-
teristics [57]. The questionnaire was tested in a pilot study
of 100 children in Chongqing in April 2010, and thereafter
adjusted to improve readability. For details about question-
naire design, see articles for specific CCHH cities [58–68].
Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1 3
Table 1 Economic status, geography, climate and PM10 concentration of the investigated cities in CCHH studies
(from north to south)
Economic status
(Income, per capita GDP, kRMB)a) Dry/humid [54] Type of climate [55]
Annual mean concentration
of PM10 (μg/m3) b)
2001 2010
Harbin 37.0 Sub-humid Severe cold 134.7 102.6
Urumqi 44.9 Dry Severe cold 203.6 139.1
Beijing 75.9 Sub-humid Cold 175.2 122.3
Taiyuan 44.3 Sub-humid Cold 203.7 89.2
Xi’an 38.3 Sub-humid Cold 156.5 126.1
Nanjing 63.7 Humid Hot summer and cold winter 140.0 112.7
Shanghai 76.1 Humid Hot summer and cold winter 101.7 79.3
Wuhan 59.0 Humid Hot summer and cold winter 150.4 107.0
Chongqing 27.6 Humid Hot summer and cold winter 141.5 102.5
Changsha 66.4 Humid Hot summer and cold winter 181.0 83.6
a) From the annual report of each city, using 2010 data (except Taiyuan, 2009); b)from the Ministry of Environmental Protection of China.
Figure 1 Prevalences (%) of rhinitis, wheeze, and atopic eczema in the last 12 months and pneumonia (at least one episode), for children 3–6 years old in
all cities except Taiyuan (3–5) and Wuhan (5–6) years old.
1.3 Procedure for Phase I study
The procedure for the questionnaire survey was as follows:
We first contacted the director of each kindergarten. After
he or she agreed on participation, questionnaires were dis-
tributed by the responsible teachers in each class to the
children’s parents or legal guardians. Finally, parents re-
turned the questionnaires to the teachers, and we collected
the completed questionnaires from the teachers.
The data were input and statistically analyzed by SPSS
2 Results
In the CCHH investigation Phase I, parents of 48219 chil-
dren aged 1–8 responded to the questionnaire, yielding a
76.9% average response rate. Table 2 presents detailed in-
formation on children’s ages, numbers of respondents, and
response rates. Non-respondents were tracked by short
questionnaires in Chongqing. A number of 300 children
were randomly selected from those who had not responded
in the cross-sectional study and 206 responded. The five
4 Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1
Table 2 Number of respwondents and response rate in investigated cities
Cities Age
Number of
rate (%)
Harbin 2–8 2506 64.1
Urumqi 2–7 4618 81.7
Beijing 1–8 5876 65.0
Shanghai 1–8 15266 85.3
Nanjing 1–8 4014 65.7
Xi’an 1–8 2020 83.5
Taiyuan 1–6 3700 82.2
Wuhan 1–8 2193 91.4
Changsha 1–8 2727 59.0
Chongqing 1–8 5299 74.5
questions in the short questionnaires asked about home site
(location), gender, wheezing in the last 12 months, visible
damp stains and family smoking. There were no significant
differences between responses to the short questionnaire,
and responses to the same questions in the long question-
naire (see Table S1).
Distributions of gender, age and family allergic histories
among investigated children in 10 cities are shown in Table
3. As the number of children in age groups 1, 2, 7 and 8
were small in most cities, further analyses of health out-
comes were for children 3–6 years of age, except for Tai-
yuan (3–5 years of age) and Wuhan (5–6 years of age). Ta-
ble 4 shows the age-adjusted prevalences of illnesses (3–6
years, except Taiyuan (3–5) and Wuhan (5–6)). Prevalences
for the last 12 month of wheeze, rhinitis, and eczema, as well
as the percentages of children who had had one or more life-
time episodes of pneumonia, are shown in Figure 1.
Asthma was determined as a “yes” reply to the question
“Has your child ever been diagnosed with asthma by a doc-
tor?”. In Figure 2, the findings of the CCHH ten city study
in 2010–2011 are compared with mean prevalences among
0–14 year old children in 1990 and 2000 [41]. All preva-
lences are normalized against 1990 data. Figure 3 shows the
same comparison but with actual (non-normalized) data.
Prevalences of doctor-diagnosed asthma have increased
faster during the last ten years than during the decade from
1990 to 2000. Urumqi, Wuhan, Beijing and Shanghai had
the most rapid increase in the last decade.
Figures 4 and 5 show ecological comparisons. Southern
cities, humid all year but cold in winter and without heating,
Table 3 Percentages by gender, allergy in the family and children’s ages in CCHH Phase I citiesa)
City name Gender (%) Allergy in family (%) Age (%)
Male Female Yes 1 2 3 4 5 6 7 8
Harbin 50.3 49.7 13.3 0 1.8 10.3 21.2 23.0 27.3 14.4 2.0
Urumqi 53.6 46.4 19.8 0 2.1 24.3 36.0 30.4 6.9 0.1 0
Beijing 52.4 47.6 23.4 0.5 2.2 24.1 28.7 26.3 16.3 1.3 0.6
Shanghai 50.9 49.1 19.4 0.2 0.1 5.0 37.2 29.4 22.6 5.2 0.3
Nanjing 51.2 48.8 15.8 0.1 1.0 11.4 23.6 25.2 24.9 12.0 1.8
Xi’an 53.3 46.7 9.2 0.1 1.4 19.7 28.1 28.6 19.7 2.2 0.2
Taiyuan 52.3 47.7 11.5 0.2 4.5 30.4 36.4 26.8 1.7 0.0 0.0
Wuhan 52.7 47.3 16.9 0.5 0.1 1.4 3.6 4.8 10.3 32.2 47.1
Changsha 53.3 46.7 15.4 0.2 2.8 24.5 34.2 31.2 6.6 0.4 0.1
Chongqing 51.3 48.7 11.1 0.3 2.4 20.0 32.4 29.6 14.1 1.1 0.1
a) Age 1 means the children’s age 1, age 2 means the children’s age > 1 and 2, and so on.
Table 4 Age adjusted prevalences of symptoms and other illnesses in children 3–6 years old
Harbin Urumqi Beijing Shanghai
Nanjing Xi’an
Taiyuane) Wuhanf) Changsha
Wheeze ever 19.6 35.3 22.3 27.9 23.4 20.2
21.7 31.2 27.0 26.7
Wheeze last 12 months 15.3 23.7 16.7 21.6 17.9 13.9
14.1 19.0 19.3 20.2
Dry cough last 12 months 11.7 11.9 19.4 19.7 18.5 15.0
7.9 18.4 16.0 18.4
Dr.diagnosed asthma 2.9 3.9 6.3 9.8 8.8 3.0
1.7 7.4 6.9 8.2
Rhinitis ever 55.3 48.9 57.7 55.2 54.6 56.5
38.6 58.7 54.2 51.6
Rhinitis last 12 months 42.0 43.7 45.5 43.7 42.8 38.7
24.0 50.8 41.2 38.3
Rhinitis on pet exposure 1.0 4.3 3.3 4.6 2.0 2.1
2.5 9.3 2.0 2.7
Rhinitis on pollen/grass exposure 1.9 6.3 6.9 7.6 8.0 6.4
1.1 19.4 11.5 3.6
Dr. diagnosed Rhinitis 2.2 9.8 7.9 11.6 8.8 3.7
2.7 23.9 8.0 6.2
Eczema evera) 33.1 15.3 34.7 23.4 28.4 29.0
13.6 26.0 29.9 30.4
Eczema last 12 monthsb) 12.2 13.3 15.8 13.9 10.7 8.2
4.8 8.4 9.7 12.9
Croup 3.2 6.3 4.3 7.6 4.2 4.5
4.0 5.8 5.9 6.3
Pneumonia 30.2 41.7 26.9 33.2 27.1 28.2
27.8 25.5 38.1 31.3
Common cold 6 times last 12 months 6.0 7.6 9.5 8.5 9.9 7.1
4.7 6.1 7.9 18.1
Ear infectionc) 8.3 11.9 14.9 10.5 7.8 7.7
9.0 16.2 7.7 7.8
Food allergyd) 22.2 16.4 23.9 19.4 20.5 12.9
12.7 17.0 17.6 16.9
a) Has your child ever had an itchy rash (eczema), which was coming and going for at least 6 months? b) In the last 12 months, has your child had itchy
skin rash? c) Has your child ever had ear infections? d) Has your child ever developed itchy skin, rash, diarrhea, swollen lips, or swollen eyes as a result of
eating the foods below? e) Age adjusted for 3–5 years old children; f) Age adjusted for 5–6 years old children.
Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1 5
Figure 2 Prevalences of children’s asthma normalized for 1990.
have an asthma prevalence >6.9%. The dry northern cities
which do have heating during winter, have an asthma prev-
alence <4% with the exception of Beijing, with the asthma
prevalence of 6.3%. There are no associations in ecological
analyses between wheeze, rhinitis, eczema and pneumonia
and climate, GDP/capita or ambient PM10. From Table 1 it
is also seen that ambient PM10 is reported to have decreased
in all cities during the last 10 years, the years that asthma
has increased more rapidly. Figure 5 shows an association
between doctor-diagnosed asthma and GDP/capita, however
the result is distorted by the outlier Chongqing.
Data regarding general characteristics of the study popu-
lation, housing characteristics, and dampness, and odors in
homes are given in Tables S2–S4.
3 Discussion
The CCHH survey covers 10 major cities in China with
different climates, geographies and per capita economic
status. In total, there are 48219 children (and homes), of
whom 43591 are 3–6 years old, and included in the analyses
of health outcomes. The mean response rate, 76%, is rea-
sonably high. This study is subject to the limitations inher-
ent in any cross-sectional survey. Data used for analyses
were collected retrospectively and relied on parental reports;
our findings could therefore be subject to recall bias. How-
ever, the questions on outcomes were validated in the
ISAAC study[69], and questions on indoor exposures used
in the present study have been validated in previous stud-
ies[70,71]. Non-respondents were reached by a short survey
in Chongqing. There were no significant differences in the
prevalences of wheezing in the last 12 months between
responders and non-responders to the long questionnaire,
which indicates that neither selection nor non-response bi-
ases are likely present. The possible influence of bias on
Figure 3 National trends for children’s asthma in the cities investigated (3–6 years old, except for Taiyuan (3–5) and Wuhan (5–6) compared with the
prevalence of 0–14 years old children 1900, 2000 [41]).
6 Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1
Figure 4 Correlation between outdoor PM10 concentration in 2010 and
prevalence of asthma in 2011.
Figure 5 Correlation between GDP per capita in 2010 and prevalence of
asthma in 2011.
specific topics is discussed in the articles from each city
The prevalences of doctor-diagnosed asthma in CCHH
cities varied from 1.7% to 9.8% (mean 6.8%). This repre-
sents a great increase from 0.91% in 1999 (287329 children)
and 1.50% in 2000 (299193 children in 27 cities of China).
The prevalences of wheeze, rhinitis and eczema (last 12
month) varied from 13.9% to 23.7%, 24% to 50.8% and
4.8% to 15.8% respectively. For all symptoms, Taiyuan had
the lowest prevalences, whereas the more developed eastern
cities had the highest prevalences, with the exception of
Urumqi, which had the highest prevalence of wheeze. Eco-
logical analyses show no obvious association between dis-
eases and ambient air pollution (PM10), or the economic
status as indexed by GDP (Gross Domestic Production) per
capita, but suggest that prevalences were higher in humid
climates where summers are hot, winters cold, and there is
no heating. In comparison with earlier studies, the prevalenc-
es of parentally reported wheeze, rhinitis and eczema, and
parentally reported doctor-diagnosed asthma were high, indi-
cating increased prevalences of these symptoms and diseases.
Other recent studies [4,46–51] confirm these findings.
The comparisons in Figures 2 and 3 between prevalences
of doctor-diagnosed asthma in 1990, 2000 and 2011 are
important. Because the samples of children 1–2 and 7–8
years old were small, the present CCHH study reports
health outcomes for children 3–6 years old. The national
studies of 1990 and 2000 [41] surveyed children 0–14 years
old, so that a direct comparison is not possible. Nonetheless,
the CCHH survey of 10 cities shows that children’s asthma
has increased. Moreover, the increase has accelerated since
2000 (Figure 2).
The prevalences of wheeze, rhinitis and atopic eczema
are not as different between cities as the prevalences of
doctor-diagnosed asthma (Figures 1 and 3). The difference
in prevalences between parentally reported doctor-diag-
nosed asthma (Figure 3) and parentally reported symptoms
in different regions maybe due to regional differences in
health care systems. Comparison between Figure 1 (parental
reported wheeze) and Figure 3 (parental reported doctor-
diagnosed asthma) may reflect differences in how likely it is
that a child is taken to a clinic for a diagnosis of asthma as
well as for rhinitis.
The reported percentage of children who have had at
least one doctor-diagnosed episode of pneumonia is high
(25.5%–41.7%), especially given that urban pneumonia
rates are generally lower than those of rural areas, where
there is extensive exposure to smoke from burning of bio-
mass [72]. The children in this study are mainly living in
new modern apartments, exposed to environmental tobacco
smoke, indoor molds and dampness, with lower air ex-
change rate (see articles from Nanjing[65], and Urumqi [59]
for further discussion).
4 Conclusions
Prevalences of “allergic” diseases and symptoms have in-
creased in large Chinese cities. More than half of the 3–6
year old children surveyed have had at least one manifesta-
tion of wheeze, rhinitis or eczema, and more than one-fourth
of children have had at least one episode of pneumonia.
The changes in indoor environmental exposure caused by
the modernization of China may in part explain the increas-
ing prevalence of the studied diseases. Certainly, further
analyses and research (composition and size effect of PM,
e.q.) are necessary to unravel the riddles behind the rapid
increases. In Phase II, case-control studies in which pollu-
tants in air, dust and urine are measured, will be done. Na-
tion-wide collaborative research among inter-disciplinary
fields and groups will be needed.
This work was supported by the National Natural Science Foundation of
China (51136002, 51076079, 51006057), Ministry of Science and Tech-
nology of China (2012BAJ02B03) and National High Technology Research
and Development Program of China (2010AA064903). The authors are on
behalf of CCHH Phase I collaborative group. Sun YueXia and Mo JinHan
were the scientific secretaries for the papers. We also thank Zhang JP,
Wang H for their contribution in this study, and Louise B. Weschler for
careful revisions of the manuscript.
Zhang Y P, et al. Chin Sci Bull January (2013) Vol.58 No.1 7
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Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction
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Supporting Information
Table S1 Comparison between short questionnaires and Phase I questionnaires in Chongqing
Table S2 Summary of general characteristics of the study populations, children 1–8 years old (%)
Table S3 Summary of building characteristics in the investigated regions, children 1–8 years old (%)
Table S4 Dampness and odor indices in homes in the investigated regions, children 1–8 years old (%)
Table S5 Questionnaire used in CCHH Phase I
The supporting information is available online at and The supporting materials
are published as submitted, without typesetting or editing. The responsibility for scientific accuracy and content remains en-
tirely with the authors.
... This standard questionnaire has been validated by the pilot study and the Phase I of CCHH during 2010-2012. Our survey procedure followed methods in the Phase I of CCHH study Zhang et al. 2013). In brief, standard questionnaires were distributed to the children's caregivers (e.g., parents or grandparents) by the responsible teachers in the chosen kindergartens or daycare centers. ...
... Following systematic reviews about factors affecting childhood asthma (Hehua et al. 2017;Yan et al. 2020) and previous CCHH publications Zhang et al. 2013), we sorted out three sets of covariates in the regression analysis. These covariates included 1) children's individual characteristics: sex (boy [versus] vs. girl), birth season (spring vs. summer vs. autumn vs. winter), mode of delivery (cesarean vs. vaginal), preterm birth (<37 weeks, yes vs. no), low birth weight (<2500 g, yes vs. no) and ethnicity (Han vs. others); 2) parental variables: parental history of atopy (yes vs. no), duration of breastfeeding (<1 vs. 1-6 vs. 6-12 vs. ≥ 12 months), maternal smoking status (yes vs. no) and education attainment (senior high school or below vs. college vs. graduate school or higher); 3) household environment during early life: passive smoke exposure (yes vs. no), renovation (yes vs. no) and visible mould or damp (yes vs. no). ...
Full-text available
Background Emerging evidence suggests that early-life (in-utero and first-year since birth) exposure to ambient PM2.5 is a risk factor for asthma onset and exacerbation among children, while the hazards caused by PM2.5 compositions remain largely unknown. Objective To examine potential associations of early-life exposures to PM2.5 mass and its major chemical constituents with childhood asthma and wheezing. Methods By conducting the Phase II of the China, Children, Homes, Health study, we investigated 30,325 preschool children aged 3–6 years during 2019–2020 in mainland China. Early-life exposure to PM2.5 mass and its constituents (i.e., black carbon [BC], organic matter [OM], nitrate, ammonium, sulfate) were calculated based on monthly estimates at a 1 km × 1 km resolution from satellite-based models. We adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM2.5 constituents on childhood asthma/wheezing. Results The average PM2.5 concentrations during in-utero and the first year since birth were 64.7 ± 10.6 and 61.8 ± 10.5 µg/m³, respectively. Early-life exposures to a mixture of major PM2.5 constituents were significantly associated with increased risks of asthma and wheezing, while no evident compositions-wheezing associations were found in the first year. Each quintile increases in all five PM2.5 components exposures in utero was accordingly associated with an odds ratio of 1.18 [95% confidence interval: 1.07–1.29] for asthma and 1.08 [1.01–1.16] for wheezing. BC, OM and SO4²⁻ contributed more to risks of asthma and wheezing than the other PM2.5 constituents during early life, wherein the effects of BC were only observed during pregnancy. Sex subgroup analyses suggested stronger associations among girls of first-year exposures to PM2.5 components with childhood asthma. Conclusion Early-life exposures to ambient PM2.5, particularly compositions of BC, OM and SO4²⁻, are associated with an increased risk of childhood asthma.
... However, the rapid urbanization and industrialization in China have changed people's consumption patterns, lifestyles and living environments (9)(10)(11). Meanwhile, the prevalence of eczema in children has also increased rapidly (12). Studies have reported that eczema in children from specific regions may be associated with the residential (13)(14)(15)(16) and household environment (17)(18)(19). ...
... This study was based on a follow-up to the nationwide "China-Children-Homes-Health (CCHH)" study performed in 2010-2012 in multiple cities (12,25). A total of 4,700 questionnaires were distributed to 30 kindergartens to investigate allergies and infections among children during 2015-2016 in Shenzhen, China (Figure 1). ...
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Eczema, one of the most prevalent inflammatory skin diseases among children, is potentially influenced by genetic, environmental and social factors. However, few studies have investigated the effect of residential environment and lifestyle on childhood eczema. Therefore, this study conducted a cross-sectional study based on 2,781 preschool children in Shenzhen, China, during 2015–2016. Logistic regression models were employed to analyze the associations between residential/household environment, lifestyle, dietary habits and eczema in children. The prevalence of eczema among children in Shenzhen was 24.6%. Significant associations (increased odds >50%, P < 0.05) were found between childhood eczema and the factors of using composite wood floors (adjusted OR = 1.777 for doctor-diagnosed eczema, 1.911 for eczema-like symptoms), living in a villa/townhouse (aOR = 3.102, 2.156), the presence of mold or damp stains in the child's room (aOR = 1.807, 2.279), and rarely cleaning the child's room (aOR = 1.513, 1.540). In addition, watching TV/playing computer games for more than one hour per day was significantly associated with eczema (aOR = 1.172, 1.174). Notably, we found that eating rice/pasta one to three times per week may elevate the risk of eczema-like symptoms (aOR = 1.343), which warrants further investigation. In addition, ambient air pollution, in the covariates, may also affect childhood eczema. Therefore, avoiding these adverse factors and creating a low-risk environment are crucial to prevent childhood eczema.
Pollen is the main factor causing asthma and allergic rhinitis (AR). However, the key indoor and outdoor factors associated with childhood symptoms of allergic rhinitis (SAR) to pollen are unclear. We investigate the association of exposure to outdoor air pollution and indoor environmental factors with childhood SAR to pollen and consider SAR to pollen in different seasons. A cross-sectional study of 2598 preschool children aged 3–6 was conducted in Changsha, China (2011–2012). The prevalence of SAR to pollen in children and information on indoor environmental factors were obtained by questionnaire. Children’s exposure to outdoor air pollutants (PM10, SO2, and NO2) was estimated from the monitored concentrations. The association of exposure to indoor environmental factors and outdoor air pollution with childhood SAR to pollen was estimated by multiple logistic regression models using odds ratio (OR) and a 95% confidence interval (CI), and the relationship between outdoor air pollutants and childhood SAR to pollen was investigated using restricted cubic splines. We found that early-life and current exposure to outdoor air pollution were significantly associated with childhood SAR to pollen in autumn, including exposure to SO2 one year before conception (OR = 1.60, 95% CI = 1.08–2.37) and during entire pregnancy (OR = 1.49, 95% CI = 1.01–2.20) periods, exposure to PM10 during the current period (OR = 1.78, 95% CI = 1.07–2.96), and exposure to NO2 during the early-life (one year before conception and entire pregnancy) and current periods with ORs (95% CI) of 1.72 (1.10–2.71), 1.82 (1.17–2.83), and 1.94 (1.11–3.40), respectively. Further, we found significant associations of both prenatal and postnatal exposure to window condensation with childhood SAR to pollen, with ORs (95% CI) = 1.37 (1.05–1.77) and 1.38 (1.02–1.88), respectively. We encourage SAR to pollen sufferers to stay indoors due to outdoor air pollution and higher pollen concentration outdoors, but indoor ventilation should be maintained.
Background: Although studies have investigated the association between early-life exposure to fine particulate matter (PM2.5 ) and childhood asthma/wheezing, results are inconsistent and the susceptible exposure window remains largely unknown. Methods: A prospective birth cohort study was conducted to recruit pregnant women during their early pregnancy, and to follow up them and their children up to 3-4 years old. Diagnosis of asthma/wheezing was extracted from children's medical records. A spatiotemporal land-use regression (ST-LUR) model was used to assess maternal exposure to PM2.5 during pregnancy and their children's exposure after birth. The Cox proportional hazards model and accelerated failure time model (for violation of proportional hazards assumption) were applied to estimate the effects of prenatal and postnatal exposures to PM2.5 on the risk of childhood asthma/wheezing. Results: A total of 3725 children were included, and 392 children (10.52%) were diagnosed with asthma/wheezing. Both prenatal and postnatal exposures to PM2.5 were positively associated with the risk of asthma/wheezing. Each interquartile range (IQR) increment in PM2.5 exposure during the entire pregnancy (4.8 μg/m3 ) and the period from birth to the end of follow-up (1.5 μg/m3 ) was associated with adjusted hazard ratios (HRs) of 1.44 [95% confidence interval (CI): 1.13, 1.85] and 2.74 (95% CI: 2.59, 2.91), respectively. Subgroup analyses showed greater HRs for PM2.5 exposures during the pseudoglandular stage (6-16 gestational weeks [GWs]: IQR = 4.8 μg/m3 , HR = 1.10, 95% CI: 1.02, 1.18) and canalicular stage (16-24 GWs: IQR = 4.8 μg/m3 , HR = 1.13, 95% CI:1.03, 1.23) than other stages, and also showed significant effects in the first three-year period after birth (IQR = 1.5 μg/m3 , HR = 2.37, 95% CI: =2.24, 2.51). Conclusion: Higher prenatal and postnatal PM2.5 exposures may increase the risk of childhood asthma/wheezing. The pseudoglandular stage, canalicular stage, and the first three years after birth may be key susceptible to exposure windows.
Common cold is usually considered to be associated with outdoor climate, but the evidence linking with indoor environmental factors is lacking. The role of indoor renovations during which critical timing window on childhood common cold remains unclear. Therefore, we investigated the effect of exposure to new furniture and/or redecoration during prenatal and postnatal periods on the occurrence and duration of common cold in preschool children. We conducted a retrospective cohort study of 39 782 children aged 3–6 years in seven cities of China. The occurrence and duration of common cold in children, and their lifetime exposures to indoor new furniture and redecoration (including pregnancy, the first year of life, and after one year old) were assessed using a questionnaire administered by the parents. Associations between high frequency (>5 colds) and long duration (≥2 weeks per cold) of common cold during past 12 months and exposure to indoor new furniture/redecoration were examined by logistic regression models in terms of odds ratio (OR) and 95% confidence interval (CI). We found that the prevalence of high frequency and long duration of common cold in preschool children in China were, respectively, 9.2% and 11.9%. Frequent common cold was significantly associated with exposure to indoor new furniture/redecoration during pregnancy, first year, and after 1 year old, respectively, with the ORs (95% CI) = 1.25 (1.12–1.39), 1.11 (1.00–1.25), and 1.09 (1.01–1.18). Furthermore, childhood long duration per cold was associated with exposure to indoor new furniture/redecoration during pregnancy with OR (95% CI) of 1.14 (1.03–1.25) but not with postnatal exposure. We identified that prenatal exposure to home renovation was more critical than postnatal exposure for an increased risk of high frequency and long duration of common cold. Sensitivity analysis showed that the association between prenatal exposure to indoor renovations and the risk of childhood common cold was consistent and robust, and the associations were modified by some personal and indoor environmental factors. Our findings indicated that prenatal and postnatal exposure to home renovation played an important role in the risk of childhood common cold, supporting the hypothesis of “fetal origin of childhood infection.”
Little is known about the impact of socio-economic and environmental factors on the associations between PM2.5 exposure and health risk for elementary students. We estimated the space variability of effects of PM2.5 on daily illness-related absence rate for 2278 elementary schools from 97 counties across Jiangsu Province with data collected in the 2016-17 academic year. We evaluated the effects at school- and county-scales and examined the role of socio-economic and environmental factors with generalized addictive models (GAM). With an interquartile range (IQR, 32 μg/m³) increase in PM2.5 concentration, the relative risk of absence rate for a given school ranged between 1.00 and 2.81. Factors including high economic development level, low health expenditure, dense road network, dense population and low vegetation coverage drove strong effects for schools/counties. For the implementation of efficient clean air policies and public health interventions, we should concern about not only high-polluted areas but also areas under specific socio-economic and environmental conditions.
Background Increasing prevalence of childhood allergic rhinitis(AR) needs a deeper understanding on the potential adverse effects of early life exposure to air pollution. Objectives The main aim was to evaluate the effects of maternal exposure to PM2.5 and chemical constituents during pregnancy on preschool children’s AR, and further to explore the modification effects of regions and exclusive breastfeeding. Methods A multi-center population-based study was performed in 6 cities from 3 regions of China in 2011-2012. Maternal exposure to ambient PM2.5 and main chemical constituents(BC, OM, SO4²⁻, NO3⁻, NH4⁺) during pregnancy was assessed and a longitudinal prospective analysis was applied on preschool children’s AR. The modification effects of regions and exclusive breastfeeding were investigated. Results A total of 8.8% and 9.8% of children reported doctor-diagnosed allergic rhinitis(DDAR) and current hay fever, respectively, and 48.6% had less than 6 months of exclusive breastfeeding. The means of PM2.5 during pregnancy were 52.7μg/m³, 70.3μg/m³ and 76.4μg/m³ in the east, north and central south of China, respectively. Multilevel log-binomial model regression showed that each interquartile range(IQR) increase of PM2.5 during pregnancy was associated with an average increase in prevalence ratio (PR) of DDAR by 1.43(95% confidence interval(CI): 1.11, 1.84) and current hay fever by 1.79(95%CI: 1.26, 2.55), respectively. Among chemical constituents, black carbon (BC) had the strongest associations. Across 3 regions, the eastern cities had the highest associations, followed by those in the central south and the north. For those equal to or longer than 6 months of exclusive breastfeeding, the associations were significantly reduced. Conclusions Children in east of China had the highest risks of developing AR per unit increase of maternal exposure to PM2.5 during pregnancy, especially BC constituent. Remarkable decline was found in association with an increase in breastfeeding for ≥6 months, in particular in east of China.
Background Northern China has severe air pollution, especially in winter. Fractional exhaled nitric oxide (FeNO) is an established biomarker of airway inflammation. Aim To study associations between ambient temperature, air pollution and FeNO in university students in northern China. Methods We performed a panel study in 67 university students without asthma diagnosis in the city of Taiyuan. FeNO was measured 6 times, over one heating season. Outdoor PM10, PM2.5, SO2, NO2 and O3 were measured at a fixed location in the campus. SO2, NO2 and O3 were measured 7 days (24 h/day) before the FeNO test. PM2.5 and PM10 were measured at different lag times (lag 1 day to lag 7 days). Temperature and carbon monoxide (CO) data were collected from a nearby monitoring station (lag 7). Linear mixed models were applied to study associations between exposure and FeNO, adjusting for gender, age, current smoking, height and furry pet or pollen allergy. Results The overall geometric mean (GM) of FeNO was 17.2 ppb. GM of FeNO was lowest (12.9 ppb) in January and highest (20.0 ppb) in April. The range of lag 7 pollution was 105.0–339.0 μg/m³ for PM10, 72.0–180.0 μg/m³ for PM2.5, 36.0–347.0 μg/m³ for SO2, 26.0–69.0 μg/m³ for NO2, 31.0–163.0 μg/m³ for O3 and 0.93–3.14 mg/m³ for CO. The lag 7 temperature ranged from −4.5 to 20.1 °C. FeNO was consistently higher at higher outdoor temperature (p < 0.001). In multi-pollutant models with temperature adjustment, PM10, PM2.5 and SO2 were associated with FeNO (all p-values <0.001). In contrast, CO was negatively associated (protective) with FeNO (p < 0.001). Associations between exposure and FeNO were similar in men and women. Conclusion PM10, PM2.5 and SO2 and outdoor temperature can be associated with airway inflammation, measured as FeNO, in young adults in northern China while CO could be negatively associated with FeNO.
Background: Indoor microbiome exposure is associated with asthma, rhinitis and eczema. However, no studies report the interactions between environmental characteristics, indoor microbiome and health effects in a repeated cross-sectional framework. Methods: 1,279 and 1,121 preschool children in an industrial city (Taiyuan) of China were assessed for asthma, rhinitis and eczema symptoms in 2012 and 2019 by self-administered questionnaires, respectively. Bacteria and fungi in classroom vacuum dust were characterized by culture-independent amplicon sequencing. Multi-level logistic/linear regression was performed in two cross-sectional and two combined models to assess the associations. Results: The number of observed species in bacterial and fungal communities in classrooms increased significantly from 2012 to 2019, and the compositions of the microbial communities were drastically changed (p
The aim of this study is to investigate the status of child's health including allergy and asthma and home environment in Korea and to explore the association between them. This study is based on self-administered questionnaires and 2740 out of 5107 surveys had been collected and a response rate was 53.7%. Frequent symptoms were rhinitis last 12 month, doctor-diagnosed rhinitis and eczema. Children living in single-family or row houses have shown significantly more eczema and old housing residents has shown more wheezing and coughing than newly built housing residents. Dampness showed different distribution by housing characteristics. Condensation, mold and damp stain were found more often in single family houses and houses built earlier. Children living in homes with dampness showed statistically significant association with allergic symptoms. From these statements it could be expected that dampness is found by different housing character and the found dampness is related to allergy symptoms.
Background Increasing prevalence and worldwide variation in asthma and other atopic diseases suggest the influence of environmental factors, at least one possibly related to socioeconomic wellbeing. This paper examines the relationship of symptoms of asthma, rhinitis and eczema with gross national product per capita (GNP per capita). Methods The prevalences of atopic symptoms in 6‐7- and 13‐14-year-old children were assessed in 91 centres (from 38 countries) and 155 centres (from 56 countries), respectively, in the International Study of Asthma and Allergy in Childhood (ISAAC). These symptoms were related to 1993 GNP per capita for each country as reported by the World Bank. The relationships between symptoms of atopic diseases and infant mortality, the human development index and 1982 GNP per capita were also considered. Results The countries in the lowest quartile of GNP per capita have the lowest median positive responses to all the questions on symptoms of asthma, rhinitis and eczema. There was a statistically significant positive association between wheeze in the last 12 months and GNP per capita in the 13‐14-year age group, but not in the 6‐7-year age group. There was also a positive association between GNP per capita and eczema in both age groups. Conclusions The positive associations between GNP per capita and atopic symptoms being of only moderate strength suggests that the environmental factors are not just related to the wealth of the country.
In order to evaluate the prevalence of childhood asthma, allergic diseases and pneumonia in Urumqi City, China, as well as its associations with housing and home characteristics, a cross-sectional study was performed in 4618 children (81.7% response rate, average age 4.7±0.9 year, boys accounting for 53.7%). Questions on children’s asthma and allergic diseases were from the International Study on Asthma and Allergies in Childhood (ISAAC) and were integrated with questions on the home environment from the Dampness in Buildings and Health (DBH) study, slightly modified to account for Chinese building characteristics and life habits. The prevalences of physician diagnosed asthma, allergic rhinitis (AR) and pneumonia were 3.6%, 8.7% and 40.9%, respectively. One fourth of children reported wheezing and more than 40% AR symptoms in the last 12 months. Controlling for confounding factors, positive associations were found for home mold/dampness and wheezing (adjusted odds ratio, aOR 1.33, 95% CI 1.07–1.66), AR symptoms (1.34, 1.09–1.64) last 12 months and physician diagnosed pneumonia (1.33, 1.09–1.62). Floor material by wood, PVC or carpeting; and walls by wallpaper, painting or wood material, were positively associated with AR symptoms. Home environmental tobacco smoke (ETS) was positively associated with wheezing (1.23, 1.04–1.46) and pneumonia (1.25, 1.07–1.45). In conclusion, there was a relatively high prevalence of asthmatic and AR symptoms and diagnosed pneumonia in preschool children in Urumqi. Home signs of mold growth or dampness, windowpane condensation, as well as ETS and interior surface materials emitting chemicals were risk factors for allergic symptoms and pneumonia.
BACKGROUND—A critical review was conducted of the quantitative literature linking indoor air pollution from household use of biomass fuels with acute respiratory infections in young children, which is focused on, but not confined to, acute lower respiratory infection and pneumonia in children under two years in less developed countries. Biomass in the form of wood, crop residues, and animal dung is used in more than two fifths of the world's households as the principal fuel. METHODS—Medline and other electronic databases were used, but it was also necessary to secure literature from colleagues in less developed countries where not all publications are yet internationally indexed. RESULTS—The studies of indoor air pollution from household biomass fuels are reasonably consistent and, as a group, show a strong significant increase in risk for exposed young children compared with those living in households using cleaner fuels or being otherwise less exposed. Not all studies were able to adjust for confounders, but most of those that did so found that strong and significant risks remained. CONCLUSIONS—It seems that the relative risks are likely to be significant for the exposures considered here. Since acute lower respiratory infection is the chief cause of death in children in less developed countries, and exacts a larger burden of disease than any other disease category for the world population, even small additional risks due to such a ubiquitous exposure as air pollution have important public health implications. In the case of indoor air pollution in households using biomass fuels, the risks also seem to be fairly strong, presumably because of the high daily concentrations of pollutants found in such settings and the large amount of time young children spend with their mothers doing household cooking. Given the large vulnerable populations at risk, there is an urgent need to conduct randomised trials to increase confidence in the cause-effect relationship, to quantify the risk more precisely, to determine the degree of reduction in exposure required to significantly improve health, and to establish the effectiveness of interventions.
Abstract Ten researchers from the Nordic countries have reviewed the literature on early exposure in childhood, to pets and the risk of sensitisation/allergy. A search of the literature resulted in identification of about 1200 articles, of which 89 were selected for further examination. The group concluded that all exposure to pets involves a risk of sensitisation. Exposure in infancy involves an increased risk (normally RR = 1–1,5) of sensitisation and to a lesser degree of the development of symptoms. The group also concluded that pet allergens are present “everywhere”, as a result of people bringing allergens in their clothing, etc. The group concluded as a recommendation, that families with atopic individuals should wait until the child is at least two years old before getting a pet.