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House dust mites produce well-known allergens for asthma and allergy among children. To study house dust mite allergen exposure level in northeast China and characterize its association with indoor environmental factors and cleaning habits, we inspected 399 homes in Tianjin area and collected dust from mattresses. Dermatophagoides farinae (Der f) and Dermatophagoides pteronyssinus (Der p) were detected by the enzyme-linked immunosorbent assay (ELISA) method. The medians of total allergen concentrations for spring, summer, autumn, and winter were 524 ng/g, 351 ng/g, 1022 ng/g, and 1010 ng/g. High indoor air relative humidity (RH), low air change rate, indoor dampness, and frequent changing of quilt cover/bedsheet/pillow case were significantly associated with high house dust mite allergen concentration (relative risk [RR]: RH, 1.18-1.34; air change rate, 0.97-1.00; dampness, 2.92-3.83; changing quilt cover/bedsheet/pillow case, 0.66-0.75). The decrease in the absolute humidity gradient between indoors and outdoors that occurs with increased air change rate may explain why a high ventilation reduces house dust mite allergen concentration. The findings of this study show the importance of ventilation and cleaning for controlling house dust mite allergens. We found that the decrease in additional absolute humidity (e.g., humidity (indoor)-humidity (outdoor)) with increased air change rate may be the main reason that a high ventilation rate reduces house dust mite allergen concentration. Ventilation and cleaning should be both considered for creating a healthy home environment.

A questionnaire survey on dermal symptoms and home environment was performed in eight Chinese cities (40 279 participants). Data on city level temperature, precipitation, PM10 , NO2, and gross domestic product (GDP) per capita were collected. In total, 2.2% had eczema, 2.4% facial erythema (FE) and 2.6% seborrheic dermatitis symptoms (SD). Higher temperature was associated with eczema (OR = 1.09). Higher GDP per capita was related to less SD. Higher PM10 was related to SD. Suburban living was protective for eczema (OR = 0.77) (vs. urban). Living in old buildings (built before 1991) was related to eczema (OR = 1.42). Living near heavily trafficked roads was related to FE (OR = 1.33) and SD (OR = 1.35). Having new furniture was related to all symptoms (OR = 1.26-1.47). Burning mosquito coils (OR = 1.37-1.57) and incense (OR = 1.33-1.37) were associated with eczema, FE, or SD. Presence of cockroaches and rats/mice was associated with FE or SD (OR = 1.31-1.40). Using air conditioner, daily cleaning and frequently exposing bedding to sunshine were protective (OR = 0.60-0.83). In conclusion, higher temperature, higher PM10 , urban living, living near heavily trafficked roads, old buildings, new furniture, burning mosquito coils and incense, and presence of cockroaches/rats/mice increased the risk of eczema, FE, or SD. Higher GDP, air conditioner, daily cleaning, and exposing bedding to sunshine were protective.

We investigated associations between prenatal and postnatal environmental factors and onset and remission of preschool childhood eczema across China. The study population was preschoolers in randomized day care centers in seven cities (N = 39,782). Data on eczema and prenatal and postnatal indoor and outdoor environment were obtained from a cross-sectional questionnaire sent to parents or other guardians. Reports on eczema in the first 2 years and in the past year was used to retrospectively calculate onset and remission (changes of reported eczema). Prenatal and postnatal outdoor temperature, NO2 and PM10 were modelled from official air pollution data. Associations were estimated by two-level logistic regression. Calculated onset rate was 3.2%/y and remission rate 29.2%/y. Exposure to NO2 during pregnancy was associated with onset of eczema, similarly for all trimesters. Postnatal PM10 and NO2 were related to decreased remission. Postnatal outdoor temperature was associated with onset of eczema. Pre-natal and current redecoration or buying new furniture, and perinatal as well as current dampness and indoor mould, were associated with increased onset and decreased remission. Cockroaches in current home was another indoor risk factors. Prenatal exposure to farm environment and large family size were all negatively associated with eczema. In conclusion, a warmer climate and prenatal NO2 can be associated with increased onset of eczema in Chinese preschoolers. Postnatal PM10 and NO2 can be associated with reduced remission. Perinatal and current dampness, indoor mould and cockroaches may increase onset and decrease remission. Exposure to chemical emissions from indoor materials after first year of life may increase onset. Prenatal exposure to farm environment and large family size could be protective.

We estimated associations between ambient air pollution, home environment and asthma as well as rhinitis among adults across China. A total of 40,279 young adults from eight Chinese cities participated in a questionnaire survey (participation rate 75%). There were questions on health and home environment. Information on city level gross domestic product (GDP) per capita, ambient temperature and PM10 and NO2 were collected from registers. Two-level logistic regression models were used to study health associations. Totally 1.6% reported asthma and 6.6% reported allergic rhinitis (AR). Higher temperature was associated with more asthma but less AR. Higher GDP was associated with less asthma but more AR. Higher degree of urbanization, higher level of NO2 and living near heavily trafficked road were risk factors for asthma and AR. Participants in older buildings reported more asthma. Redecoration and buying new furniture were related to more asthma and AR (OR = 1.15-1.91). Using natural gas (OR = 1.34) and biomass (OR = 1.35) for cooking were risk factors for AR. Burning mosquito coils and incense increased the risk of asthma and AR. Cat keeping (OR = 2.88), dog keeping (OR = 2.04), cockroaches (OR = 1.54) and rats or mice (OR = 1.46) were associated with asthma. Cockroaches increased the risk of AR (OR = 1.22). Air humidifier and air cleaner were linked to asthma and AR. Frequent cleaning and exposing bedding to sunshine were protective. In conclusion, urbanization, NO2 and traffic exhaust can increase the risk of adult asthma and AR. Higher ambient temperature was related to more asthma but less AR. Indoor animals such as cats, dogs, rats/mice and presence of cockroaches were associated with asthma or AR. Indoor chemical sources such as redecoration and new furniture were other risk factors. Cooking with natural gas or biomass and burning mosquito coils and incense were associated with asthma or AR. Frequent cleaning and exposing bedding to sunshine were protective.

This paper studied associations between reported common cold and home dampness and mould, cleaning habits and ventilation, climate and outdoor air pollution in China among young adults without asthma or allergic rhinitis. Parents of children attending day care in eight Chinese cities answered a questionnaire on their health and home environment (75% response rate). We restricted the population to subject without asthma or allergic rhinitis (N = 37,275). Temperature and air pollution data was obtained from monitoring stations. Associations were estimated by multilevel logistic regression. Totally 12.5% reported common cold (≥3 colds) and 1.6% frequent common cold (≥5 colds) in the past 12 months. Female gender (OR = 1.53; 95% CI 1.37–1.71), residents in southern China (OR = 1.89; 95% CI 1.16–3.07) and living in homes with water leakage (OR = 1.32; 95% CI 1.16–1.50), mould odour (OR = 1.48; 95% CI 1.28–1.72), indoor mould (OR = 1.47; 95% CI 1.28–1.70), condensation on window panes (OR = 1.42; 95% CI 1.32–1.52) and damp bed clothing (OR = 1.19; 95% CI 1.11–1.28) were associated with common cold. Having many signs of dampness increased ORs. Daily cleaning (OR = 0.91; 95% CI 0.85–0.97) and mechanical ventilation in kitchen or bathroom (OR = 0.75; 95% CI 0.64–0.89) were protective. Higher mean ambient temperature (OR = 1.11 per °C; 95% CI 1.02–1.21), PM10 (OR = 1.17 per 10 μg/m3 ; 95% CI 1.14–1.21) and PM2.5 (OR = 1.28 per 10 μg/m3 ; 95% CI 1.20–1.37) were associated with common cold. The association with particulate air pollution was stronger in southern China. Similar associations were found for frequent common cold. In conclusion, indoor dampness and mould, a warmer climate and PM10 and PM2.5 can be associated with reported common cold. Further intervention and prospective studies are needed to verify causality of observed association in this cross-sectional study.

Few studies exist from China on associations between home environment and adult health. We studied associations between home environment factors (other than dampness and mould) and rhinitis, throat and dermal symptoms and headache and fatigue among young parents in six cities across China (N = 36,541). They were recruited as parents from day care centers selected randomly and answered a questionnaire on medical symptoms and the home environment. Odds ratios (OR) were calculated by multilevel logistic regression adjusting for gender, atopy, smoking, home size and dampness/mould. Overall, 4.8% had skin symptoms 3.1% rhinitis, 2.8% eye, 4.1% throat symptoms, 3.0% headache and 13.9% had fatigue (all as weekly symptoms). Redecoration was associated with rhinitis, eye and skin symptoms, headache and fatigue. New furniture was associated with eye, throat and skin symptoms and fatigue. Gas cooking was associated with eye and throat symptoms, headache and fatigue. Biomass cooking was associated with eye and throat symptoms and headache. Burning incense was associated with eye, throat and skin symptoms, headache and fatigue. Presence of cockroaches and mosquitos or flies was associated with all six symptoms. Rats or mice were associated with eye and dermal symptoms. Cat keeping was associated with eye symptoms while dog keepers had less fatigue. Living near major roads was associated with rhinitis, eye, throat and skin symptoms and fatigue. Daily cleaning, a mechanical ventilation system in the kitchen or in the bathroom, living in older buildings and living in less urbanized areas were protective factors. In conclusion, urbanization, traffic exhaust, indoor emissions from redecoration and new furniture, gas cooking and air pollution from burning incense and biomass may cause dermal and mucosal symptoms, headache and fatigue among adults in China. Indoor animals (cats, mice/rats, cockroaches) were other risk factors. Daily cleaning, mechanical ventilation and living in older

The main aim was to study associations between asthma, allergic rhinitis and eczema among adults across China and dampness and mold at home. Young adults (N = 40,279) in eight cities in China answered a questionnaire in 2010-2012 (response rate 75.0%). Data on asthma, allergic rhinitis, eczema and the home environment was assessed by the questionnaire. Climate data was obtained from China Meteorological Administration and the website of Weather Underground. Health associations were analyzed by two-level logistic regression models, adjusting for covariates. Totally 1.6% had asthma, 6.6% allergic rhinitis and 2.2% eczema. Mold odor was associated with asthma (OR = 1.90) and allergic rhinitis (OR = 1.25-1.44). Window pane condensation in winter was associated with asthma (OR = 1.39), allergic rhinitis (OR = 1.26-1.58) and eczema (OR = 1.36-1.77). Presence of mold spots or damp stains was related to asthma (OR = 1.58-2.49), allergic rhinitis (OR = 1.35-1.76) and eczema (OR = 1.47-1.70). Water damage was related to asthma (OR = 1.69-1.82), allergic rhinitis (OR = 1.40-1.45) and eczema (OR = 1.44-1.96). Damp bed clothing was related to asthma (OR = 1.23), allergic rhinitis (OR = 1.23) and eczema (OR = 1.35). A higher dampness score was associated with increased odds ratios for diseases. Those living in older buildings had more asthma (OR = 1.39-1.76) and allergic rhinitis (OR = 1.16-1.21). Those living in suburban or rural areas had less asthma, allergic rhinitis and eczema as compared to those living in urban areas (OR values from 0.24 to 0.66). Stronger health associations with dampness and mold were found in southern China and in newer buildings (constructed after 2005). In conclusion, dampness and mold at home can be risk factors for asthma, allergic rhinitis and eczema among adults in China. Living in older buildings can be risk factors for asthma or allergic rhinitis while living in less urbanized areas can be protective.

During 2010-2012, we conducted an observational study on household environment and health outcomes among 40,010 preschool children from seven cities of China. Here we examined associations of six dampness-related indicators (visible mold spots, visible damp stains, damp clothing and/or bedding, water damage, condensation on windowpane, moldy odor) in the current residence and three dampness-related indicators (visible mold spots, condensation on windowpane, moldy odor) in the early residence with childhood asthma and rhinitis. In the multi-level logistic regression analyses, visible mold spots and visible damp stains in the current residence were significantly associated with the increased odds of doctor-diagnosed asthma and allergic rhinitis during lifetime-ever (adjusted odd ratios (AORs) range: 1.18-1.35). All dampness-related indicators were significantly associated with increased odds of wheeze and rhinitis during lifetime-ever and in the past 12 months (AORs range: 1.16-2.64). The cumulative numbers of damp indicators had positively dose-response relationships with the increased odds of the studied diseases. These associations for wheeze and rhinitis were similar between northern children and southern children. Similar results were found in the sensitive analyses among children without a family history of allergies and among children without asthma and allergic rhinitis. For 3-6 years-old children in mainland of China in 2011, we speculated that about 90,000 (2.02%) children with asthma and about 59,000 (1.09%) children with allergic rhinitis could be attributable to exposing to visible mold spots in the current residence. Our results suggested that early and lifetime exposures to household dampness indicators are risk factors for childhood asthma and rhinitis.

From October 2010 to April 2012, we conducted a cross-sectional study of associations between household environments and childhood health among preschool children in eight Chinese cities. Here, we analyze associations of early household renovation with preterm birth (PTB), low birthweight (LBW), term low birthweight (Term-LBW), and small for gestational age (SGA). Parents responded to questions about household renovation and their children's gestational age and birthweight. In the multivariate logistic regression analyses, household renovation in the year before pregnancy was significantly associated with LBW (sample size: N = 25 813; adjusted odds ratio (OR) with 95% confidence intervals (CIs): 1.23, 1.01-1.50) and Term-LBW (N = 24 823; 1.29, 1.01-1.67). Household renovation during pregnancy was significantly associated with PTB (N = 25 202; 1.28, 1.01-1.69). These significant associations were also found in the two-level (city-child) logistic regression analyses and in the sensitivity analyses among 21 009 children with complete data in all studied variates. Stronger associations were found in certain subgroups. Our findings indicate that household renovation within one year before pregnancy might be a risk factor for LBW and Term-LBW, while household renovation during pregnancy could be a risk factor for PTB.

We studied indoor sources of indoor particulate matter (PM), outdoor air pollution and antibiotic use in relation to asthma, rhinitis and eczema among pre-school children and investigated synergistic effects between PM and antibiotics use. Children (3-6y) from randomly selected day care centres in seven cities across China were included (n = 39,782). Data on ambient temperature and air pollution were collected from local monitoring stations. Data on indoor PM sources (ETS, burning of incense or mosquito coils and biomass for cooking), antibiotics use and health (doctor diagnosed asthma and rhinitis, lifetime eczema, current wheeze and current rhinitis) were assessed by a parental questionnaire. Associations were calculated by multilevel logistic regression. Asthma diagnosis was associated with outdoor temperature, NO2 and burning mosquito coils. Rhinitis diagnosis was associated with NO2, ETS, gas cooking and burning biomass for cooking. Lifetime eczema was associated with temperature, PM10, NO2, ETS, biomass cooking and burning mosquito coils. Burning incense was associated with current wheeze and current rhinitis. Children using antibiotics had more asthma, wheeze, rhinitis, and eczema. Excluding children with respiratory infections did not change associations with antibiotics use. Antibiotics use enhanced the effects of ETS and PM10 (a synergistic effect). In conclusion, a warmer climate, outdoor NO2 and PM10, ETS, gas cooking and burning biomass, incense and mosquito coils can increase the risk of asthma, wheeze, rhinitis and eczema among pre-school children in China. Antibiotics use is a risk factor for childhood asthma, wheeze, rhinitis and eczema and ETS and outdoor PM10 can enhance the effect., De 2 första författarna delar förstaförfattarskapet.