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Early-life exposure to home dampness associated with health effects among children in Chongqing, China
Building and Environment 94 (2015) 327e334
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Building and Environment journal homepage: www.elsevier.com/locate/buildenv
Early-life exposure to home dampness associated with health effects among children in Chongqing, China Han Wang a, b, Baizhan Li a, b, *, Wei Yu a, b, Juan Wang a, c, Dan Norback c a
Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, China National Center for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing, China c Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Uppsala SE-751, Sweden b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 May 2015 Received in revised form 24 August 2015 Accepted 25 August 2015 Available online 29 August 2015
Associations between early-life exposure to perinatal dampness problems and health effects among 2917 children (3e6 years) were evaluated in this study. After adjusted for gender, age, family history of asthma or allergies, environmental tobacco smoke exposure, gestation age and house location in the logistic regression models, perinatal exposure to dampness indicators was observed to be strongly associated with some respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night, rhinitis and eczema. The prevalence of theses respiratory and allergic symptoms in the last 12 months was significantly increased with perinatal-only exposure to most dampness indicators and was further increased with continuous exposure (perinatal plus current exposure). There was almost no such significant increase with current-only exposure. This study found less association between perinatal-only exposure and doctordiagnosed diseases, and these associations may be explained by recall bias. Early-life exposure to perinatal dampness reported by parents was significantly associated with some current respiratory and allergic symptoms among children in Chongqing, China. Hence, it is necessary to pay attention to early living environment, especially home dampness, although the mechanisms are still unclear. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Dampness Perinatal exposure Respiratory Allergic symptoms Association Children
1. Introduction In recent years, more and more studies have observed that selfreported dampness in buildings is associated with an increase of respiratory illness, including cough, wheezing, airway infections and respiratory symptoms [1e7]. Multidisciplinary reviews have concluded that there are adverse health effects of dampness and mold in buildings, especially on asthma and allergies. In particular, dampness and odor at home might result in an increased risk of childhood asthma [8e11]. Building dampness, as an important public health issue, contributes to asthma and allergies among children in many geographical regions [12,13]. However, there are few studies and reports on the health effects of early-life exposure to home dampness, and the understanding about the influence of early-life exposure to dampness problems on health is insufficient, especially among children [14,15].
* Corresponding author. The College of Urban Construction and Environmental Engineering, Chongqing University, (Campus B), Chongqing, 400045, China. Tel: þ86 23 65127531, Fax: þ86 23 65127532. E-mail address: [email protected] (B. Li). http://dx.doi.org/10.1016/j.buildenv.2015.08.024 0360-1323/© 2015 Elsevier Ltd. All rights reserved.
China is a developing country under continued urbanization, and its morbidity rate of asthma among children under the age of 15 has increased sharply in recent years [16,17]. Rapid urbanization has caused much pressure on the indoor environment, which may contribute to the increase of asthma and related health problems. Studies in China have indicated that indoor environmental factors, including home dampness, may influence the prevalence of asthma and allergies among college students, school children and preschool children [18e21]. Chongqing is a city with high indoor relative humidity, low indoor wind speed and large rainfall all over the year which can increase the risk for pronounced dampness problems, and the higher asthma morbidity as compared to other cities in China [17,22e24]. Associations between exposure to dampness in residential buildings and health have already been studied in Chongqing recently [21]. However, there are no studies that have reported on exposure in early life and preschool children's health in Chongqing or other cities that have the same climate feature in China. Hence, the objective of this study is to assess whether early-life exposure to indoor dampness in homes is associated with the development of asthma, allergies and related symptoms among pre-school children in Chongqing, China.
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2. Material and methods
“Doctor-diagnosed asthma”: Has your child been diagnosed with asthma by a doctor? (yes vs. no)
This study is based on a cross-sectional questionnaire research in Chongqing, and carried out as the first phase of the study “China, Child, Homes, Health” (CCHH) [25]. Questionnaires were distributed to the parents of all 7177 children in randomly selected pre-schools in three different districts in Chongqing and were collected one week later by the teachers. The questionnaire survey has been carried out from December 2010 to April 2011.
“Doctor-diagnosed rhinitis”: Has your child been diagnosed with hay fever or allergic rhinitis by a doctor? (yes vs. no)
2.1. Questionnaire The questionnaire was adopted from a Swedish study on preschool children and was slightly modified for the consideration of Chinese conditions [1,18]. The questionnaire includes about 80 questions on demographic data, family conditions, dwelling characteristics, home dampness and health conditions of the child and the parent who answered the questionnaire [21,25]. This paper mainly focus on two parts: home dampness and health conditions of the child. The questionnaire asked some dampness problems of the entire resident environment in the perinatal period, and all questions on home dampness are as follows: “Current visible mold”: Have you noticed any visible mold on the floor, walls or ceiling in the child's room? (yes vs. no) “Current damp stains”: Have you noticed any visible damp stains on the floor, walls or ceiling in the child's room? (yes vs. no) “Current condensation on windows”: In the winter, did condensation or moisture occur on the inside or at the bottom of windows (windowpanes) in the child's room? (more than 25cm / 5-25cm / less than 5cm / no) “Current moldy odor”: Have you been bothered by moldy smell in your residence during the last 3 months? (frequently/ sometimes/ never) “Perinatal visible mold or damp stains”: When the child was born, have you noticed visible mold or damp stains on the floor, walls or ceiling? (frequently/ sometimes/ never) “Perinatal condensation on windows”: When the child was born, did condensation or moisture occur on the inside, at the bottom, of windows (windows) in the winter period? (frequently/ sometimes/ never) “Perinatal moldy odor”: When the child was born, have you been bothered by moldy smell in your residence? (frequently/ sometimes/ never) The questions on children's health covered respiratory and allergic symptoms in the last 12 months and doctor-diagnosed diseases, as follows: “Wheezing in the last 12months”: In the last 12 months, has your child had wheezing or whistling in the chest? (yes vs. no) “Cough at night in the last 12 months”: In the last 12 months, has your child had a dry cough at night for more than two weeks, apart from cough associated with a cold or chest infection? (yes vs. no) “Rhinitis in the last 12 months”: In the last 12 months, has your child had a problem with sneezing, or a runny, or a blocked nose when he / she did not have a cold or the flu? (yes vs. no) “Eczema in the last 12 months”: Has your child had eczema at any time in the last 12 months? (yes vs. no)
“Family history of asthma and allergies”: Does asthma or allergic diseases exist in the family? (yes vs. no) The answers were categorized into two groups: “Yes” (when the answer is “Frequently” or “Sometimes”) and “No” (when the answer is “Never”). The indicator “Condensation on windows” was classified in two categories: “Yes” (when the answer is “More than 25 cm”, “5e25 cm” and “less than 5 cm”) and “No” (when the answer is “no”). The answer “Don't know” was excluded from the analyses. A combined dampness indicator “Current visible mold or damp stains” was defined as “Yes” if visible mold or damp stains was noticed in the child's room, otherwise it was classified as “No”. Finally, home dampness includes three indicators: visible mold or damp stains, condensation on windows and moldy odor. Family history of asthma and allergies was classified as “Yes” if father, mother or siblings living in this house had asthma or allergic diseases and as “No” if none of them had these diseases. Exposure duration depends on the time when the exposure occurred. Perinatal exposure was defined as exposure occurred when the child was born, and current exposure is referring to the situation in the child's room when the questionnaire was answered. In order to evaluate the independent influence of perinatal-only exposure to dampness, all dampness indicators were classified into four categories according to the time when the dampness indicators were found by parents: “no exposure” (if neither perinatal nor current dampness indicators were reported), “perinatal-only exposure” (if only perinatal dampness indicators were reported), “current-only exposure” (if only current dampness indicators were reported) and “continuous exposure” (if both perinatal and current dampness indicators were reported). 2.2. Data analysis Statistical analysis was performed using the Statistical Package for Social Science (SPSS 18.0). Initially, associations were analyzed by chi-squared test for contingency tables. Then associations between home dampness indicators and health effects were calculated by multiple logistic regression, adjusting for gender of the child (boy vs. girl), age of the child (3 years vs. 4 years vs. 5 years vs. 6 years), family history of asthma or allergies (yes vs. no), environmental tobacco smoke exposure in uterus or during the first year of life (ETS exposure) (yes vs. no), gestation age (36 weeks vs. 37e40 weeks vs. 41 weeks) and house location (urban vs. rural or suburban). Adjusted odd ratio (AOR) with 95% confidence interval (CI) was calculated. P-value less than 0.05 indicated a statistically significant level. 2.3. Ethics statement The study complies with the Helsinki Declaration. The study and the consent procedure were approved by the Medical Research Ethics Committee of the School of Public Health, Fudan University. A written informed consent was obtained from the participants. 3. Results Among the selected 7117 children, 5299 children participated, and the response rate is 74.5%. One parent of each child answered the questionnaire. The study was limited to the child who has lived
H. Wang et al. / Building and Environment 94 (2015) 327e334
in the same house since birth and ranging from 3 to 6 years old. Questionnaires with missing information on the child's gender were excluded. Finally, 2917 questionnaires were included in this study. Tables 1e3 shows the prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by personal and family factors. The prevalence of wheezing and rhinitis in the last 12 months, doctor-diagnosed asthma and rhinitis was significantly higher among boys than girls. The prevalence of wheezing, cough at night and eczema in the last 12 months decreased with the increase of age, and it got the lowest value among the oldest children (6 years). The prevalence of asthma and allergic symptoms in the last 12 months and doctor-diagnosed asthma and rhinitis was more common for children with family history of asthma and allergies. Rhinitis in the last 12 months and doctor-diagnosed rhinitis was more common among children with ETS exposure, and eczema in the last 12 months was more common in children who were born early (gestation age 36 weeks). The prevalence of wheezing and rhinitis in the last 12 months, as well as doctordiagnosed asthma and rhinitis, was higher in urban as compared to rural/suburban areas. The child's gender and age, family history of asthma and allergies, ETS exposure, gestation age and house location were significantly associated with at least one of the asthma and allergic symptoms and thus these factors were included in the regression model as confounders. The prevalence of perinatal and current home dampness indicators is given in Table 4. The house location had significant influence on the prevalence of perinatal and current dampness problems. Visible mold or damp stains was more frequent in rural/ suburban as compared to urban areas (18.8% vs. 13.3% for perinatal exposure, 13.0% vs. 8.5% for current exposure). The condensation on windows was found more common in urban areas (15.4% vs. 9.4% for current exposure). The prevalence of moldy odor was reported higher in rural/suburban as compared to urban areas (15.9% vs. 10.7% for perinatal exposure, 14.5% vs. 10.6% for current exposure). Tables 5 and 6 shows the prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by perinatal and current dampness indicators. Higher rates of wheezing, cough at night and rhinitis in the last 12 months were found among children with perinatal or current exposure to home dampness. There was significantly more prevalence of eczema in the last 12 months when condensation on windows or moldy odor was noticed in the perinatal period. Children in homes with current or perinatal exposure to condensation on windows had more risk to be diagnosed with asthma and rhinitis by a doctor. In general, children in homes with perinatal or current dampness problems had more asthma and allergies and related symptoms.
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As a next step, associations were analyzed by multiple logistic regression models, adjusting for confounding factors, shown in Table 7. Wheezing in the last 12 months was significantly associated with exposure to dampness except current exposure to condensation on windows. The associations between cough at night in the last 12 months and all dampness indicators reported in perinatal period or currently were found. With perinatal exposure to dampness, the prevalence of rhinitis in last 12 months was significantly higher, and the risk of having rhinitis in the last 12 months was increased when current moldy odor was reported. Eczema in the last 12 months was significantly associated with perinatal condensation on windows and current visible mold or damp stains respectively. Perinatal exposure to moldy odor was a risk factor for doctor-diagnosed asthma, and the prevalence of doctor-diagnosed rhinitis was significantly influenced by perinatal and current condensation on windows. Respiratory and allergic symptoms in the last 12 months and doctor-diagnosed diseases reported by parents were strongly associated with most dampness indicators involved in this study. The strongest association in all results was found between perinatal exposure to moldy odor and wheezing in the last 12 months (AOR: 2.18; 95% CI: 1.65e2.88). The independent influence of perinatal exposure on children's health is present in Table 8, With no perinatal and current exposure as reference, perinatal-only exposure to dampness indicators was significantly associated with some the respiratory and allergic symptoms in the last 12 months, and perinatal-only exposure to condensation on windows was a risk factor for all symptoms involved in the study. The association between current-only exposure to condensation on windows and wheezing in the last 12 months was found and other associations between current-only exposure and respiratory and allergic symptoms in the last 12 months were not significant. The prevalence of respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night and rhinitis in the last 12 month, were significantly increased with continuous exposure (perinatal plus current exposure) to dampness while these associations were not found with current-only exposure. For doctor-diagnosed asthma, the prevalence was higher with perinatal-only exposure to moldy odor and continuous exposure to condensation on windows. The risk of doctor-diagnosed rhinitis reported by parents was significantly increased with perinatal-only, current-only and continuous exposure to condensation on windows, when using no exposure as reference. The independent influence on some respiratory and allergic symptoms in the last 12 months was significant with perinatal-only exposure to most dampness indicators, and in general the prevalence of these symptoms was further increased with continuous exposure. However, the significant influence of
Table 1 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by gender and age.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Total (n ¼ 2917)
Gender Boy (n ¼ 1467)
Girl (n ¼ 1450)
N (%)
N (%)
N (%)
303 (21.1) 265 (18.5)
262 (18.4) 263 (18.4)
588 199 156 106
533 188 98 78
565 (19.8) 528 (18.4) 1121 387 254 184
(39.0) (13.5) (8.9) (6.5)
(40.7) (13.8) (10.8) (7.4)
Age
(37.4) (13.3) (6.9) (5.5)
Pvalue
3 years (n ¼ 667)
4 years (n ¼ 952)
5 years (n ¼ 861)
6 years (n ¼ 437)
N (%)
N (%)
N (%)
N (%)
176 (19.0) 172 (18.5)
168 (19.8) 143 (16.9)
379 150 83 58
315 92 73 57
0.074 152 (23.2) 0.962 157 (23.9) 0.072 262 (39.6) 0.702 100 (15.3) <0.001 63 (9.6) 0.047 35 (5.4)
(40.5) (16.1) (8.9) (6.2)
(37.2) (10.8) (8.6) (6.8)
69 (16.2) 56 (13.1) 165 45 35 34
(38.4) (10.6) (8.2) (8.0)
Pvalue
0.035 <0.001 0.538 0.002 0.882 0.365
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in different gender and age groups were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between different gender and age groups, and bold represents the P-value less than 0.05.
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Table 2 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by personal and family factors. Family history of asthma and allergies
ETS exposure
Yes (n ¼ 322)
Yes (n ¼ 1498)
No (n ¼ 2515)
N (%)
Pvalue
N (%)
Wheezing in the last 12 months 108 (34.3) 93 (29.4) Cough at night in the last 12 months Rhinitis in the last 12 months 173 (54.7) Eczema in the last 12 months 57 (18.2) Doctor-diagnosed asthma 81 (25.6) Doctor-diagnosed rhinitis 53 (17.2)
N (%)
Gestation age No (n ¼ 1367)
P36 weeks value (n ¼ 146)
N (%)
N (%)
<0.001 309 (21.1) <0.001 282 (19.1)
247 (18.3) 240 (17.8)
0.059 29 (20.3) 0.364 35 (24.8)
369 (20.2) 342 (18.5)
153 (18.7) 138 (16.9)
0.669 0.078
924 324 170 128
<0.001 0.011 <0.001 <0.001
495 176 115 73
0.017 47 (32.6) 0.386 28 (19.6) 0.456 9 (6.4) 0.032 12 (8.3)
726 252 165 113
322 96 73 51
0.275 0.029 0.581 0.592
608 208 137 109
(41.1) (14.2) (9.3) (7.4)
N (%)
Pvalue
442 (17.8) 427 (17.2) (37.0) (13.0) (6.8) (5.1)
N (%)
41 weeks (n ¼ 834)
37e40 weeks (n ¼ 1868)
(36.7) (13.0) (8.5) (5.4)
(39.4) (13.8) (8.9) (6.2)
(39.2) (11.7) (8.9) (6.2)
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in different answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between different answers to each factor, and bold represents the P-value less than 0.05.
Table 3 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by house location. House location
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Rural/suburban (n ¼ 754)
Urban (n ¼ 2114)
N (%)
N (%)
171 131 246 106 50 32
389 387 854 274 202 149
(23.2) (17.8) (33.2) (14.5) (6.8) (4.4)
P-value
(18.7) (18.6) (41.0) (13.2) (9.7) (7.2)
0.009 0.606 <0.001 0.362 0.018 0.008
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Rural/Suburban” and “Urban” answers to house location were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Rural/Suburban” and “Urban” answers to each factor, and bold represents the Pvalue less than 0.05.
Table 4 Prevalence of dampness indicators at homes with different house locations. House location
Perinatal visible mold or damp stains Perinatal condensation on windows Perinatal moldy odor Current visible mold or damp stains Current condensation on windows Current moldy odor
Total (n ¼ 2868)
Rural/suburban (n ¼ 754)
Urban (n ¼ 2114)
N (%)
N (%)
N (%)
136 261 104 87 62 93
274 804 198 165 283 194
410 1065 302 252 345 287
(14.7) (38.5) (12.0) (9.6) (13.8) (11.6)
(18.8) (36.1) (15.9) (13.0) (9.4) (14.5)
P-value
<0.001 0.135 <0.001 0.001 <0.001 0.007
(13.3) (39.3) (10.7) (8.5) (15.4) (10.6)
1) N and % (within the parentheses) of responses of observed dampness indicators in different location of the houses were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on distributions of dampness indicators in different location of the houses, and bold represents the P-value less than 0.05.
Table 5 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by perinatal dampness indicators.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Perinatal visible mold or damp stains
Perinatal condensation on windows
Perinatal moldy odor
Yes
No
Yes
No
Yes
No
N (%)
N (%)
N (%)
N (%)
N (%)
N (%)
125 104 183 55 42 30
420 410 916 323 207 148
253 235 467 168 110 86
292 276 618 210 136 89
96 82 137 46 37 17
388 380 840 278 176 137
(30.3) (25.4) (44.3) (13.5) (10.3) (7.4)
P-value
(17.8) (17.3) (38.5) (13.6) (8.7) (6.2)
<0.001 <0.001 0.025 0.967 0.297 0.375
(23.8) (22.1) (43.6) (15.8) (10.3) (8.1)
P-value
(17.2) (16.2) (36.1) (12.3) (8.0) (5.2)
<0.001 <0.001 <0.001 0.009 0.034 0.002
(32.0) (27.2) (45.2) (15.3) (12.4) (5.6)
P-value
(17.5) (17.1) (37.8) (12.5) (7.9) (6.2)
<0.001 <0.001 0.013 0.165 0.009 0.718
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Yes” and “No” answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Yes” and “No” answers to each indicator, and bold represents the P-value less than 0.05.
H. Wang et al. / Building and Environment 94 (2015) 327e334
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Table 6 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by current dampness indicators.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Current visible mold or damp stains
Current condensation on windows
Current moldy odor
Yes
Yes
Yes
No
P-value
N (%)
N (%)
74 67 108 46 31 21
421 415 908 314 199 141
(29.8) (27.2) (43.20 (18.7) (12.5) (8.6)
<0.001 <0.001 0.128 0.018 0.029 0.105
(17.8) (17.5) (38.3) (13.2) (8.4) (5.9)
No
P-value
N (%)
N (%)
75 94 150 53 44 34
422 356 804 283 181 123
(21.9) (27.4) (43.6) (15.4) (12.8) (10.0)
(19.7) (16.6) (37.3) (13.2) (8.4) (5.7)
0.339 <0.001 0.024 0.262 0.008 0.003
No
P-value
N (%)
N (%)
88 74 138 43 36 20
386 374 817 277 172 130
(30.9) (25.7) (48.3) (15.0) (12.6) (7.1)
(17.6) (17.0) (37.2) (12.6) (7.8) (5.9)
<0.001 <0.001 <0.001 0.243 0.006 0.438
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Yes” and “No” answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Yes” and “No” answers to each indicator, and bold represents the P-value less than 0.05.
Table 7 Associations between perinatal exposure to dampness and health effects by adjusted odds ratio (AOR) with 95% confidence interval (95% CI).
Wheezing last 12 months Cough at night last 12 months Rhinitis last 12 months Eczema last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Perinatal visible mold or damp stains
Perinatal condensation on windows
Perinatal moldy Current visible mold or damp Current condensation on odor stains now windows now
Current moldy odor
1.90 (1.48,2.43)
1.44 (1.18,1.75)
2.18 (1.65,2.88) 1.75 (1.28,2.38)
1.11 (0.83,1.49)
1.93 (1.44,2.57)
1.56 (1.20,2.02)
1.42 (1.16,1.73)
1.87 (1.40,2.50) 1.64 (1.20,2.25)
1.79 (1.36,2.35)
1.65 (1.22,2.22)
1.25 (1.00,1.56)
1.29 (1.10,1.52)
1.39 (1.08,1.79) 1.21 (0.92,1.60)
1.22 (0.96,1.55)
1.54 (1.19,2.00)
0.97 (0.70,1.33)
1.36 (1.09,1.71)
1.30 (0.92,1.84) 1.43(1.00,2.04)
1.22 (0.88,1.69)
1.25 (0.87,1.79)
1.05 (0.72,1.53)
1.16 (0.88,1.53)
1.56 (1.05,2.33) 1.28 (0.83,1.99)
1.41 (0.97,2.06)
1.43 (0.94,2.17)
1.22 (0.80,1.86)
1.51 (1.10,2.09)
0.90 (0.53,1.53) 1.47 (0.89,2.42)
1.76 (1.16,2.68)
1.08 (0.65,1.81)
1) Adjustments were made for gender, age, family history of asthma and allergies, ETS exposure, gestation age and house location. 2) Adjusted odds ratio (AOR) was estimated for dampness indicators with “Yes” answer compared with “No” answer. The AOR of dampness indicators with “No” answer is 1, and bold represents the P-value less than 0.05.
Table 8 Associations between exposure to dampness and health effects by adjusted odds ratio (AOR) with 95% confidence interval (95% CI). Visible mold or damp stains Perinatal-only Wheezing last 12 months Cough at night last 12 months Rhinitis last 12 months Eczema last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Current-only
Condensation on windows Continuous
Perinatal-only
Current-only
Moldy odor Continuous
Perinatal-only
Current-only
Continuous
1.84 (1.34,2.52) 1.34 (0.84,2.15) 2.35 (1.51,3.66) 1.63 (1.30,2.06) 1.82 (1.03,3.21) 1.22 (0.87,1.72) 1.89 (1.26,2.82) 1.31 (0.84,2.05) 2.64 (1.80,3.88) 1.54 (1.10,2.14) 1.50 (0.95,2.38) 1.85 (1.16,2.95) 1.34 (1.05,1.72) 1.61 (0.89,2.93) 1.95 (1.42,2.67) 1.55 (1.02,2.37) 1.07 (0.67,1.72) 2.45 (1.66,3.62) 1.40 (1.06,1.85) 1.20 (0.81,1.79) 1.12 (0.74,1.71) 1.27 (1.04,1.54) 0.91 (0.54,1.55) 1.44 (1.10,1.89) 1.20 (0.83,1.73) 1.27 (0.88,1.85) 1.84 (1.29,2.64) 0.95 (0.63,1.43) 1.50 (0.91,2.47) 1.37 (0.81,2.35) 1.67 (1.28,2.19) 1.76 (0.92,3.38) 1.40 (0.96,2.05) 1.06 (0.63,1.78) 0.86 (0.48,1.53) 1.52 (0.95,2.43) 0.83 (0.49,1.40) 1.21 (0.65,2.26) 1.08 (0.54,2.18) 1.01 (0.72,1.43) 0.88 (0.34,2.29) 1.58 (1.04,2.40) 1.83 (1.06,3.14) 1.17 (0.62,2.21) 1.69 (0.96,2.99) 1.02 (0.57,1.82) 1.50 (0.75,3.01) 1.50 (0.72,3.13) 1.76 (1.19,2.60) 2.37 (1.02,5.49) 2.01 (1.21,3.34) 0.77 (0.35,1.73) 1.05 (0.51,2.17) 1.09 (0.53,2.25)
1) Adjustments were made for gender, age, family history of asthma and allergies, ETS exposure, gestation age and house location. 2) Adjusted odds ratio (AOR) was estimated for dampness indicators with no exposure as reference and the AOR was 1, and bold represents the P-value less than 0.05.
perinatal-only exposure was less consistently found on the doctordiagnosed diseases, and few associations between current-only exposure and health outcomes were found as compared to no exposure. 4. Discussion As most epidemiological studies, this study used subjective reports for the assessment of the associations between dampness exposure and health outcomes. Selection bias, non-response bias, recall bias and confounders could influence the results [11,26,27]. In this study, Cluster random sampling used in this study and high
response rate indicated that the impact of selection bias was limited. Non-response bias was evaluated by re-inviting initial respondents to complete a short questionnaire, and there were no significant differences in the same questions between 5299 responders and 206 non-respondents [21]. Recall bias was inevitable when all information was collected through participant reports via questionnaire [27]. Participants were asked about the dampness problems at the perinatal period and currently, so respondents were likely to have forgotten about their exposures in earlier period. Large sample size and accurate and clear questions designed could reduce the influence of recall bias to a certain extent. Respondents might recall a prior exposure differently
332
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depending on their children's disease status, and perinatal exposure to dampness would be over-reported by parents with current exposure [27]. Some studies take objective inspections to measure dampness and make comparison with the results of self-reported questionnaire, and most similar studies have shown that occupants reported more dampness problems, while there are some studies where the occupants have reported less dampness than inspectors [8,28,29]. The associations between observation on dampness made by inspector and health effects are also different from that between parental-reported dampness and illness [8,30]. In this study, the results could be susceptible to subjectivity from investigator, and the associations could be over-estimated. So, the possible impact on associations would be considered with appropriate data analysis and comparison of results in previous study to eliminate the influence of recall bias as much as possible. Confounding factors were also considered in this study. Residential characteristics and human behavioral habit would improve or deteriorate indoor dampness conditions [18]. In order to avoid the influence of residential characteristics and human behavioral habits on the results, stratified analysis was performed in this study. Finally, with the common confounders, such as gender of the child, age of the child, family history of asthma or allergies, environmental tobacco smoke exposure in uterus or during the first year of life, gestation age, house location were included in the logistic regression model as a confounding factor and other variables were found not to meet the criteria of a confounder [21,27,31]. Thus, the impact of confounders on the results was greatly reduced. Dampness is a generic term and there has been little to no substantive progress in defining what “dampness” is [32]. In this study, dampness is overall condition of moisture in buildings and is defined as presence of three indicators: visible mold or damp stains, condensation on windows and moldy odor. The purpose of this paper is to evaluate the influence of early-life exposure to dampness on children's asthma, allergies and related symptoms, and all the data about dampness and health were self-reported via questionnaire. Visible mold, damp stains and moldy odor are common indicators in previous studies [2,7,8,15]. Condensation on windows is not considered generally especially in early-life exposure, however condensation could cause microbial growth and chemical process, e.g. mite and irritant substances and/or allergens, that may influence children's health [1,8]. In Chongqing, high indoor relative humidity (the relative humidity is greater than 70% in most of the year, and in winter the percentage of time with relative humidity above 70% was 94%), and low indoor wind speed (the annual average wind speed is about 0.107 m/s, and the average wind speed is about 0.087 m/s in winter) may result in condensation on windows [22e24]. Thus, condensation on windows, as dampness indicator, was added in this study to evaluate the health effects of dampness, and these three indicators could effectively represent the severity of dampness in buildings. In this study, perinatal exposures were considered as early-life exposures, and the health effects were divided into two parts: respiratory and allergic symptoms in the last 12 months (wheezing, cough at night, rhinitis and eczema in the last 12 months) and doctor-diagnosed diseases (doctor-diagnosed asthma and rhinitis). In order to evaluate the independent health effects of perinatalonly exposure to dampness, exposure to home dampness was divided into four categories and the category “no perinatal and current exposure” was taken as reference in the regression model, and the results of perinatal-only exposure with no exposure and continuous exposure (perinatal plus current exposure) with current-only exposure were compared. Because the respondents were likely to more prone to remember and report their past exposure in the perinatal period when the current exposure was found, and comparison as described above may effectively reduce
the influence of recall bias to accurately evaluate the independent health effects of perinatal-only exposure. In this study, perinatal-only exposure to dampness problems was found to be associated with respiratory and allergic symptoms in the last 12 months whether current exposure was reported by the parents or not. The risk of wheezing and cough at night in the last 12 months was generally higher with perinatal-only exposure as compared to no exposure, and it was consistent with the findings of similar studies [7,15,33e35]. The prevalence of rhinitis and eczema in the last 12 months was strongly related with perinatalonly exposure to visible mold or damp stains and condensation on windows. The results were in agreement with previous studies that have observed that the risk of self-reported allergic rhinitis and eczema among children was increased when exposed to visible mold and dampness in the early period of child growth, and few associations with condensation on windows was reported [2,15,36]. For influence of early-life exposure to dampness on respiratory and allergic symptoms, similar associations have been found by other studies as well [37e39]. Meanwhile, the prevalence of respiratory and allergic symptoms was further increased with continuous exposure, and these symptoms were more strongly related to dampness indicators when exposed in both the perinatal period and currently. This is in accordance with an Italian study [2]. All symptoms included in this study were in the last 12 months, and it was shown that early-life exposure to perinatal dampness could significantly influence the prevalence of some current respiratory and allergic symptoms, consistent with recent reports [2,15]. Thus, early-life exposure to perinatal dampness was strongly related with some current respiratory and allergic symptoms, and when both perinatal and current exposure was reported the risk could be further increased, while almost no such increase with current-only exposure was observed. For doctor-diagnosed diseases, there was less association found in this study. Condensation on windows was found as a risk factor for doctor-diagnosed rhinitis, and doctor-diagnosed asthma was associated with perinatal-only exposure to condensation on windows and moldy odor. It was shown in a Swedish cross-sectional study that self-reported current exposure to condensation on windows was significantly associated with doctor-diagnosed asthma and rhinitis [1]. However, few strong associations between self-reported condensation on windows and moldy odor in early phase of developmental stage and doctor-diagnosed asthma/ rhinitis have been found in similar studies [2,8,32]. Recent studies that used quantitative measures of indoor dampness, including professional inspections, did not find associations between doctordiagnosed asthma/allergy in children and different indexes of indoor dampness [32,40]. So, it is possible that recall bias is a explanation for the associations, and these associations involving doctor-diagnosed diseases should be further identified in following study, especially with quantitative method for assessing risk of dampness exposure. It is, however, to be noted that there are still unclear mechanisms for the associations between dampness problems and asthma, allergies and some other related symptoms. The most possible evidence includes the associations of microbial toxins and health effects in damp environment of Chongqing. However, the evidence is very limited to prove this [41,42]. According to previous studies, microbes were reported to be detected in typically moisture damaged environment [43,44]. Under the humid climate, the microbial toxins are able to exist for a long time, and may have influence on children's health in the long run. However, specific causative agents have not been established, and there are so many studies that have showed that the health effects associated with dampness cannot be explained by a single mechanism [11]. The age of having asthma, allergies and related symptoms and
H. Wang et al. / Building and Environment 94 (2015) 327e334
the development after getting similar health problems is not included in this study, so more studies are needed to take them into account to further identify specific health effects with exposure to dampness in different developmental stages among children. However, the initial results of the study suggest that to protect the child from dampness environment could reduce the adverse impact on children's health. Another limitation of this study is that all data on exposure and health effects were obtained using questionnaire. There are limitations on the possibility to draw conclusions on causality, and recall bias may lead to over-estimation of the true effects of subjectivity from respondents. Following studies to indentify the casual relationship between dampness and health effects should be assessed with quantitative techniques. 5. Conclusions In Chongqing, early-life exposures to home dampness in perinatal period were strongly associated with some respiratory and allergic symptoms in the last 12 month among children. The prevalence of respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night, rhinitis and eczema, was significantly increased with perinatal-only exposure to most dampness indicators, and was further increased with continuous exposure. There was no such increase of these symptoms with current-only exposure. The associations between doctor-diagnosed asthma/rhinitis and perinatal-only exposure to condensation on windows and moldy odor were found, and these associations should be further identified due to the impact of recall bias. Selfreported perinatal exposure to home dampness had adverse health effects and was a risk factor for some current respiratory and allergic symptoms in the last 12 months. So, early-exposure to dampness problems should receive more attention and the improvement of indoor environment is needed to avoid dampness environment in buildings, especially in the early period of children's growth. Following studies should focus on the causal relationship between home dampness and health effects and the mechanism of health effects related to dampness problems using objective metric for dampness and related problems. Acknowledge The study has been supported by the National Technology Support Project (2012BAJ02B06), the 111 Project (No.B13041), and “the Short-term International Academic fund” of Chongqing University 2015 Overseas Visiting Student Project (No. GJXSFX150210). References [1] C.G. Bornehag, J. Sundell, L. Hagerhad-Engman, T. Sigsggard, S. Janson, N. Aberg, et al., ‘Dampness’ at home and its association with airway, nose, and skin symptoms among 10,851 preschool children in Sweden: a cross-sectional study, Indoor Air 15 (Suppl. 10) (2005) 48e55. [2] M. Simoni, E. Lombardi, G. Berti, F. Rusconi, Piffer S. GruttanSL, et al., Mould/ dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study, Occup. Environ. Med. 62 (9) (2005) 616e622. [3] S.H. Cho, T. Reponen, G. LeMasters, L. Levin, J. Huang, T. Meklin, et al., Mold damage in homes and wheezing in infants, Ann. Allerg. Asthma Im. 97 (4) (2006) 539e545. [4] K.W. Tham, M.S. Zuraimi, D. Koh, F.T. Chew, P.L. Ooi, Associations between home dampness and presence of molds with asthma and allergy symptoms among young children in the tropics, Pediatr. Allergy Immunol. 18 (5) (2007) 418e424. [5] T. Antova, S. Pattenden, B. Brunekreef, J. Heinrich, P. Rudnai, F. Forastiere, H. Luttmann-Gibson, L. Grize, B. Katsnelson, H. Moshammer, B. Nikiforov, H. Slachtova, K. Slotova, R. Zlotkowska, T. Fletcher, Exposure to indoor mould and children's respiratory health in the PATY study, J. Epidemiol. Community Health 62 (8) (2008) 708e714. [6] R. Pirastu, C.P. Bellu, U. Pelosi, R. Pistelli, G. Accetta, A. Biggeri, Indoor exposure to environmental tobacco smoke and dampness: respiratory symptoms in
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Fisk, Public health and economic impact of dampness and mold, Indoor Air 17 (3) (2007) 226e235. [11] M.J. Mendell, A.G. Mirer, K. Cheung, M. Tong, J. Douwes, Respiratory and allergic health effects of dampness, mold and dampness-related agents: a review of the epidemiologic evidence, Environ. Health Persp. 119 (6) (2011) 748e756. [12] Institute of Medicine (IMO), Damp Indoor Spaces and Health, National Academies Press, Washington, DC, 2004. [13] World Health Organization (WHO), Guidelines for Indoor Air Quality: Dampness and Mould, World Health Organization, Copenhagen, 2009. [14] J.F. Gent, P.K. Ren, E. Triche, M.B. Bracken, T.R. Holford, B.P. Leaderer, Levels of household mold associated with respiratory symptoms in the first year of life in a cohort at risk for asthma, Environ. Health Persp. 110 (12) (2002) A781. [15] C.G. Tischer, C. Hohmann, E. Thiering, O. Herbarth, A. Muller, J. Henderson, et al., Meta-analysis of mould and dampness exposure on asthma and allergy in eight European birth cohorts: an ENRIECO initiative, Allergy 66 (12) (2011) 1570e1579. [16] B.Z. Li, R.M. Yao, Urbanisation and its impact on building energy consumption and efficiency in China, Renew. Energ 34 (9) (2009) 1994e1998. [17] National Cooperation Group on Childhood Asthma, A nationwide survey in China on prevalence of asthma in urban children, Zhonghua Er Ke Za Zhi 41 (2) (2003) 123e127. [18] Y.X. Sun, Y.P. Zhang, J. Sundell, Z. Fan, L. Bao, Dampness at dorm and its associations with allergy and airways infection among college students in China: a cross-sectional study, Indoor Air 19 (2) (2009) 174e182. [19] C.Y. Yang, J.F. Chiu, H.F. Chiu, W. Kao, Damp housing conditions and respiratory symptoms in primary school children, Pediatr. Pulm. 24 (2) (1997) 73e77. [20] H.Y. Wang, Y.Z. Chen, Y. Ma, W.K. Gary, C.K. 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Building and Environment journal homepage: www.elsevier.com/locate/buildenv
Early-life exposure to home dampness associated with health effects among children in Chongqing, China Han Wang a, b, Baizhan Li a, b, *, Wei Yu a, b, Juan Wang a, c, Dan Norback c a
Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, China National Center for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing, China c Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Uppsala SE-751, Sweden b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 May 2015 Received in revised form 24 August 2015 Accepted 25 August 2015 Available online 29 August 2015
Associations between early-life exposure to perinatal dampness problems and health effects among 2917 children (3e6 years) were evaluated in this study. After adjusted for gender, age, family history of asthma or allergies, environmental tobacco smoke exposure, gestation age and house location in the logistic regression models, perinatal exposure to dampness indicators was observed to be strongly associated with some respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night, rhinitis and eczema. The prevalence of theses respiratory and allergic symptoms in the last 12 months was significantly increased with perinatal-only exposure to most dampness indicators and was further increased with continuous exposure (perinatal plus current exposure). There was almost no such significant increase with current-only exposure. This study found less association between perinatal-only exposure and doctordiagnosed diseases, and these associations may be explained by recall bias. Early-life exposure to perinatal dampness reported by parents was significantly associated with some current respiratory and allergic symptoms among children in Chongqing, China. Hence, it is necessary to pay attention to early living environment, especially home dampness, although the mechanisms are still unclear. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Dampness Perinatal exposure Respiratory Allergic symptoms Association Children
1. Introduction In recent years, more and more studies have observed that selfreported dampness in buildings is associated with an increase of respiratory illness, including cough, wheezing, airway infections and respiratory symptoms [1e7]. Multidisciplinary reviews have concluded that there are adverse health effects of dampness and mold in buildings, especially on asthma and allergies. In particular, dampness and odor at home might result in an increased risk of childhood asthma [8e11]. Building dampness, as an important public health issue, contributes to asthma and allergies among children in many geographical regions [12,13]. However, there are few studies and reports on the health effects of early-life exposure to home dampness, and the understanding about the influence of early-life exposure to dampness problems on health is insufficient, especially among children [14,15].
* Corresponding author. The College of Urban Construction and Environmental Engineering, Chongqing University, (Campus B), Chongqing, 400045, China. Tel: þ86 23 65127531, Fax: þ86 23 65127532. E-mail address: [email protected] (B. Li). http://dx.doi.org/10.1016/j.buildenv.2015.08.024 0360-1323/© 2015 Elsevier Ltd. All rights reserved.
China is a developing country under continued urbanization, and its morbidity rate of asthma among children under the age of 15 has increased sharply in recent years [16,17]. Rapid urbanization has caused much pressure on the indoor environment, which may contribute to the increase of asthma and related health problems. Studies in China have indicated that indoor environmental factors, including home dampness, may influence the prevalence of asthma and allergies among college students, school children and preschool children [18e21]. Chongqing is a city with high indoor relative humidity, low indoor wind speed and large rainfall all over the year which can increase the risk for pronounced dampness problems, and the higher asthma morbidity as compared to other cities in China [17,22e24]. Associations between exposure to dampness in residential buildings and health have already been studied in Chongqing recently [21]. However, there are no studies that have reported on exposure in early life and preschool children's health in Chongqing or other cities that have the same climate feature in China. Hence, the objective of this study is to assess whether early-life exposure to indoor dampness in homes is associated with the development of asthma, allergies and related symptoms among pre-school children in Chongqing, China.
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2. Material and methods
“Doctor-diagnosed asthma”: Has your child been diagnosed with asthma by a doctor? (yes vs. no)
This study is based on a cross-sectional questionnaire research in Chongqing, and carried out as the first phase of the study “China, Child, Homes, Health” (CCHH) [25]. Questionnaires were distributed to the parents of all 7177 children in randomly selected pre-schools in three different districts in Chongqing and were collected one week later by the teachers. The questionnaire survey has been carried out from December 2010 to April 2011.
“Doctor-diagnosed rhinitis”: Has your child been diagnosed with hay fever or allergic rhinitis by a doctor? (yes vs. no)
2.1. Questionnaire The questionnaire was adopted from a Swedish study on preschool children and was slightly modified for the consideration of Chinese conditions [1,18]. The questionnaire includes about 80 questions on demographic data, family conditions, dwelling characteristics, home dampness and health conditions of the child and the parent who answered the questionnaire [21,25]. This paper mainly focus on two parts: home dampness and health conditions of the child. The questionnaire asked some dampness problems of the entire resident environment in the perinatal period, and all questions on home dampness are as follows: “Current visible mold”: Have you noticed any visible mold on the floor, walls or ceiling in the child's room? (yes vs. no) “Current damp stains”: Have you noticed any visible damp stains on the floor, walls or ceiling in the child's room? (yes vs. no) “Current condensation on windows”: In the winter, did condensation or moisture occur on the inside or at the bottom of windows (windowpanes) in the child's room? (more than 25cm / 5-25cm / less than 5cm / no) “Current moldy odor”: Have you been bothered by moldy smell in your residence during the last 3 months? (frequently/ sometimes/ never) “Perinatal visible mold or damp stains”: When the child was born, have you noticed visible mold or damp stains on the floor, walls or ceiling? (frequently/ sometimes/ never) “Perinatal condensation on windows”: When the child was born, did condensation or moisture occur on the inside, at the bottom, of windows (windows) in the winter period? (frequently/ sometimes/ never) “Perinatal moldy odor”: When the child was born, have you been bothered by moldy smell in your residence? (frequently/ sometimes/ never) The questions on children's health covered respiratory and allergic symptoms in the last 12 months and doctor-diagnosed diseases, as follows: “Wheezing in the last 12months”: In the last 12 months, has your child had wheezing or whistling in the chest? (yes vs. no) “Cough at night in the last 12 months”: In the last 12 months, has your child had a dry cough at night for more than two weeks, apart from cough associated with a cold or chest infection? (yes vs. no) “Rhinitis in the last 12 months”: In the last 12 months, has your child had a problem with sneezing, or a runny, or a blocked nose when he / she did not have a cold or the flu? (yes vs. no) “Eczema in the last 12 months”: Has your child had eczema at any time in the last 12 months? (yes vs. no)
“Family history of asthma and allergies”: Does asthma or allergic diseases exist in the family? (yes vs. no) The answers were categorized into two groups: “Yes” (when the answer is “Frequently” or “Sometimes”) and “No” (when the answer is “Never”). The indicator “Condensation on windows” was classified in two categories: “Yes” (when the answer is “More than 25 cm”, “5e25 cm” and “less than 5 cm”) and “No” (when the answer is “no”). The answer “Don't know” was excluded from the analyses. A combined dampness indicator “Current visible mold or damp stains” was defined as “Yes” if visible mold or damp stains was noticed in the child's room, otherwise it was classified as “No”. Finally, home dampness includes three indicators: visible mold or damp stains, condensation on windows and moldy odor. Family history of asthma and allergies was classified as “Yes” if father, mother or siblings living in this house had asthma or allergic diseases and as “No” if none of them had these diseases. Exposure duration depends on the time when the exposure occurred. Perinatal exposure was defined as exposure occurred when the child was born, and current exposure is referring to the situation in the child's room when the questionnaire was answered. In order to evaluate the independent influence of perinatal-only exposure to dampness, all dampness indicators were classified into four categories according to the time when the dampness indicators were found by parents: “no exposure” (if neither perinatal nor current dampness indicators were reported), “perinatal-only exposure” (if only perinatal dampness indicators were reported), “current-only exposure” (if only current dampness indicators were reported) and “continuous exposure” (if both perinatal and current dampness indicators were reported). 2.2. Data analysis Statistical analysis was performed using the Statistical Package for Social Science (SPSS 18.0). Initially, associations were analyzed by chi-squared test for contingency tables. Then associations between home dampness indicators and health effects were calculated by multiple logistic regression, adjusting for gender of the child (boy vs. girl), age of the child (3 years vs. 4 years vs. 5 years vs. 6 years), family history of asthma or allergies (yes vs. no), environmental tobacco smoke exposure in uterus or during the first year of life (ETS exposure) (yes vs. no), gestation age (36 weeks vs. 37e40 weeks vs. 41 weeks) and house location (urban vs. rural or suburban). Adjusted odd ratio (AOR) with 95% confidence interval (CI) was calculated. P-value less than 0.05 indicated a statistically significant level. 2.3. Ethics statement The study complies with the Helsinki Declaration. The study and the consent procedure were approved by the Medical Research Ethics Committee of the School of Public Health, Fudan University. A written informed consent was obtained from the participants. 3. Results Among the selected 7117 children, 5299 children participated, and the response rate is 74.5%. One parent of each child answered the questionnaire. The study was limited to the child who has lived
H. Wang et al. / Building and Environment 94 (2015) 327e334
in the same house since birth and ranging from 3 to 6 years old. Questionnaires with missing information on the child's gender were excluded. Finally, 2917 questionnaires were included in this study. Tables 1e3 shows the prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by personal and family factors. The prevalence of wheezing and rhinitis in the last 12 months, doctor-diagnosed asthma and rhinitis was significantly higher among boys than girls. The prevalence of wheezing, cough at night and eczema in the last 12 months decreased with the increase of age, and it got the lowest value among the oldest children (6 years). The prevalence of asthma and allergic symptoms in the last 12 months and doctor-diagnosed asthma and rhinitis was more common for children with family history of asthma and allergies. Rhinitis in the last 12 months and doctor-diagnosed rhinitis was more common among children with ETS exposure, and eczema in the last 12 months was more common in children who were born early (gestation age 36 weeks). The prevalence of wheezing and rhinitis in the last 12 months, as well as doctordiagnosed asthma and rhinitis, was higher in urban as compared to rural/suburban areas. The child's gender and age, family history of asthma and allergies, ETS exposure, gestation age and house location were significantly associated with at least one of the asthma and allergic symptoms and thus these factors were included in the regression model as confounders. The prevalence of perinatal and current home dampness indicators is given in Table 4. The house location had significant influence on the prevalence of perinatal and current dampness problems. Visible mold or damp stains was more frequent in rural/ suburban as compared to urban areas (18.8% vs. 13.3% for perinatal exposure, 13.0% vs. 8.5% for current exposure). The condensation on windows was found more common in urban areas (15.4% vs. 9.4% for current exposure). The prevalence of moldy odor was reported higher in rural/suburban as compared to urban areas (15.9% vs. 10.7% for perinatal exposure, 14.5% vs. 10.6% for current exposure). Tables 5 and 6 shows the prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by perinatal and current dampness indicators. Higher rates of wheezing, cough at night and rhinitis in the last 12 months were found among children with perinatal or current exposure to home dampness. There was significantly more prevalence of eczema in the last 12 months when condensation on windows or moldy odor was noticed in the perinatal period. Children in homes with current or perinatal exposure to condensation on windows had more risk to be diagnosed with asthma and rhinitis by a doctor. In general, children in homes with perinatal or current dampness problems had more asthma and allergies and related symptoms.
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As a next step, associations were analyzed by multiple logistic regression models, adjusting for confounding factors, shown in Table 7. Wheezing in the last 12 months was significantly associated with exposure to dampness except current exposure to condensation on windows. The associations between cough at night in the last 12 months and all dampness indicators reported in perinatal period or currently were found. With perinatal exposure to dampness, the prevalence of rhinitis in last 12 months was significantly higher, and the risk of having rhinitis in the last 12 months was increased when current moldy odor was reported. Eczema in the last 12 months was significantly associated with perinatal condensation on windows and current visible mold or damp stains respectively. Perinatal exposure to moldy odor was a risk factor for doctor-diagnosed asthma, and the prevalence of doctor-diagnosed rhinitis was significantly influenced by perinatal and current condensation on windows. Respiratory and allergic symptoms in the last 12 months and doctor-diagnosed diseases reported by parents were strongly associated with most dampness indicators involved in this study. The strongest association in all results was found between perinatal exposure to moldy odor and wheezing in the last 12 months (AOR: 2.18; 95% CI: 1.65e2.88). The independent influence of perinatal exposure on children's health is present in Table 8, With no perinatal and current exposure as reference, perinatal-only exposure to dampness indicators was significantly associated with some the respiratory and allergic symptoms in the last 12 months, and perinatal-only exposure to condensation on windows was a risk factor for all symptoms involved in the study. The association between current-only exposure to condensation on windows and wheezing in the last 12 months was found and other associations between current-only exposure and respiratory and allergic symptoms in the last 12 months were not significant. The prevalence of respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night and rhinitis in the last 12 month, were significantly increased with continuous exposure (perinatal plus current exposure) to dampness while these associations were not found with current-only exposure. For doctor-diagnosed asthma, the prevalence was higher with perinatal-only exposure to moldy odor and continuous exposure to condensation on windows. The risk of doctor-diagnosed rhinitis reported by parents was significantly increased with perinatal-only, current-only and continuous exposure to condensation on windows, when using no exposure as reference. The independent influence on some respiratory and allergic symptoms in the last 12 months was significant with perinatal-only exposure to most dampness indicators, and in general the prevalence of these symptoms was further increased with continuous exposure. However, the significant influence of
Table 1 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by gender and age.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Total (n ¼ 2917)
Gender Boy (n ¼ 1467)
Girl (n ¼ 1450)
N (%)
N (%)
N (%)
303 (21.1) 265 (18.5)
262 (18.4) 263 (18.4)
588 199 156 106
533 188 98 78
565 (19.8) 528 (18.4) 1121 387 254 184
(39.0) (13.5) (8.9) (6.5)
(40.7) (13.8) (10.8) (7.4)
Age
(37.4) (13.3) (6.9) (5.5)
Pvalue
3 years (n ¼ 667)
4 years (n ¼ 952)
5 years (n ¼ 861)
6 years (n ¼ 437)
N (%)
N (%)
N (%)
N (%)
176 (19.0) 172 (18.5)
168 (19.8) 143 (16.9)
379 150 83 58
315 92 73 57
0.074 152 (23.2) 0.962 157 (23.9) 0.072 262 (39.6) 0.702 100 (15.3) <0.001 63 (9.6) 0.047 35 (5.4)
(40.5) (16.1) (8.9) (6.2)
(37.2) (10.8) (8.6) (6.8)
69 (16.2) 56 (13.1) 165 45 35 34
(38.4) (10.6) (8.2) (8.0)
Pvalue
0.035 <0.001 0.538 0.002 0.882 0.365
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in different gender and age groups were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between different gender and age groups, and bold represents the P-value less than 0.05.
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Table 2 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by personal and family factors. Family history of asthma and allergies
ETS exposure
Yes (n ¼ 322)
Yes (n ¼ 1498)
No (n ¼ 2515)
N (%)
Pvalue
N (%)
Wheezing in the last 12 months 108 (34.3) 93 (29.4) Cough at night in the last 12 months Rhinitis in the last 12 months 173 (54.7) Eczema in the last 12 months 57 (18.2) Doctor-diagnosed asthma 81 (25.6) Doctor-diagnosed rhinitis 53 (17.2)
N (%)
Gestation age No (n ¼ 1367)
P36 weeks value (n ¼ 146)
N (%)
N (%)
<0.001 309 (21.1) <0.001 282 (19.1)
247 (18.3) 240 (17.8)
0.059 29 (20.3) 0.364 35 (24.8)
369 (20.2) 342 (18.5)
153 (18.7) 138 (16.9)
0.669 0.078
924 324 170 128
<0.001 0.011 <0.001 <0.001
495 176 115 73
0.017 47 (32.6) 0.386 28 (19.6) 0.456 9 (6.4) 0.032 12 (8.3)
726 252 165 113
322 96 73 51
0.275 0.029 0.581 0.592
608 208 137 109
(41.1) (14.2) (9.3) (7.4)
N (%)
Pvalue
442 (17.8) 427 (17.2) (37.0) (13.0) (6.8) (5.1)
N (%)
41 weeks (n ¼ 834)
37e40 weeks (n ¼ 1868)
(36.7) (13.0) (8.5) (5.4)
(39.4) (13.8) (8.9) (6.2)
(39.2) (11.7) (8.9) (6.2)
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in different answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between different answers to each factor, and bold represents the P-value less than 0.05.
Table 3 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by house location. House location
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Rural/suburban (n ¼ 754)
Urban (n ¼ 2114)
N (%)
N (%)
171 131 246 106 50 32
389 387 854 274 202 149
(23.2) (17.8) (33.2) (14.5) (6.8) (4.4)
P-value
(18.7) (18.6) (41.0) (13.2) (9.7) (7.2)
0.009 0.606 <0.001 0.362 0.018 0.008
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Rural/Suburban” and “Urban” answers to house location were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Rural/Suburban” and “Urban” answers to each factor, and bold represents the Pvalue less than 0.05.
Table 4 Prevalence of dampness indicators at homes with different house locations. House location
Perinatal visible mold or damp stains Perinatal condensation on windows Perinatal moldy odor Current visible mold or damp stains Current condensation on windows Current moldy odor
Total (n ¼ 2868)
Rural/suburban (n ¼ 754)
Urban (n ¼ 2114)
N (%)
N (%)
N (%)
136 261 104 87 62 93
274 804 198 165 283 194
410 1065 302 252 345 287
(14.7) (38.5) (12.0) (9.6) (13.8) (11.6)
(18.8) (36.1) (15.9) (13.0) (9.4) (14.5)
P-value
<0.001 0.135 <0.001 0.001 <0.001 0.007
(13.3) (39.3) (10.7) (8.5) (15.4) (10.6)
1) N and % (within the parentheses) of responses of observed dampness indicators in different location of the houses were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on distributions of dampness indicators in different location of the houses, and bold represents the P-value less than 0.05.
Table 5 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by perinatal dampness indicators.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Perinatal visible mold or damp stains
Perinatal condensation on windows
Perinatal moldy odor
Yes
No
Yes
No
Yes
No
N (%)
N (%)
N (%)
N (%)
N (%)
N (%)
125 104 183 55 42 30
420 410 916 323 207 148
253 235 467 168 110 86
292 276 618 210 136 89
96 82 137 46 37 17
388 380 840 278 176 137
(30.3) (25.4) (44.3) (13.5) (10.3) (7.4)
P-value
(17.8) (17.3) (38.5) (13.6) (8.7) (6.2)
<0.001 <0.001 0.025 0.967 0.297 0.375
(23.8) (22.1) (43.6) (15.8) (10.3) (8.1)
P-value
(17.2) (16.2) (36.1) (12.3) (8.0) (5.2)
<0.001 <0.001 <0.001 0.009 0.034 0.002
(32.0) (27.2) (45.2) (15.3) (12.4) (5.6)
P-value
(17.5) (17.1) (37.8) (12.5) (7.9) (6.2)
<0.001 <0.001 0.013 0.165 0.009 0.718
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Yes” and “No” answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Yes” and “No” answers to each indicator, and bold represents the P-value less than 0.05.
H. Wang et al. / Building and Environment 94 (2015) 327e334
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Table 6 Prevalence of respiratory and allergic symptoms and doctor-diagnosed diseases stratified by current dampness indicators.
Wheezing in the last 12 months Cough at night in the last 12 months Rhinitis in the last 12 months Eczema in the last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Current visible mold or damp stains
Current condensation on windows
Current moldy odor
Yes
Yes
Yes
No
P-value
N (%)
N (%)
74 67 108 46 31 21
421 415 908 314 199 141
(29.8) (27.2) (43.20 (18.7) (12.5) (8.6)
<0.001 <0.001 0.128 0.018 0.029 0.105
(17.8) (17.5) (38.3) (13.2) (8.4) (5.9)
No
P-value
N (%)
N (%)
75 94 150 53 44 34
422 356 804 283 181 123
(21.9) (27.4) (43.6) (15.4) (12.8) (10.0)
(19.7) (16.6) (37.3) (13.2) (8.4) (5.7)
0.339 <0.001 0.024 0.262 0.008 0.003
No
P-value
N (%)
N (%)
88 74 138 43 36 20
386 374 817 277 172 130
(30.9) (25.7) (48.3) (15.0) (12.6) (7.1)
(17.6) (17.0) (37.2) (12.6) (7.8) (5.9)
<0.001 <0.001 <0.001 0.243 0.006 0.438
1) N and % (within the parentheses) of responses on reported cases of respiratory and allergic symptoms and doctor-diagnosed diseases in “Yes” and “No” answers to each factor were calculated when the missing data was excluded. 2) P-value was calculated by chi-squared test on prevalence of asthma and allergies between “Yes” and “No” answers to each indicator, and bold represents the P-value less than 0.05.
Table 7 Associations between perinatal exposure to dampness and health effects by adjusted odds ratio (AOR) with 95% confidence interval (95% CI).
Wheezing last 12 months Cough at night last 12 months Rhinitis last 12 months Eczema last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Perinatal visible mold or damp stains
Perinatal condensation on windows
Perinatal moldy Current visible mold or damp Current condensation on odor stains now windows now
Current moldy odor
1.90 (1.48,2.43)
1.44 (1.18,1.75)
2.18 (1.65,2.88) 1.75 (1.28,2.38)
1.11 (0.83,1.49)
1.93 (1.44,2.57)
1.56 (1.20,2.02)
1.42 (1.16,1.73)
1.87 (1.40,2.50) 1.64 (1.20,2.25)
1.79 (1.36,2.35)
1.65 (1.22,2.22)
1.25 (1.00,1.56)
1.29 (1.10,1.52)
1.39 (1.08,1.79) 1.21 (0.92,1.60)
1.22 (0.96,1.55)
1.54 (1.19,2.00)
0.97 (0.70,1.33)
1.36 (1.09,1.71)
1.30 (0.92,1.84) 1.43(1.00,2.04)
1.22 (0.88,1.69)
1.25 (0.87,1.79)
1.05 (0.72,1.53)
1.16 (0.88,1.53)
1.56 (1.05,2.33) 1.28 (0.83,1.99)
1.41 (0.97,2.06)
1.43 (0.94,2.17)
1.22 (0.80,1.86)
1.51 (1.10,2.09)
0.90 (0.53,1.53) 1.47 (0.89,2.42)
1.76 (1.16,2.68)
1.08 (0.65,1.81)
1) Adjustments were made for gender, age, family history of asthma and allergies, ETS exposure, gestation age and house location. 2) Adjusted odds ratio (AOR) was estimated for dampness indicators with “Yes” answer compared with “No” answer. The AOR of dampness indicators with “No” answer is 1, and bold represents the P-value less than 0.05.
Table 8 Associations between exposure to dampness and health effects by adjusted odds ratio (AOR) with 95% confidence interval (95% CI). Visible mold or damp stains Perinatal-only Wheezing last 12 months Cough at night last 12 months Rhinitis last 12 months Eczema last 12 months Doctor-diagnosed asthma Doctor-diagnosed rhinitis
Current-only
Condensation on windows Continuous
Perinatal-only
Current-only
Moldy odor Continuous
Perinatal-only
Current-only
Continuous
1.84 (1.34,2.52) 1.34 (0.84,2.15) 2.35 (1.51,3.66) 1.63 (1.30,2.06) 1.82 (1.03,3.21) 1.22 (0.87,1.72) 1.89 (1.26,2.82) 1.31 (0.84,2.05) 2.64 (1.80,3.88) 1.54 (1.10,2.14) 1.50 (0.95,2.38) 1.85 (1.16,2.95) 1.34 (1.05,1.72) 1.61 (0.89,2.93) 1.95 (1.42,2.67) 1.55 (1.02,2.37) 1.07 (0.67,1.72) 2.45 (1.66,3.62) 1.40 (1.06,1.85) 1.20 (0.81,1.79) 1.12 (0.74,1.71) 1.27 (1.04,1.54) 0.91 (0.54,1.55) 1.44 (1.10,1.89) 1.20 (0.83,1.73) 1.27 (0.88,1.85) 1.84 (1.29,2.64) 0.95 (0.63,1.43) 1.50 (0.91,2.47) 1.37 (0.81,2.35) 1.67 (1.28,2.19) 1.76 (0.92,3.38) 1.40 (0.96,2.05) 1.06 (0.63,1.78) 0.86 (0.48,1.53) 1.52 (0.95,2.43) 0.83 (0.49,1.40) 1.21 (0.65,2.26) 1.08 (0.54,2.18) 1.01 (0.72,1.43) 0.88 (0.34,2.29) 1.58 (1.04,2.40) 1.83 (1.06,3.14) 1.17 (0.62,2.21) 1.69 (0.96,2.99) 1.02 (0.57,1.82) 1.50 (0.75,3.01) 1.50 (0.72,3.13) 1.76 (1.19,2.60) 2.37 (1.02,5.49) 2.01 (1.21,3.34) 0.77 (0.35,1.73) 1.05 (0.51,2.17) 1.09 (0.53,2.25)
1) Adjustments were made for gender, age, family history of asthma and allergies, ETS exposure, gestation age and house location. 2) Adjusted odds ratio (AOR) was estimated for dampness indicators with no exposure as reference and the AOR was 1, and bold represents the P-value less than 0.05.
perinatal-only exposure was less consistently found on the doctordiagnosed diseases, and few associations between current-only exposure and health outcomes were found as compared to no exposure. 4. Discussion As most epidemiological studies, this study used subjective reports for the assessment of the associations between dampness exposure and health outcomes. Selection bias, non-response bias, recall bias and confounders could influence the results [11,26,27]. In this study, Cluster random sampling used in this study and high
response rate indicated that the impact of selection bias was limited. Non-response bias was evaluated by re-inviting initial respondents to complete a short questionnaire, and there were no significant differences in the same questions between 5299 responders and 206 non-respondents [21]. Recall bias was inevitable when all information was collected through participant reports via questionnaire [27]. Participants were asked about the dampness problems at the perinatal period and currently, so respondents were likely to have forgotten about their exposures in earlier period. Large sample size and accurate and clear questions designed could reduce the influence of recall bias to a certain extent. Respondents might recall a prior exposure differently
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depending on their children's disease status, and perinatal exposure to dampness would be over-reported by parents with current exposure [27]. Some studies take objective inspections to measure dampness and make comparison with the results of self-reported questionnaire, and most similar studies have shown that occupants reported more dampness problems, while there are some studies where the occupants have reported less dampness than inspectors [8,28,29]. The associations between observation on dampness made by inspector and health effects are also different from that between parental-reported dampness and illness [8,30]. In this study, the results could be susceptible to subjectivity from investigator, and the associations could be over-estimated. So, the possible impact on associations would be considered with appropriate data analysis and comparison of results in previous study to eliminate the influence of recall bias as much as possible. Confounding factors were also considered in this study. Residential characteristics and human behavioral habit would improve or deteriorate indoor dampness conditions [18]. In order to avoid the influence of residential characteristics and human behavioral habits on the results, stratified analysis was performed in this study. Finally, with the common confounders, such as gender of the child, age of the child, family history of asthma or allergies, environmental tobacco smoke exposure in uterus or during the first year of life, gestation age, house location were included in the logistic regression model as a confounding factor and other variables were found not to meet the criteria of a confounder [21,27,31]. Thus, the impact of confounders on the results was greatly reduced. Dampness is a generic term and there has been little to no substantive progress in defining what “dampness” is [32]. In this study, dampness is overall condition of moisture in buildings and is defined as presence of three indicators: visible mold or damp stains, condensation on windows and moldy odor. The purpose of this paper is to evaluate the influence of early-life exposure to dampness on children's asthma, allergies and related symptoms, and all the data about dampness and health were self-reported via questionnaire. Visible mold, damp stains and moldy odor are common indicators in previous studies [2,7,8,15]. Condensation on windows is not considered generally especially in early-life exposure, however condensation could cause microbial growth and chemical process, e.g. mite and irritant substances and/or allergens, that may influence children's health [1,8]. In Chongqing, high indoor relative humidity (the relative humidity is greater than 70% in most of the year, and in winter the percentage of time with relative humidity above 70% was 94%), and low indoor wind speed (the annual average wind speed is about 0.107 m/s, and the average wind speed is about 0.087 m/s in winter) may result in condensation on windows [22e24]. Thus, condensation on windows, as dampness indicator, was added in this study to evaluate the health effects of dampness, and these three indicators could effectively represent the severity of dampness in buildings. In this study, perinatal exposures were considered as early-life exposures, and the health effects were divided into two parts: respiratory and allergic symptoms in the last 12 months (wheezing, cough at night, rhinitis and eczema in the last 12 months) and doctor-diagnosed diseases (doctor-diagnosed asthma and rhinitis). In order to evaluate the independent health effects of perinatalonly exposure to dampness, exposure to home dampness was divided into four categories and the category “no perinatal and current exposure” was taken as reference in the regression model, and the results of perinatal-only exposure with no exposure and continuous exposure (perinatal plus current exposure) with current-only exposure were compared. Because the respondents were likely to more prone to remember and report their past exposure in the perinatal period when the current exposure was found, and comparison as described above may effectively reduce
the influence of recall bias to accurately evaluate the independent health effects of perinatal-only exposure. In this study, perinatal-only exposure to dampness problems was found to be associated with respiratory and allergic symptoms in the last 12 months whether current exposure was reported by the parents or not. The risk of wheezing and cough at night in the last 12 months was generally higher with perinatal-only exposure as compared to no exposure, and it was consistent with the findings of similar studies [7,15,33e35]. The prevalence of rhinitis and eczema in the last 12 months was strongly related with perinatalonly exposure to visible mold or damp stains and condensation on windows. The results were in agreement with previous studies that have observed that the risk of self-reported allergic rhinitis and eczema among children was increased when exposed to visible mold and dampness in the early period of child growth, and few associations with condensation on windows was reported [2,15,36]. For influence of early-life exposure to dampness on respiratory and allergic symptoms, similar associations have been found by other studies as well [37e39]. Meanwhile, the prevalence of respiratory and allergic symptoms was further increased with continuous exposure, and these symptoms were more strongly related to dampness indicators when exposed in both the perinatal period and currently. This is in accordance with an Italian study [2]. All symptoms included in this study were in the last 12 months, and it was shown that early-life exposure to perinatal dampness could significantly influence the prevalence of some current respiratory and allergic symptoms, consistent with recent reports [2,15]. Thus, early-life exposure to perinatal dampness was strongly related with some current respiratory and allergic symptoms, and when both perinatal and current exposure was reported the risk could be further increased, while almost no such increase with current-only exposure was observed. For doctor-diagnosed diseases, there was less association found in this study. Condensation on windows was found as a risk factor for doctor-diagnosed rhinitis, and doctor-diagnosed asthma was associated with perinatal-only exposure to condensation on windows and moldy odor. It was shown in a Swedish cross-sectional study that self-reported current exposure to condensation on windows was significantly associated with doctor-diagnosed asthma and rhinitis [1]. However, few strong associations between self-reported condensation on windows and moldy odor in early phase of developmental stage and doctor-diagnosed asthma/ rhinitis have been found in similar studies [2,8,32]. Recent studies that used quantitative measures of indoor dampness, including professional inspections, did not find associations between doctordiagnosed asthma/allergy in children and different indexes of indoor dampness [32,40]. So, it is possible that recall bias is a explanation for the associations, and these associations involving doctor-diagnosed diseases should be further identified in following study, especially with quantitative method for assessing risk of dampness exposure. It is, however, to be noted that there are still unclear mechanisms for the associations between dampness problems and asthma, allergies and some other related symptoms. The most possible evidence includes the associations of microbial toxins and health effects in damp environment of Chongqing. However, the evidence is very limited to prove this [41,42]. According to previous studies, microbes were reported to be detected in typically moisture damaged environment [43,44]. Under the humid climate, the microbial toxins are able to exist for a long time, and may have influence on children's health in the long run. However, specific causative agents have not been established, and there are so many studies that have showed that the health effects associated with dampness cannot be explained by a single mechanism [11]. The age of having asthma, allergies and related symptoms and
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the development after getting similar health problems is not included in this study, so more studies are needed to take them into account to further identify specific health effects with exposure to dampness in different developmental stages among children. However, the initial results of the study suggest that to protect the child from dampness environment could reduce the adverse impact on children's health. Another limitation of this study is that all data on exposure and health effects were obtained using questionnaire. There are limitations on the possibility to draw conclusions on causality, and recall bias may lead to over-estimation of the true effects of subjectivity from respondents. Following studies to indentify the casual relationship between dampness and health effects should be assessed with quantitative techniques. 5. Conclusions In Chongqing, early-life exposures to home dampness in perinatal period were strongly associated with some respiratory and allergic symptoms in the last 12 month among children. The prevalence of respiratory and allergic symptoms in the last 12 months, including wheezing, cough at night, rhinitis and eczema, was significantly increased with perinatal-only exposure to most dampness indicators, and was further increased with continuous exposure. There was no such increase of these symptoms with current-only exposure. The associations between doctor-diagnosed asthma/rhinitis and perinatal-only exposure to condensation on windows and moldy odor were found, and these associations should be further identified due to the impact of recall bias. Selfreported perinatal exposure to home dampness had adverse health effects and was a risk factor for some current respiratory and allergic symptoms in the last 12 months. So, early-exposure to dampness problems should receive more attention and the improvement of indoor environment is needed to avoid dampness environment in buildings, especially in the early period of children's growth. Following studies should focus on the causal relationship between home dampness and health effects and the mechanism of health effects related to dampness problems using objective metric for dampness and related problems. Acknowledge The study has been supported by the National Technology Support Project (2012BAJ02B06), the 111 Project (No.B13041), and “the Short-term International Academic fund” of Chongqing University 2015 Overseas Visiting Student Project (No. GJXSFX150210). References [1] C.G. Bornehag, J. Sundell, L. Hagerhad-Engman, T. Sigsggard, S. Janson, N. Aberg, et al., ‘Dampness’ at home and its association with airway, nose, and skin symptoms among 10,851 preschool children in Sweden: a cross-sectional study, Indoor Air 15 (Suppl. 10) (2005) 48e55. [2] M. Simoni, E. Lombardi, G. Berti, F. Rusconi, Piffer S. GruttanSL, et al., Mould/ dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study, Occup. Environ. Med. 62 (9) (2005) 616e622. [3] S.H. Cho, T. Reponen, G. LeMasters, L. Levin, J. Huang, T. Meklin, et al., Mold damage in homes and wheezing in infants, Ann. Allerg. Asthma Im. 97 (4) (2006) 539e545. [4] K.W. Tham, M.S. Zuraimi, D. Koh, F.T. Chew, P.L. Ooi, Associations between home dampness and presence of molds with asthma and allergy symptoms among young children in the tropics, Pediatr. Allergy Immunol. 18 (5) (2007) 418e424. [5] T. Antova, S. Pattenden, B. Brunekreef, J. Heinrich, P. Rudnai, F. Forastiere, H. Luttmann-Gibson, L. Grize, B. Katsnelson, H. Moshammer, B. Nikiforov, H. Slachtova, K. Slotova, R. Zlotkowska, T. Fletcher, Exposure to indoor mould and children's respiratory health in the PATY study, J. Epidemiol. Community Health 62 (8) (2008) 708e714. [6] R. Pirastu, C.P. Bellu, U. Pelosi, R. Pistelli, G. Accetta, A. Biggeri, Indoor exposure to environmental tobacco smoke and dampness: respiratory symptoms in
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