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Common cold is usually considered to be associated with outdoor climate, but the evidence linking with indoor environmental factors is lacking. The role of indoor renovations during which critical timing window on childhood common cold remains unclear. Therefore, we investigated the effect of exposure to new furniture and/or redecoration during prenatal and postnatal periods on the occurrence and duration of common cold in preschool children. We conducted a retrospective cohort study of 39 782 children aged 3–6 years in seven cities of China. The occurrence and duration of common cold in children, and their lifetime exposures to indoor new furniture and redecoration (including pregnancy, the first year of life, and after one year old) were assessed using a questionnaire administered by the parents. Associations between high frequency (>5 colds) and long duration (≥2 weeks per cold) of common cold during past 12 months and exposure to indoor new furniture/redecoration were examined by logistic regression models in terms of odds ratio (OR) and 95% confidence interval (CI). We found that the prevalence of high frequency and long duration of common cold in preschool children in China were, respectively, 9.2% and 11.9%. Frequent common cold was significantly associated with exposure to indoor new furniture/redecoration during pregnancy, first year, and after 1 year old, respectively, with the ORs (95% CI) = 1.25 (1.12–1.39), 1.11 (1.00–1.25), and 1.09 (1.01–1.18). Furthermore, childhood long duration per cold was associated with exposure to indoor new furniture/redecoration during pregnancy with OR (95% CI) of 1.14 (1.03–1.25) but not with postnatal exposure. We identified that prenatal exposure to home renovation was more critical than postnatal exposure for an increased risk of high frequency and long duration of common cold. Sensitivity analysis showed that the association between prenatal exposure to indoor renovations and the risk of childhood common cold was consistent and robust, and the associations were modified by some personal and indoor environmental factors. Our findings indicated that prenatal and postnatal exposure to home renovation played an important role in the risk of childhood common cold, supporting the hypothesis of "fetal origin of childhood infection." [ABSTRACT FROM AUTHOR]

Increasing studies linked outdoor air pollution (OAP), indoor environmental factors (IEFs), and antibiotics use (AU) with the first wave of allergies (i.e., asthma, allergic rhinitis, and eczema), yet the role of their exposures on children's second wave of allergy (i.e., food allergy) are unknown. To investigate the association between exposure to OAP and IEFs and childhood doctor-diagnosed food allergy (DFA) during the pre-pregnancy, prenatal, early postnatal, and current periods, and to further explore the effect of OAP and IEFs on DFA in children co-exposed to antibiotics. A retrospective cohort study involving 8689 preschoolers was carried out in Changsha, China. Data on the health outcomes, antibiotic use, and home environment of each child were collected through a questionnaire. Temperature and air pollutants data were obtained from 8 and 10 monitoring stations in Changsha, respectively. Exposure levels to temperature and air pollutants at individual home addresses were calculated by the inverse distance weighted (IDW) method. Multiple logistic regression models were employed to assess the associations of childhood DFA with exposure to OAP, IEF, and AU. Childhood ever doctor-diagnosed food allergy (DFA) was linked to postnatal PM 10 exposure with OR (95% CI) of 1.18 (1.03–1.36), especially for CO and O 3 exposure during the first year with ORs (95% CI) = 1.08 (1.00–1.16) and 1.07 (1.00–1.14), as well as SO 2 exposure during the previous year with OR (95% CI) of 1.13 (1.02–1.25). The role of postnatal air pollution is more important for the risk of egg, milk and other food allergies. Renovation-related IAP (new furniture) and dampness-related indoor allergens exposures throughout all time windows significantly increased the risk of childhood DFA, with ORs ranging from 1.23 (1.03–1.46) to 1.54 (1.29–1.83). Furthermore, smoke-related IAP (environmental tobacco smoke [ETS], parental and grandparental smoking) exposure during pregnancy, first year, and previous year was related to DFA. Additionally, exposure to pet-related indoor allergens (cats) during first year and total plant-related allergens (particularly nonflowering plants) during previous year were associated with DFA. Moreover, exposure to plant-related allergy during first and previous year was specifically associated with milk allergy, while keeping cats during first year increased the risk of fruits/vegetables allergy. Life-time and early-life AU was associated with the increased risk of childhood DFA with ORs (95% CI) = 1.57 (1.32–1.87) and 1.46 (1.27–1.67), including different types food allergies except fruit/vegetable allergy. Postnatal OAP, life-time and early-life IEFs and AU exposure played a vital role in the development of DFA, supporting the "fetal origin of childhood FA" hypothesis. [Display omitted] • Postnatal exposure to outdoor CO, O 3 , SO 2 , and PM 10 was related with children's food allergy (FA). • Renovation- and smoke-related indoor air pollution (IAP) elevated the risk of childhood FA. • Dampness- and plant- related indoor allergens exposure increased risk of childhood FA. • Life-time and early-life antibiotic use increased the risk of childhood FA. • Children without using antibiotic had higher FA risk of outdoor and indoor environment exposure. [ABSTRACT FROM AUTHOR]

To investigate the role of different pattern of ambient air pollutants exposure during early life on childhood pneumonia, we conducted a retrospective cohort study of 3226 preschool children aged three to six years in Shenzhen, China during 2015 to 2016. Each child's exposure to three main air pollutants (PM10, SO2 and NO2) was calculated by the inverse distance weighted method. Multiple logistic regression analysis was used to investigate the pneumonia risk of early life exposure to air pollution. A relatively high prevalence of pneumonia (24.3%) among preschool children in Shenzhen was significantly associated with exposure to PM10 and SO2 during the first year of life, with adjusted odds ratios = 1.24 (1.05, 1.46) and 1.20 (1.05, 1.38) respectively. However, we observed no relationship between NO2 exposure and childhood pneumonia in pregnancy and first year of life. Sensitivity analysis suggested that boys, younger children (three to four years), non-preterm children, children without parental atopy and with exposure to environmental tobacco smoke were more susceptible to the impact of exposure to PM10 and SO2 on their suffering of pneumonia during their first year of life. Early-postnatal exposure to classical air pollution at low concentration during the first year of life can have an important role in enhancing the risk of childhood pneumonia, especially with the sensitive population. [ABSTRACT FROM AUTHOR]

Doctor-diagnosed plant allergy (DPA) in children has emerged as a significant global public health concern. However, the role of antibiotics and indoor environmental factors (IEFs) in childhood DPA remains unknown. To investigate the correlations between childhood DPA and exposure to antibiotics and IEFs during different time periods. A retrospective cohort study of 8,689 preschoolers was performed in Changsha, China. We collected data on each child's health outcomes, antibiotics use and home environment by a questionnaire, as well as temperature and air pollutants in Changsha, and calculated personal exposure to temperature and pollutants. Multiple logistic regression models were used to assess the independent and joint effects of antibiotics and IEFs on childhood DPA. Life-time and early-life antibiotics use was associated with childhood DPA with ORs (95% CI) = 1.58 (1.15–2.17) and 1.33 (1.04–1.69), with a higher risk for early-life exposure than later-life exposure. Renovation-specific indoor air pollution (IAP) during pre-birth (1 year before pregnancy and pregnancy) and smoke-specific IAP during early life (pregnancy and first year) had significantly impacts on childhood DPA. Furthermore, dampness-specific allergens throughout lifetime elevated the risk of DPA, with ORs ranging from 1.34 (1.00–1.81) to 1.93 (1.44–2.59). Moreover, life-time and early-life antibiotic use significantly increased the DPA risk attributed to some specific IEFs, such as ETS especially grandparental smoking, exposure during first year and previous year, with a significant interaction. Life-time and early-life exposure to antibiotics and IEFs independently and jointly played key roles in the development of DPA , supporting the "fetal origin of childhood PA" hypothesis. [Display omitted] • Life-time and early-life antibiotic use increased the risk of childhood plant allergy (PA). • Renovation-specific indoor air pollution (IAP) exposure before birth elevated the risk of PA. • Smoke-specific IAP exposure during early life was associated with increased risk of PA. • Dampness-specific indoor allergens exposure throughout lifetime was related with PA risk. • Antibiotic use significantly increased childhood PA risk attributed to smoke-specific IAP. [ABSTRACT FROM AUTHOR]

Building envelope dampness exposure is correlated with children's respiratory and allergic diseases. However, little research has compared the variation in the health impact of dampness exposure across multiple cities from a longitudinal perspective. A cross-sectional survey and a repeated one were conducted in children's residences in six cities: Chongqing, Shanghai, Nanjing, Wuhan, Changsha and Taiyuan, China, in 2010 (Phase I) and 2019 (Phase II). We selected 17,810 preschoolers during Phase I and 26,001 preschoolers during Phase II aged 3–6 years without changing residence since birth in the study. The proportion of residences with building envelope dampness exposure and the prevalence of respiratory and allergic diseases, except allergic rhinitis, in preschoolers significantly declined from Phase I to Phase II. Dampness exposure increased the risk for most childhood respiratory diseases in Phase II, with a 34% greater risk of lifetime-ever asthma in early residences and a 36% greater risk of current eczema in current residences. Most diseases showed a significantly positive exposure-response relationship to the cumulative period of building envelope dampness exposure (p < 0.05). The risk of developing current eczema was approximately 1.35 and 1.73 times higher in children exposed to both early and current dampness in Phase I and Phase II, respectively, than in children who had never been exposed. These findings provide new insights into the respiratory and allergic diseases in Chinese preschoolers because of building envelope dampness exposure over the last decade. The increased risk in Phase II raises concerns about the household's dampness environment. [Display omitted] • Building envelope dampness exposure has decreased over the last decade. • Prevalence of childhood respiratory diseases has declined over the last decade. • The risk of dampness exposure on respiratory diseases has increased in 2019. • Accumulated dampness exposure has a higher risk of current eczema in 2019. [ABSTRACT FROM AUTHOR]

Background Common cold is a frequent upper respiratory tract infection, but the role of ambient temperature in the infection is unclear. Objective We investigated the role of prenatal exposure to diurnal temperature variation (DTV), the difference between the daily maximal and minimal temperatures, in the risk of common cold in children. Methods We conducted a cohort study of 2598 preschool children in Changsha, China. Occurrence of common cold during the past year was surveyed using questionnaire. We then estimated each child's prenatal exposure to DTV during pregnancy. Multivariate logistic regression model was used to examine the association between occurrence of common cold and prenatal exposure to DTV in terms of odds ratios (OR) and 95% confidence interval (CI). Results About 45% children have common cold (≥3 times) during the past year. We found that common cold in children was associated with maternal DTV exposure during pregnancy, particularly during the first trimester with adjusted OR (95% CI) = 1.27 (1.10–1.46). Male and atopic children were more susceptible to the effect of DTV during pregnancy. The risk of common cold due to DTV is higher in children living in the suburban areas and the bigger houses and in those exposed to environmental tobacco smoke, mold/dampness, new furniture and redecoration. We observed that the risk of common cold in children has been increased in recent years due to increasing DTV. Conclusions Common cold in children was associated with maternal exposure to temperature variation during pregnancy, suggesting that the risk of common cold may originate in pregnancy. [ABSTRACT FROM AUTHOR]

The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM 2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM 2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1° × 0.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM 2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10 μg/m 3 of the annual PM 2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM 2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM 2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM 2.5 exposure. [ABSTRACT FROM AUTHOR]

Background There is some evidence that dampness, mould and cockroaches can increase the risk of respiratory infections in children but few studies exist from China on this topic. Aim To study associations between domestic early life exposure to biological indoor factors (dampness, mould, cats, dogs, rats, cockroaches), cleaning habits and common cold among pre-school children across China. Methods Children aged 3–6 years (n = 39,782) were recruited from randomly selected day care centres in seven cities in China. Data on common cold and prenatal and postnatal exposure to dampness, mould, windowpane condensation in wintertime (WPC), cats, dogs, cockroaches and rats were assessed by a parentally administered questionnaire. Data on annual ambient temperature and PM 10 was assessed on city level. Associations between high frequency (> 5 colds per year) and long duration (≥ 2 weeks) of common colds in the past year and exposure were calculated by multilevel logistic regression. Results A total of 9.2% had a high frequency and 11.9% had long duration of common cold. Exposure to mould (OR = 1.38, 95% CI 1.24–1.53) and WPC (OR 1.23, 95%CI 1.13–1.33) at birth was associated with frequent common cold. Exposure to dogs at birth was associated with long duration of common cold. (OR = 1.22, 95% CI 1.06–1.41). Exposure to mould (OR = 1.36, 95% CI 1.22–1.54), WPC (OR = 1.27, 95%CI 1.17–1.39) and water leakage (OR 1.34, 95% CI 1.20–1.49) in the current home was associated with frequent common cold. Presence of cockroaches were positively (OR = 1.12, 95% CI 1.02–1.24) and presence of rats (OR = 0.86, 95% CI 0.77–0.96) negatively associated with high frequency of common cold. Daily cleaning was negatively associated with frequent common cold (OR = 0.89, 95% CI 0.81–0.97). Similar associations for mould, WPC, cockroaches and rats were found for long duration. Ambient PM 10 (OR = 1.21, 95% CI 1.21–1.35 per 10 μg/m 3 ) and temperature (OR = 1.13, 95% CI 1.06–1.35 °C) on city level were associated with high frequency of common cold. Associations between cat keeping and high frequency of common cold were found only in southern China. Associations with cockroaches were stronger in northern China. Associations with dampness and mould were the same in the north and south. Conclusions Indoor mould, water damage, windowpane condensation, cockroaches and keeping cats or dogs as pets can be risk factors for common cold while daily cleaning can be protective factor. PM 10 and a warmer climate zone can be other risk factors for common cold. [ABSTRACT FROM AUTHOR]

Background Evidence linking prenatal exposure to outdoor air pollution with eczema in early childhood is scare, and the role of components of air pollution and exposure timing remains unclear. Objectives We investigated the association between exposure to air pollution during preconceptional and perinatal period and the risk of eczema in preschool children. Methods We conducted a prospective cohort study of 2598 children aged 3–6 years in Changsha, China. The prevalence of eczema was assessed by a standardized health questionnaire administered by the parents. Individual exposures to nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ) and particulate matter with an aerodynamic diameter ≤ 10 μm (PM 10 ) during the 4th-6th and 1st-3rd month before pregnancy, entire pregnancy, and three trimesters were estimated by an inverse distance weighted (IDW) method based on concentrations measured at monitoring stations. Association between childhood eczema and exposure to air pollution was examined by logistic regression models in terms of odds ratio (OR) and 95% confidence interval (CI) for an interquartile range (IQR) increase in exposure. Results Life-time prevalence of eczema in preschool children in Changsha was 28.6%. Childhood eczema was associated with traffic-related air pollutant NO 2 during 3 months before pregnancy and entire pregnancy with adjusted ORs = 1.19 (95% CI: 1.04–1.37) and 1.21 (95% CI: 1.03–1.42) respectively. The highest risk of eczema was observed for the 1st trimester exposure to NO 2 [OR = 1.26 (95% CI: 1.09–1.46)]. However, no association was detected for SO 2 and PM 10 exposure during any window. High-level exposure to NO 2 during the whole time period significantly increased the effect of NO 2 in all windows on eczema risk as compared with low-level exposure. Sensitivity analysis indicated that the association between both preconceptional and perinatal exposure to NO 2 and childhood eczema was consistent and robust, and this association was modified by some personal, parental hereditary and indoor environmental factors. Conclusion Our findings support the hypothesis that early childhood eczema is associated with exposure to traffic-related air pollutant during both preconceptional and perinatal period, especially at a high level of exposure. [ABSTRACT FROM AUTHOR]

Food allergy increased in the recent years causing heavy disease burden worldwide, yet the unique factors for the second-wave allergy epidemic since a rise of allergic diseases are unclear. To examine the impact of introduction timing of complementary foods on childhood food allergy and whether ambient air pollution modify this association. A retrospective cohort study of 2,598 preschoolers was conducted at 36 kindergartens at Changsha of China during 2011–2012. A standard questionnaire was developed to survey each preschooler's introduction timing of complementary foods, food allergy, and home environments. Each subject's exposure to ambient air pollutants including PM 10 , SO 2 , and NO 2 was estimated for pregnancy and postnatal period. Association between food allergy and introduction timing of complementary foods as well as its modification by ambient pollution were evaluated by multiple logistic regression model. Childhood total food allergy (14.6%) was significantly positively associated with early introduction to fruit or vegetable before 3 months with OR = 1.97 (1.25–3.11), especially for egg and milk allergies. Food allergy was also significantly associated with NO 2 exposure in pregnancy especially during the 1st trimester with ORs (95% CI) = 1.24 (1.00–1.54) and 1.27 (1.03–1.58) and postnatal period with OR of 1.30 (1.01–1.66) respectively for per IQR increase in their exposure. We observed that living near traffic-main road and other areas significantly increased food allergy risk of early introduction of fruit and vegetable. We further detected that early introduction of milk powder or porridge significantly decreased the risk of food allergy at the condition of light outdoor air pollution exposure during postnatal period. Sensitivity analysis showed that children living at urban area, male sex, younger age, and having breast-feeding were more susceptible to the effect of early introduction of fruit and vegetable on food allergy. Our study indicates that the role of introduction timing of complementary foods on food allergy could be adjusted by air pollution exposure level, which may partly explain the second-wave allergy epidemic and provide a potential preventive strategy. [Display omitted] • Childhood food allergy was associated with early introduction of fruit and vegetable before 3 months. • Food allergy was related to NO 2 exposure in pregnancy especially 1st trimester and postnatal stage. • Living near traffic area increased food allergy risk of early introduction of fruits and vegetables. • Low air pollution increased protective effect of early introduction of food allergens on food allergy. • Air pollution modified effect of solid food addition at different time on food allergy development. [ABSTRACT FROM AUTHOR]

Background Environmental factors have been found to be associated with allergic diseases, but it is unclear which environmental factor during which exposure window causes what kind of allergic diseases. Objectives We investigated association between exposure to some predominant outdoor and indoor environmental factors during preconceptional, prenatal, and postnatal periods and allergic diseases/symptoms in 2598 children in China. Methods Children's lifetime incidence of allergic diseases and current prevalence of allergic symptoms and exposure to indoor new furniture/redecoration and mold/dampness was surveyed by a questionnaire. Exposure to outdoor air pollutants was estimated by the concentrations measured at air quality monitoring stations. Multiple logistic regression model was used to evaluate the associations between outdoor air pollutants and indoor environmental factors and allergic diseases (asthma, allergic rhinitis, and eczema) and symptoms (wheezing, night cough, and rhinitis-like). Results We found that preconceptional, prenatal, and postnatal exposure to outdoor industrial and traffic air pollutants were significantly associated with increase in the risk of childhood asthma, and also positively associated with allergic rhinitis and eczema. However, we cannot distinguish the effect of outdoor air pollutants and exposure windows because of their high correlations. New furniture was associated with eczema and allergic rhinitis during postnatal exposure, but redecoration associated with asthma and eczema during prenatal exposure. Indoor visible mold/damp stains was significant for eczema during prenatal exposure and asthma during postnatal exposure respectively, but window condensation was significant for all childhood allergic diseases during both prenatal and postnatal exposures. Allergic symptoms in children were found to be associated with exposure to indoor factors only. Conclusions Associations between outdoor air pollutants and indoor environmental factors and childhood allergic diseases/symptoms were divergent and related to the timing of exposure. [ABSTRACT FROM AUTHOR]

There is growing evidence that allergic rhinitis (AR) is associated with indoor environmental factors, but their role in childhood AR during early life remains unclear. To investigate the association of preconceptional, prenatal, early postnatal, and current exposure to home environmental factors with childhood AR, and to further explore whether this association can be interacted by outdoor air pollution and temperature. A retrospective cohort study of 8689 preschool children was conducted during 2019–2020 in Changsha, China. A standard questionnaire was used to collect data on each family's health outcomes and home environments. We considered home environmental exposures during one year before conception, pregnancy, first year of life, and past year. Associations of indoor air pollution and allergens with AR were assessed by multiple logistic regression models. Pre-birth exposure to indoor air pollution emitted by new furniture or redecoration and dampness related allergen derived from mold/damp stains and mold/damp clothes or bedding during 1 year before conception and pregnancy was significantly associated with increased AR, with adjusted ORs (95% CI) ranging from 1.35 (1.05–1.75) to 1.87 (1.55–2.27). Childhood AR was also significantly related with post-birth exposure to dampness related indoor allergen including mold/damp stains and mold/damp clothes or bedding in first year and past year and pollen allergen including total and nonflowing plants in past year, with a range of ORs (95% CI) from 1.20 (1.01–1.42) to 1.79 (1.42–2.27). We identified that pre-birth, particularly in utero exposure to both indoor air pollution from renovation and dampness related allergens, played a key role in AR development compared to post-birth exposures, and accumulative effect was observed with the highest risk of AR. High exposure to traffic-related air pollution (TRAP) including outdoor PM 2.5 , NO 2 , CO, and O 3 , as well as living near traffic road not only significantly increased adverse effect of home environmental factors but also decreased protective effect of household dogs on childhood AR. Early life exposure to low temperature in pregnancy and high temperature in first year significantly increased AR risk of home environmental exposure. Sensitivity analysis indicated that some sub-groups were more susceptible to AR risk of home environmental exposure. Our study suggests that pre-birth exposure to home environmental factors played an important role in AR development and this effect can be interacted by TRAP and temperature, which supports a hypothesis of "(pre)fetal origin of childhood AR". [Display omitted] • Pre-birth home air pollution and allergen were related with allergic rhinitis (AR). • Post-birth home mold/dampness and plant allergens exposure increased AR risk. • Pre-birth is a critical window for AR risk of home environmental exposure. • Traffic-related air pollution increased AR risk of indoor environmental exposure. • Low and high temperature interacted with indoor environment on AR in early life. [ABSTRACT FROM AUTHOR]

Prevalence of allergic rhinitis has rapidly increased among Chinese children, but the reasons are unclear. Recent findings have suggested that exposure to outdoor air pollutants may increase the risk of allergic rhinitis, but the results were inconsistent. This study further investigated the effect of outdoor air pollutants on allergic rhinitis among preschool children. A standardized questionnaire on health, home and environmental factors was conducted for 4988 children aged 1–8 in the city of Changsha, and the concentrations of PM 10 (particle diameter ⩽10 μm), sulfur dioxide (SO 2) and nitrogen dioxide (NO 2) during 2006–2011 were acquired from the official web of Changsha Environmental Protection Agency. Results showed that the prevalence of children’s doctor diagnosed rhinitis was 8.4% (95% confidence interval [CI] 7.0%–10.0%). It was found that the prevalence of rhinitis was not associated with site-specific background concentrations of air pollutants, but significantly positively correlated with age-related accumulative personal exposure of PM 10, SO 2 and NO 2. We conclude that age-related accumulative personal exposure to ambient air pollution may play an important role in the development of rhinitis. [ABSTRACT FROM AUTHOR]

Few studies focus on the associations of green space composition and configuration with children's allergic rhinitis (AR). A multi-center population-based cross-sectional study was performed in 7 cities in mainland of China between 2019 and 2020, recruiting 36,867 preschool children. Information on the current AR symptoms and demographics were collected by questionnaire. Exposure to residential greenness was estimated by Normalized Difference Vegetation Index (NDVI, 1000 m buffer) around the residences. Greenness composition was estimated in 3 main categories: forest, grassland, shrubland. Configuration of each category and total greenness (a spatial resolution of 10 m × 10 m) was estimated by 6 landscape pattern metrics to quantify their area, shape complexity, aggregation, connectivity, and patch density. Exposure to daily ambient particulate matter (PM 1 , PM 2.5 and PM 10 , a spatial resolution of 1 km × 1 km) was estimated. Multilevel logistic regression models were applied to analyze the associations of greenness and its composition and configuration with AR, and mediation effects by PMs were examined by mediation analysis models. The prevalence of self-reported current AR in preschool children was 33.1%. Two indicators of forest, Aggregation Index of forest patches (AIforest) (odds ratio (OR):0.92, 95% Confidential Interval (CI): 0.88–0.97), and Patch Cohesion of forest (COHESIONforest) (OR: 0.93, 95% CI:0.89–0.98) showed significantly negative associations with AR symptoms. Mediation analyses found the associations were partially mediated by PMs. Age, exclusive breastfeed duration and season were the potential effect modifiers. The associations varied across seven cities. Our findings suggest the inverse associations of the aggregation and connectivity of forest patches surrounding residence addresses with AR symptoms. Since the cross-sectional study only provides associations rather than causation, further studies are needed to confirm our results as well as the underlying mechanisms. • Forest aggregation and connectivity were negatively associated with AR symptoms. • Particulate matters mediated the inverse association of forest configuration with AR. • Age, exclusive breastfeed duration and season were the effect modifiers. [ABSTRACT FROM AUTHOR]

[Display omitted] Emerging evidence suggests that early-life (in-utero and first-year since birth) exposure to ambient PM 2.5 is a risk factor for asthma onset and exacerbation among children, while the hazards caused by PM 2.5 compositions remain largely unknown. To examine potential associations of early-life exposures to PM 2.5 mass and its major chemical constituents with childhood asthma and wheezing. By conducting the Phase II of the China, Children, Homes, Health study, we investigated 30,325 preschool children aged 3–6 years during 2019–2020 in mainland China. Early-life exposure to PM 2.5 mass and its constituents (i.e., black carbon [BC], organic matter [OM], nitrate, ammonium, sulfate) were calculated based on monthly estimates at a 1 km × 1 km resolution from satellite-based models. We adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM 2.5 constituents on childhood asthma/wheezing. The average PM 2.5 concentrations during in-utero and the first year since birth were 64.7 ± 10.6 and 61.8 ± 10.5 µg/m3, respectively. Early-life exposures to a mixture of major PM 2.5 constituents were significantly associated with increased risks of asthma and wheezing, while no evident compositions-wheezing associations were found in the first year. Each quintile increases in all five PM 2.5 components exposures in utero was accordingly associated with an odds ratio of 1.18 [95% confidence interval: 1.07–1.29] for asthma and 1.08 [1.01–1.16] for wheezing. BC, OM and SO 4 2− contributed more to risks of asthma and wheezing than the other PM 2.5 constituents during early life, wherein the effects of BC were only observed during pregnancy. Sex subgroup analyses suggested stronger associations among girls of first-year exposures to PM 2.5 components with childhood asthma. Early-life exposures to ambient PM 2.5 , particularly compositions of BC, OM and SO 4 2−, are associated with an increased risk of childhood asthma. [ABSTRACT FROM AUTHOR]

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. • Dampness/mold can be risk factors for adult asthma, allergic rhinitis or eczema. • Living in old buildings can be a risk factor for adult asthma and allergic rhinitis. • Less urbanized areas have less adult asthma, allergic rhinitis and eczema. • High ambient temperature and high precipitation can influence eczema. [ABSTRACT FROM AUTHOR]