Traffic density and stationary sources of air pollution associated with wheeze, asthma, and immunoglobulin E from birth to age 5 years among New York City children

Prenatal exposure to air pollutant mixtures and birthweight in the upstate KIDS cohort

BACKGROUND

Single-pollutant models have linked prenatal PM2.5 exposure to lower birthweight. However, analyzing air pollutant mixtures better captures pollutant interactions and total effects. Unfortunately, strong correlations between pollutants restrict traditional methods.

OBJECTIVES

We explored the association between exposure to a mixture of air pollutants during different gestational age windows of pregnancy and birthweight.

METHODS

We included 4,635 mother-infant dyads from a New York State birth cohort born 2008-2010. Air pollution data were sourced from the EPA's Community Multiscale Air Quality model and matched to the census tract centroid of each maternal home address. Birthweight and gestational age were extracted from vital records. We applied linear regression to study the association between prenatal exposure to PM2.5, PM10, NOX, SO2, and CO and birthweight during six sensitive windows. We then utilized Bayesian kernel machine regression to examine the non-linear effects and interactions within this five-pollutant mixture. Final models adjusted for maternal socio-demographics, infant characteristics, and seasonality.

RESULTS

Single-pollutant linear regression models indicated that most pollutants were associated with a decrement in birthweight, specifically during the two-week window before birth. An interquartile range increase in PM2.5 exposure (IQR: 3.3 µg/m3) from the median during this window correlated with a 34 g decrement in birthweight (95 % CI: -54, -14), followed by SO2 (IQR: 2.0 ppb; β: -31), PM10 (IQR: 4.6 µg/m3; β: -29), CO (IQR: 60.8 ppb; β: -27), and NOX (IQR: 7.9 ppb; β: -26). Multi-pollutant BKMR models revealed that PM2.5, NOX, and CO exposure were negatively and non-linearly linked with birthweight. As the five-pollutant mixture increased, birthweight decreased until the median level of exposure.

DISCUSSION

Prenatal exposure to air pollutants, notably PM2.5, during the final two weeks of pregnancy may negatively impact birthweight. The non-linear relationships between air pollution and birthweight highlight the importance of studying pollutant mixtures and their interactions.

Different Impacts of Traffic-Related Air Pollution on Early-Onset and Late-Onset Asthma

Background

Early-onset asthma (EOA) and late-onset asthma (LOA) are two distinct phenotypes. Air pollution has been associated with an increase in poorer asthma outcomes. The objective of this study was to examine the effects of traffic-related air pollution (TRAP) on asthma outcomes in EOA and LOA patients.

Methods

A cross-sectional study was conducted on 675 asthma patients (LOA: 415) recruited from a major medical center in Taiwan. The land-use regression (LUR) model was used to estimate the level of exposure to PM10, PM2.5, NO2, and O3 on an individual level. We investigated the association between TRAP and asthma outcomes in EOA and LOA patients, stratified by allergic sensitization status, using a regression approach.

Results

An increase in PM10 was associated with younger age of onset, increased asthma duration, and decreased lung function in EOA patients (p<0.05). An increase in PM10 was associated with older age of onset, and decreased asthma duration, eosinophil count, and Asthma Control Test (ACT) score in LOA patients. An increase in PM2.5 was associated with younger age of onset, increased asthma duration, decreased eosinophil count, and lung function in EOA patients (p<0.05). An increase in PM2.5 was associated with decreased lung function and ACT score in LOA patients. An increase in NO2 was associated with increased eosinophil count and decreased lung function in EOA patients (p<0.05). An increase in O3 was associated with decreased lung function in LOA patients (p<0.05). In addition, associations of TRAP with age of onset and eosinophil counts were mainly observed in both EOA and LOA patients with allergic sensitization, and an association with ACT was mainly observed in LOA patients without allergic sensitization.

Conclusion

The impact of TRAP on age of onset, eosinophil count, and lung function in EOA patients, and ACT in LOA patients, was affected by the status of allergic sensitization.

Environmental inequality: Air pollution and asthma in children

INTRODUCTION

Whether you benefit from high-quality urban environments, such as those rich in green and blue spaces, that may offer benefits to allergic and respiratory health depends on where you live and work. Environmental inequality, therefore, results from the unequal distribution of the risks and benefits that stem from interactions with our environment.

METHODS

Within this perspective, this article reviews the evidence for an association between air pollution caused by industrial activities, traffic, disinfection-by-products, and tobacco/e-cigarettes, and asthma in children. We also discuss the proposed mechanisms by which air pollution increases asthma risk, including environmental epigenetic regulations, oxidative stress, and damage, disrupted barrier integrity, inflammatory pathways, and enhancement of respiratory sensitization to aeroallergens.

RESULTS AND CONCLUSIONS

Environmental air pollution is a major determinant of childhood asthma, but the magnitude of effect is not shared equally across the population, regions, and settings where people live, work, and spend their time. Improvement of the exposure assessment, a better understanding of critical exposure time windows, underlying mechanisms, and drivers of heterogeneity may improve the risk estimates. Urban conditions and air quality are not only important features for national and local authorities to shape healthy cities and protect their citizens from environmental and health risks, but they also provide opportunities to mitigate inequalities in the most deprived areas where the environmental burden is highest. Actions to avoid exposure to indoor and outdoor air pollutants should be complementary at different levels-individual, local, and national levels-to take effective measures to protect children who have little or no control over the air they breathe.

The influence of urban exposures and residence on childhood asthma

Children with asthma who live in urban neighborhoods experience a disproportionately high asthma burden, with increased incident asthma and increased asthma symptoms, exacerbations, and acute visits and hospitalizations for asthma. There are multiple urban exposures that contribute to pediatric asthma morbidity, including exposure to pest allergens, mold, endotoxin, and indoor and outdoor air pollution. Children living in urban neighborhoods also experience inequities in social determinants of health, such as increased poverty, substandard housing quality, increased rates of obesity, and increased chronic stress. These disparities then in turn can increase the risk of urban exposures and compound asthma morbidity as poor housing repair is a risk factor for pest infestation and mold exposure and poverty is a risk factor for exposure to air pollution. Environmental interventions to reduce in-home allergen concentrations have yielded inconsistent results. Population-level interventions including smoking bans in public places and legislation to decrease traffic-related air pollution have been successful at reducing asthma morbidity and improving lung function growth. Given the interface and synergy between urban exposures and social determinants of health, it is likely population and community-level changes will be needed to decrease the excess asthma burden in children living in urban neighborhoods.

Gestational exposure to titanium dioxide, diesel exhaust, and concentrated urban air particles affects levels of specialized pro-resolving mediators in response to allergen in asthma-susceptible neonate lungs

Maternal gestational exposures to traffic and urban air pollutant particulates have been linked to increased risk and/or worsening asthma in children; however, mechanisms underlying this vertical transmission are not entirely understood. It was postulated that gestational particle exposure might affect the ability to elicit specialized proresolving mediator (SPM) responses upon allergen encounter in neonates. Lipidomic profiling of 50 SPMs was performed in lungs of neonates born to mice exposed to concentrated urban air particles (CAP), diesel exhaust particles (DEP), or less immunotoxic titanium dioxide particles (TiO2). While asthma-like phenotypes were induced with identical eosinophilia intensity across neonates of all particle-exposed mothers, levels of LXA4, HEPE and HETE isoforms, and HDoHe were only decreased by CAP and DEP only but not by TiO2. However, RvE2 and RvD1 were inhibited by all particles. In contrast, isomers of Maresin1 and Protectin D1 were variably elevated by CAP and DEP, whereas Protectin DX, PGE2, and TxB2 were increased in all groups. Only Protectin D1/DX, MaR1(n-3,DPA), 5(S),15(S)-DiHETE, PGE2, and RvE3 correlated with eosinophilia but the majority of other analytes, elevated or inhibited, showed no marked correlation with inflammation intensity. Evidence indicates that gestational particle exposure leads to both particle-specific and nonspecific effects on the SPM network.

Asthma and the social determinants of health

OBJECTIVE

To synthesize the growing body of literature on the role of social determinants of health (SDoH) in asthma and asthma disparities.

DATA SOURCES

A pubmed.gov search was performed to identify published literature on SDoH, asthma, asthma disparities, and race and ethnicity. Current asthma statistics of the Centers for Disease Control and Prevention were reviewed.

STUDY SELECTIONS

Relevant articles on SDoH, asthma, asthma disparities, and race and ethnicity were reviewed in detail.

RESULTS

Black and Latinx Americans have a higher asthma prevalence and greater asthma morbidity than White Americans and also bear a disproportionate burden of SDoH. Inequities in SDoH are rooted in structural racism and population-level injustices that affect the socioeconomic status, physical environment, and health care access/quality of Black and Latinx Americans. There is evidence that racial/ethnic inequities in SDoH, such as socioeconomic status, neighborhood environment, housing, environmental exposures, and health care access/quality, contribute to excess burden of asthma prevalence/incidence, morbidity, exacerbations, and abnormal lung function among certain racial/ethnic populations. In addition, Black and Latinx communities experience high levels of long-term stress, which may increase asthma risk through direct effects on the immune system and hypothalamic-pituitary-adrenocortical activation. Long-term stress may also mediate the effects of SDoH on asthma.

CONCLUSION

Although there is clear evidence linking SDoH to excess asthma risk and implicating SDoH in asthma disparities, the extent to which asthma disparities are explained by inequities in SDoH and the relative contributions of each of these SDoH to asthma disparities remain unclear. This knowledge is needed to effectively develop and test systems-level interventions targeting SDoH, with the ultimate goal of meaningfully reducing racial/ethnic asthma disparities.

Systematic review of preclinical studies on the neutrophil-mediated immune response to air pollutants, 1980-2020

Preclinical evidence about the neutrophil-mediated response in exposure to air pollutants is scattered and heterogeneous. This has prevented the consolidation of this research field around relevant models that could advance towards clinical research. The purpose of this study was to systematic review the studies of the neutrophils response to air pollutants, following the recommendations of the Cochrane Collaboration and the PRISMA guide, through 54 search strategies in nine databases. We include 234 studies (in vitro, and in vivo), being more frequent using primary neutrophils, Balb/C and C57BL6/J mice, and Sprague-Dawley and Wistar rats. The most frequent readouts were cell counts, cytokines and histopathology. The temporal analysis showed that in the last decade, the use of mice with histopathological and cytokine measurement have predominated. This systematic review has shown that study of the neutrophils response to air pollutants started 40 years ago, and composed of 100 different preclinical models, 10 pollutants, and 11 immunological outcomes. Mechanisms of neutrophils-mediated immunopathology include cellular activation, ROS production, and proinflammatory effects, leading to cell-death, oxidative stress, and inflammatory infiltrates in lungs. This research will allow consolidating the research efforts in this field, optimizing the study of causal processes, and facilitating the advance to clinical studies.

Proximity to Heavy Traffic Roads and Patient Characteristics of Late of Onset Asthma in an Urban Asthma Center

Background: Traffic-related pollution is associated with the onset of asthma and the development of different phenotypes of asthma. Few studies have investigated the association between traffic proximity and late-onset of asthma (LOA) and early-onset asthma (EOA). This study was conducted to investigate the associations of LOA phenotypes with a function of the distance between residence and heavy traffic roads (HTRs).

Methods: The study group consisted of 280 patients who were (LOA: 78.4%) recruited consecutively from a pay-for-performance asthma program to clarify the patient characteristics and proximity to HTRs within 1,000 m from their residences between EOA and LOA in three urban centers in Taiwan. The subsequent analysis focused on patients with LOA (n = 210) linking phenotypes and distance to HTRs.

Results: Subjects with LOA tended to be older than those with EOA and had shorter asthma duration, poorer lung function, lower atopy, and less exposure to fumes or dust at home. Patients with LOA were more likely than those with EOA to live within 900 m of two or more HTRs (14.3 vs. 3.4%, p = 0.02). Among patients with LOA, minimum distance to an HTR was negatively associated with numbers of specific IgE as well as positively associated with the age of onset and body weight significantly. A higher proportion of patients with atopy (26.3 vs. 20.6%, p = 0.001. odds ratio [OR]: 2.82) and anxiety/depression (21.0 vs. 18.1%, p = 0.047. OR: 1.81) and a trend of lower proportion of patients with obese (5.7 vs. 12.4%, p = 0.075) were found to be living within 900 m from HTRs.

Conclusions: Late-onset of asthma (LOA) tended to live in areas of higher HTR density compared to EOAs. Among patients with LOA living close to HTRs, the interaction between traffic-related pollution, allergy sensitization, and mood status were the factors associated with asthma onset early. Obesity may be the factor for later onset who live far from HTRs.

Allergic and non-allergic asthma phenotypes and exposure to air pollution

OBJECTIVE

Although harmful effects of air pollution on airway diseases are well-established, its effect on allergy still remains unclear. The aim of this study was to examine changes on asthma clinic and oxidant homeostasis due to air pollution between allergic asthma (AA) and non-allergic asthma (NA) phenotypes.

METHODS

This prospective, case-control study included patients with well-controlled asthma under regular treatment (n = 57) and healthy individuals (n = 51). Of asthma patients, 22 had AA and 35 had NA phenotypes. Respiratory symptoms, pulmonary function tests, serum total antioxidant status (TAS) and total oxidant status (TOS), and thiol/disulfide levels were compared between the most (V₁) and least (V₂) air-polluted times.

RESULTS

High air pollution exposure resulted to an increase in the frequency of respiratory symptoms and serum inflammation markers in both asthmatic and healthy individuals. Frequency of dyspnea and cough in AA and rhinitis in NA decreased from V₁ to V₂. Hospitalization due to asthma exacerbation, systemic corticosteroid use, and eosinophil counts were more frequent in NA group than AA in V1. An increase of blood eosinophil counts was observed in AA group at the same visit. Mean TAS and TOS levels were higher in asthma group than control group, and the decline in TAS and TOS levels from V₁ to V₂ was seen only in NA. All thiols decreased and SH/total SH ratios significantly increased from V₁ to V₂ in all groups.

CONCLUSION

This study demonstrates that air pollution affects both asthma patients and healthy individuals. Through oxidant-antioxidant and thiol pathways, however, it adversely affects respiratory system of asthma patients, at a greater extent, than healthy individuals.

Role of diesel exhaust particles in the induction of allergic asthma to low doses of soybean

INTRODUCTION

Exposure to environmental pollutants such as diesel exhaust particles (DEP) increases the risk of asthma and asthma exacerbation. However, the exact mechanisms inducing asthma to low doses of allergens remain poorly understood. The present study aimed to analyse the immunomodulatory effect of the inhalation of DEP in a mouse model exposed to non-asthmagenic doses of soybean hull extract (SHE).

MATERIAL AND METHODS

BALB/c ByJ mice were randomly divided into four experimental groups. Two groups received nasal instillations of saline and the other two groups received 3 mg ml-1 SHE during 5 days per week for 3 weeks. One group in each pair also received 150 μg of DEP in the same instillations 3 days per week. SHE-specific IgE levels, oxidative stress, leukocyte pattern and optical projection tomography (OPT) imaging studies were assessed.

RESULTS

Inhalation of SHE and/or DEP increased levels of H2O2 in BAL, while coexposure to SHE and DEP increased SHE-specific IgE levels in serum. Inhalation of SHE alone increased eosinophils, B cells, total and resident monocytes and decreased levels of NK cells, while inhalation of DEP increased neutrophils and decreased total monocytes. Regarding dendritic cells (DC), the inhalation of SHE and/or DEP increased the total population, while the inhalation of SHE alone increased Th2-related DCs (CD11b + Ly6C-) and decreased tolerogenic DCs (CD11b-Ly6C-). However, coexposure to SHE and DEP increased oxidative stress-sensitive DCs (CD11b-Ly6C+) and decreased Th1-related DCs (CD11b + Ly6C+). As regards macrophages, inhalation of SHE and DEP decreased total and alveolar populations. DEP deposition in lung tissue did not differ between groups.

CONCLUSION

Coexposure to DEP activates the asthmatic response to low doses of soy by triggering the immune response and oxidative stress.

Proximity to Major Roads and Risks of Childhood Recurrent Wheeze and Asthma in a Severe Bronchiolitis Cohort

Air pollution exposures have been suggested as risk factors for childhood respiratory diseases. We investigated proximity to major roads, an indicator of air pollution exposure, and its associations with childhood recurrent wheeze and asthma. We used data from a multicenter prospective cohort study of 921 infants hospitalized for bronchiolitis and recruited from 14 U.S. states. Primary exposure was residential proximity to the nearest major road at birth through age 3 years. Residential distance from nearest major road was divided into four categories: <100, 100–200, 201–300, and >300 m. Outcomes were parent-reported recurrent wheeze by age 3 years and asthma by age 5 years. Associations between residential proximity to major roads and respiratory outcomes were investigated using multivariable Cox proportional hazards modeling and logistic regression, adjusted for confounders. Out of 920 participants with home address data, pooled estimates identified 241 (26%) participants resided within 300 m of a major road, 296 (32%) developed recurrent wheeze by age 3, and 235 out of 858 participants (27%) developed asthma by 5 years. Participants who resided close to a major road had the highest risk of recurrent wheeze (adjusted hazards ratio for <100 m, 1.59, 95%CI: 1.08–2.33) and asthma (adjusted odds ratio for 201–300 m, 1.62, 95%CI: 1.16–2.25), compared to those residing >300 m from a major road. Proximity to major roads is associated with increased risks of recurrent wheeze and asthma in young children.

A national cross-sectional study of exposure to outdoor nitrogen dioxide and aeroallergen sensitization in Australian children aged 7-11 years

The prevalence of allergic diseases in Australian children is high, but few studies have assessed the potential role of outdoor air pollution in allergic sensitization. We investigated the association between outdoor air pollution and the prevalence of aeroallergen sensitization in a national cross-sectional study of Australian children aged 7-11 years. Children were recruited from 55 participating schools in 12 Australian cities during 2007-2008. Parents completed a detailed (70-item) questionnaire. Outdoor nitrogen dioxide (NO₂), as a proxy for exposure to traffic-related emissions, was estimated using measurements from regulatory monitors near each school and a national land-use regression (LUR) model. Three averaging periods were assessed, using information on duration of residence at the address, including lifetime, previous (lifetime, excluding the last year), and recent (the last year only). The LUR model was used as an additional source of recent exposure estimates at school and home addresses. Skin prick tests (SPTs) were performed to measure sensitization to eight common aeroallergens. Multilevel logistic regression estimated the association between NO₂ and sensitization (by individual allergens, indoor and outdoor allergens, and all allergens combined), after adjustment for individual- and area-level covariates. In total, 2226 children had a completed questionnaire and SPT. The prevalence of sensitization to any allergen was 44.4%. Sensitization to house dust mites (HDMs) was the most common (36.1%), while sensitization to Aspergillus was the least common (3.4%). Measured mean (±s.d.) NO₂ exposure was between 9 (±2.9) ppb and 9.5 (±3.2) ppb, depending on the averaging period. An IQR (4 ppb) increase in measured previous NO₂ exposure was associated with greater odds of sensitization to HDMs (OR: 1.21, 95% CI: 1.01-1.43, P = 0.035). We found evidence of an association between relatively low outdoor NO₂ concentrations and sensitization to HDMs, but not other aeroallergens, in Australian children aged 7-11 years.

Multiple environmental exposures in early-life and allergy-related outcomes in childhood

INTRODUCTION

Early onset and high prevalence of allergic diseases result in high individual and socio-economic burdens. Several studies provide evidence for possible effects of environmental factors on allergic diseases, but these are mainly single-exposure studies. The exposome provides a novel holistic approach by simultaneously studying a large set of exposures. The aim of the study was to evaluate the association between a broad range of prenatal and childhood environmental exposures and allergy-related outcomes in children.

MATERIAL AND METHODS

Analyses of associations between 90 prenatal and 107 childhood exposures and allergy-related outcomes (last 12 months: rhinitis and itchy rash; ever: doctor-diagnosed eczema and food allergy) in 6-11 years old children (n = 1270) from the European Human Early-Life Exposome cohort were performed. Initially, we used an exposome-wide association study (ExWAS) considering the exposures independently, followed by a deletion-substitution-addition selection (DSA) algorithm considering all exposures simultaneously. All the exposure variables selected in the DSA were included in a final multi-exposure model using binomial general linear model (GLM).

RESULTS

In ExWAS, no exposures were associated with the outcomes after correction for multiple comparison. In multi-exposure models for prenatal exposures, lower distance of residence to nearest road and higher di-iso-nonyl phthalate level were associated with increased risk of rhinitis, and particulate matter absorbance (PM_abs) was associated with a decreased risk. Furthermore, traffic density on nearest road was associated with increased risk of itchy rash and diethyl phthalate with a reduced risk. DSA selected no associations of childhood exposures, or between prenatal exposures and eczema or food allergy.

DISCUSSION

This first comprehensive and systematic analysis of many environmental exposures suggests that prenatal exposure to traffic-related variables, PM_abs and phthalates are associated with rhinitis and itchy rash.

Air Pollution and Asthma: Mechanisms of Harm and Considerations for Clinical Interventions

There is global concern regarding the harmful impact of polluted air on the respiratory health of patients with asthma. Multiple epidemiologic studies have shown ongoing associations between high levels of air pollution and poor early life lung growth, development of allergic sensitization, development of asthma, airway inflammation, acutely impaired lung function, respiratory tract infections, and asthma exacerbations. However, studies have often yielded inconsistent findings, and not all studies have found significant associations; this may be related to both variations in statistical, measurement, and modeling methodologies between studies as well as differences in the concentrations and composition of air pollution globally. Overall, this variation in findings suggests we still do not fully understand the effects of ambient pollution on the lungs and on the evolution and exacerbation of airway diseases. There is clearly a need to augment epidemiologic studies with experimental studies to clarify the underlying mechanistic basis for the adverse responses reported and to identify the key gaseous and particle-related components within the complex air pollution mixture driving these outcomes. Some progress toward these aims has been made. This article reviews studies providing an improved understanding of causal pathways linking air pollution to asthma development and exacerbation. The article also considers potential strategies to reduce asthma morbidity and mortality through regulation and behavioral/pharmacologic interventions, including a consideration of pollutant avoidance strategies and antioxidant and/or vitamin D supplementation.

Parental PM2.5 Exposure-Promoted Development of Metabolic Syndrome in Offspring Is Associated With the Changes of Immune Microenvironment

Parental exposure to ambient fine particulate matter (PM2.5) has been associated with some of adverse health outcomes in offspring. The association between parental PM2.5 exposure and the development of metabolic syndrome (MetS) in offspring, and the effects of parental PM2.5 exposure on the susceptibility of offspring mice to PM2.5, has not been evaluated. The C57BL/6 parental mice (male and female mice) were exposed to filtered air (FA) or concentrated PM2.5 (PM) using Shanghai-METAS for a total of 16 weeks. At week 12 during the exposure, we allowed the parental male and female mice to breed offspring mice. The male offspring mice were divided into 4 groups and exposed to PM and FA again. The results showed that whether the parental mice were exposed to PM2.5 or not, the offspring mice exposure to PM2.5 appeared the elevation of blood pressure, insulin resistance, impairment of glucose tolerance, and dyslipidemia when compared to the offspring mice exposure to FA. More importantly, no matter what the offspring mice were exposed to, parental PM exposure overwhelmingly impacted the fasting blood insulin, homeostasis model assessment-insulin resistance, serous low-density lipoprotein cholesterol, and total cholesterol, splenic T helper cell 17 (Th17) and Treg cells, serous interleukin (IL)-17A, IL-6, and IL-10 in offspring mice. The results suggested that the parental exposure to air pollution might induce the development of MetS in offspring and might enhance the susceptibility of offspring to environmental hazards. The effects of parental PM exposure on offspring might be related to the changes of immune microenvironment.

The immunomodulatory effects of diesel exhaust particles in asthma

Ammonium persulfate (AP) causes occupational asthma (OA) and diesel exhaust particles (DEP) exacerbate asthma; however, the role of DEP in asthma due to chemical agents has not been assessed to date. Therefore, the present work aims to study the immunomodulatory effects of DEP in a mouse model of chemical asthma. BALB/c ByJ mice were randomly divided into four experimental groups. On days 1 and 8, mice were dermally sensitized with AP or saline. On days 15, 18 and 21, they received intranasal instillations of AP or saline. Two experimental groups received DEP on every of the three challenges. Airway hyperresponsiveness (AHR), lung mechanics, pulmonary inflammation in bronchoalveolar lavage, leukocyte numbers in total lung tissue, oxidative stress and optical projection tomography (OPT) studies were assessed. The AP-sensitized and challenged group showed asthma-like responses, such as airway hyperresponsiveness, increased levels of eosinophils and NKs and lower numbers of monocytes and CD11b-Ly6C- dendritic cells (DCs). Mice exposed to DEP alone showed increased levels of neutrophils and NKs, reduced numbers of monocytes and alveolar macrophages, and increased levels of CD11b + Ly6C- DCs. The AP sensitized and AP + DEP challenged group also showed asthma-like symptoms such as AHR, as well as increased numbers of eosinophils, neutrophils, CD11b + Ly6C- DCs and decreased levels of total and alveolar macrophages and tolerogenic DCs. Particle deposition was visualised using OPT. In the DEP group the particles were distributed relatively evenly, while in the AP + DEP group they were seen mainly in the large conducting airways. The results show that DEP exposure activates the innate immune response and, together with AP, exacerbates asthma immune hallmarks. This mouse model provides the first evidence of the capacity of DEPs to increase CD11b + Ly6C- (Th2-related) DCs. This study also demonstrates, for the first time, a differential deposition pattern of DEP in lungs depending on asthma status.

Ancestry-based intracategorical injustices in carcinogenic air pollution exposures in the United States

Previous studies of US environmental inequalities have focused on racial/ethnic differences in air pollutant exposure. Few have applied an intracategorical framework, which enables the identification of within-group differences through the examination of subgroups. We applied this framework to examine exposure disparities between 26 ancestry/ethnic origin groups within five US racial/ethnic categories. Data come from the US Census, American Community Survey, and National Air Toxics Assessment. We calculated national population-weighted lifetime cancer risk (LCR) scores from residential exposure to hazardous air pollutants. Results showed that Americans of Dominican, Ethiopian, and Somalian descent have the highest total LCR scores at 53.1, 49.2, and 48.3 estimated excess cases of cancer per one million people, respectively. Use of the intracategorical framework enabled characterization of disparate risks that would be overlooked based on the conventional assumption that racial/ethnic environmental inequalities conform to broad, homogenous categories. Intracategorical studies can inform interventions by identifying environmentally-disadvantaged socio-demographic groups.

Association between exposure to traffic-related air pollution and pediatric allergic diseases based on modeled air pollution concentrations and traffic measures in Seoul, Korea: a comparative analysis

BACKGROUND

Pediatric allergic diseases are a major public health concern, and previous studies have suggested that exposure to traffic-related air pollution (TRAP) exposure is a risk factor. These studies have typically assessed TRAP exposure using traffic measures, such as distance to major roads, or by modeling air pollutant concentrations; however inconsistent associations with pediatric allergic diseases have often been found. Using road proximity and density, we previously found an association between TRAP and atopic eczema among approximately 15,000 children living in Seoul, Korea, heavily populated and highly polluted city in which traffic is a major emission source. We aimed to conduct a parallel analysis using modeled air pollution concentrations and thus examine the consistency of the association. Specifically, we examined the associations of individual-level annual-average concentrations of NO₂, PM₁₀, and PM_2.5 with symptoms and diagnoses of three pediatric allergic diseases including asthma, allergic rhinitis, and atopic eczema.

METHODS

The study population included 14,614 children from the Seoul Atopy Friendly School Project Survey in Seoul, Korea, in 2010. To assess individual exposures to TRAP among these children, we predicted annual-average concentrations of NO₂, PM₁₀, and PM_2.5 at the children's home addresses in 2010 using universal kriging and land use regression models along with regulatory air quality monitoring data and geographic characteristics. Then, we estimated odds ratios (ORs) of the three allergic diseases for interquartile increases in air pollution concentrations after adjusting for individual risk factors in mixed effects logistic regression.

RESULTS

Symptoms and diagnoses of atopic eczema symptoms showed an association with NO₂ (OR = 1.07, 95% confidence interval = 1.02-1.13; 1.08, 1.03-1.14) and PM₁₀ (1.06, 1.01-1.12; 1.07, 1.01-1.13). ORs of PM_2.5 were positive but not statistically significant (1.01, 0.95-1.07; 1.04, 0.98-1.10). No association was found between asthma and allergic rhinitis, although PM_2.5 showed a marginal association with allergic rhinitis.

CONCLUSIONS

Our consistent findings regarding the association between TRAP and the prevalence of atopic eczema using traffic measures and surrogate air pollutants suggested the effect of TRAP on children's health. Follow-up studies should elucidate the causal link, to support subsequent policy considerations and minimize adverse health effects in children.

Home environmental and lifestyle factors associated with asthma, rhinitis and wheeze in children in Beijing, China

BACKGROUND

The prevalence of asthma and allergic diseases has increased rapidly in urban China since 2000. There has been limited study of associations between home environmental and lifestyle factors with asthma and symptoms of allergic disease in China.

METHODS

In a cross-sectional analysis of 2214 children in Beijing, we applied a two-step hybrid Least Absolute Shrinkage and Selection Operator (LASSO) algorithm to identify environmental and lifestyle-related factors associated with asthma, rhinitis and wheeze from a wide range of candidates. We used group LASSO to select variables, using cross-validation as the criterion. Effect estimates were then calculated using adaptive LASSO. Model performance was assessed using Area Under the Curve (AUC) values.

RESULTS

We found a number of environmental and lifestyle-related factors significantly associated with asthma, rhinitis or wheeze, which changed the probability of asthma, rhinitis or wheeze from -5.76% (95%CI: -7.74%, -3.79%) to 27.4% (95%CI: 16.6%, 38.3%). The three factors associated with the largest change in probability of asthma were short birth length, carpeted floor and paternal allergy; for rhinitis they were maternal smoking during pregnancy, paternal allergy and living close to industrial area; and for wheeze they were carpeted floor, short birth length and maternal allergy. Other home environmental risk factors identified were living close to a highway, industrial area or river, sharing bedroom, cooking with gas, furry pets, cockroaches, incense, printer/photocopier, TV, damp, and window condensation in winter. Lifestyle-related risk factors were child caretakers other than parents, and age<3 for the day-care. Other risk factors included use of antibiotics, and mother's occupation. Major protective factors for wheeze were living in a rural/suburban region, air conditioner use, and mother's occupation in healthcare.

CONCLUSIONS

Our findings suggest that changes in lifestyle and indoor environments associated with the urbanization and industrialization of China are associated with asthma, rhinitis, and wheeze in children.

All roads lead to inflammation: Is maternal immune activation a common culprit behind environmental factors impacting offspring neural control of breathing?

Despite numerous studies investigating how prenatal exposures impact the developing brain, there remains very little known about how these in utero exposures impact the life-sustaining function of breathing. While some exposures such as alcohol and drugs of abuse are well-known to alter respiratory function, few studies have evaluated other common maternal environmental stimuli, such as maternal infection, inhalation of diesel exhaust particles prevalent in urban areas, or obstructive sleep apnea during pregnancy, just to name a few. The goals of this review article are thus to: 1) highlight data on gestational exposures that impair respiratory function, 2) discuss what is known about the potential role of inflammation in the effects of these maternal exposures, and 3) identify less studied but potential in utero exposures that could negatively impact CNS regions important in respiratory motor control, perhaps by impacting maternal or fetal inflammation. We highlight gaps in knowledge, summarize evidence related to the possible contributions of inflammation, and discuss the need for further studies of life-long offspring respiratory function both at baseline and after respiratory challenge.

Review of the effect of air pollution exposure from industrial point sources on asthma-related effects in childhood

We reviewed epidemiologic studies of the association between exposure to air pollution from industries and asthma-related outcomes in childhood. We searched bibliographic databases and reference lists of relevant articles to identify studies examining the association between children's exposure to air pollution from industrial point-sources and asthma-related outcomes, including asthma, asthma-like symptoms, wheezing, and bronchiolitis. We extracted key characteristics of each study and when appropriate we performed a random-effects meta-analysis of results and quantified heterogeneity (I ²). Thirty-six studies were included in this review. Meta-analysis was generally not possible and limited to a few studies because of substantial variation across design characteristics and methodologies. In case-crossover studies using administrative health data, pooled odds ratio (OR) of hospitalization for asthma and bronchiolitis in children <5 years were 1.02 [95% confidence intervals (CI): 0.96, 1.08; I ² = 56%] and 1.01 (95% CI: 0.97, 1.05; I ² = 64%) per 10 ppb increase in the daily mean and hourly maximum concentration of sulfur dioxide (SO₂), respectively. For PM_2.5, pooled ORs were 1.02 (95% CI: 0.93, 1.10; I ² = 56%) and 1.01 (95% CI: 0.98, 1.03 I ² = 33%) per 10 μg/m³ increment in the daily mean and hourly maximum concentration. In cross-sectional studies using questionnaires, pooled ORs for the prevalence of asthma and wheezing in relation to residential proximity to industry were 1.98 (95% CI: 0.87, 3.09; I ² =71%) and 1.33 (95% CI: 0.86, 1.79; I ²= 65%), respectively. In conclusion, this review showed substantial heterogeneity across study designs and methods. Meta-analysis results suggested no evidence of an association for short-term asthma-related effects and an indication for long-term effects, but heterogeneity between results and limitations in terms of design and exposure assessment preclude drawing definite conclusions. Further well-conducted studies making use of a longitudinal design and of refined exposure assessment methods are needed to improve risk estimates.

GIS based evaluation of social determinants of children's health in Turkey: Case study of Istanbul

Basic elements considered as social determinants of the health varies in political, socio-economic, structural and intermediary contexts. While socio-economic and political contexts are directly related with the social, economic, public and health policies in country scale. The structural context additionally includes socio-economic dimensions such as income, education, occupation, social class, gender and race/ethnicity. In addition to these basic determinants, the public health, and especially the children health is also affected by the intermediary determinants, which are material circumstances including physical conditions of the working, housing and neighborhood environments and consumption potential (i.e. healthy foods, proper clothing etc.). Existing experiences provided that, the children who grow up on low socioeconomic conditions or on inappropriate environmental conditions including the residential structures tend to become more often ill than the children living in better environmental and socio-economic conditions. This situation reveals the importance of the city planning in terms of providing better conditions for children's health. This study aims to evaluate the social determinants of children's health by the use of Geographic Information System (GIS) technology. For this purpose, a variety of social determinants in terms of political (quality and quantity of health services), structural (education and social class) and intermediary (physical environment, housing, and neighborhood) contexts were examined in Bakırköy and Esenler districts, which are located European side of Istanbul. For this purpose, 2017 dated official dataset including census information and the statistics on the quality and the quantity of the education and health services in two districts were used for examining the political and structural determinants. The spatial characteristics of the physical environment and housing conditions in the study area were constructed from cadastral maps and development plans by use of GIS tools. As a last step, children's health data that consists of pediatric patient visits and diagnosis reports from 12 hospitals in Bakırköy and Esenler districts were also examined for understanding the potential relationships between the social determinants and existing health conditions. Results of this research revealed that the Bakırköy district has better conditions in terms of all health determinants when compared with Esenler district. Therefore, the health status of children living in Bakirköy is expected to be better than those living in the Esenler, which coincides with the evaluation of official children health data.

Metal-containing Particulate Matter and Associated Reduced Olfactory Identification Ability in Children from an Area of High Atmospheric Exposure in Mexico City

Air pollution has been linked to poor olfactory function in human adults. Among pollutants, particulate matter (PM) is especially relevant, as it may contain toxic metal ions that can reach the brain via olfactory pathways. Our purpose was to investigate the relation between atmospheric PM and olfactory identification performance in children. Using a validated method, we tested the olfactory identification performance of 120 children, 6–12 years old, from two locations in Mexico City: a focal group (n = 60) from a region with high PM levels and a control group of equal size and similar socioeconomic level from a region with markedly lower PM concentrations. Groups were matched for age and sex. Concentrations of manganese and lead in the hair of participants were determined as biomarkers of exposure. Daily outdoor PM levels were obtained from official records, and indoor PM levels were measured in the children’s classrooms. Official records confirmed higher levels of outdoor PM in the focal region during the days of testing. We also found higher classroom PM concentrations at the focal site. Children from the focal site had on average significantly lower olfactory identification scores than controls, and hair analysis showed significantly higher levels of manganese for the focal children but no difference in lead. Children appear to be vulnerable to the effects of air pollution on olfactory identification performance, and metal-containing particles likely play a role in this. Olfactory tests provide a sensitive, noninvasive means to assess central nervous function in populations facing poor air quality.

Applying a biopsychosocial model to inner city asthma: Recent approaches to address pediatric asthma health disparities

Pediatric asthma in inner cities is often severe and children living in these urban locations with socioeconomic disadvantage experience greater asthma morbidity. There are many interconnected risk factors that individually, and in combination, enhance asthma morbidity. These include biologic factors innate to the child, such as genetics and allergen susceptibility, as well as factors related to the family and neighborhood context. The biopsychosocial model can be used to frame these risk factors and develop interventions specific to the inner city. Successful inner city asthma interventions exist and key characteristics include multi-tiered components that operate within the community to coordinate disease management resources between patients, families and health care systems.

Mapping inequality: Childhood asthma and environmental injustice, a case study of St. Louis, Missouri

As a geographic continuum of poverty and affluence has emerged, so too has a geographic continuum of good and poor health. Asthma is currently one of the most prevalent chronic childhood diseases. Over the past three decades, the greatest increases in asthma rates have been in urban areas and have disproportionately affected youth in poverty and those in racial and ethnic minority groups. Neighborhoods serve as a mechanism fostering environmental injustice and perpetuating these disparities in health outcomes and life opportunity for our most vulnerable populations. Using Geographic Information Systems (GIS) methods in a case study of St. Louis Missouri, this study examines local environmental risk by identifying 'hotspots,' or statistically significant spatial clustering of high or low levels of childhood asthma, and associations with neighborhood characteristics, socio-demographic characteristics, and access to healthcare resources within these hotspots. Results revealed statistically significant clustering of high asthma rates in areas with more non-White and poor residents, higher rates of public housing, deteriorating housing, and violent crime. High asthma hotspots were also located in areas with limited physical access to healthcare resources, such as physicians and medication, and lower school attendance rates. Residents of these high asthma hotspots experience greater environmental risk, and significant disparities in health and education outcomes, physical and financial healthcare resources, and overall well-being. This study demonstrates these place-based inequalities and presents clear evidence of environmental injustice, supporting the need for investments and interventions to improve the environments, health, and economic resources of our most vulnerable youth.

Air Pollution and Noncommunicable Diseases: A Review by the Forum of International Respiratory Societies' Environmental Committee, Part 2: Air Pollution and Organ Systems

Although air pollution is well known to be harmful to the lung and airways, it can also damage most other organ systems of the body. It is estimated that about 500,000 lung cancer deaths and 1.6 million COPD deaths can be attributed to air pollution, but air pollution may also account for 19% of all cardiovascular deaths and 21% of all stroke deaths. Air pollution has been linked to other malignancies, such as bladder cancer and childhood leukemia. Lung development in childhood is stymied with exposure to air pollutants, and poor lung development in children predicts lung impairment in adults. Air pollution is associated with reduced cognitive function and increased risk of dementia. Particulate matter in the air (particulate matter with an aerodynamic diameter < 2.5 μm) is associated with delayed psychomotor development and lower child intelligence. Studies link air pollution with diabetes mellitus prevalence, morbidity, and mortality. Pollution affects the immune system and is associated with allergic rhinitis, allergic sensitization, and autoimmunity. It is also associated with osteoporosis and bone fractures, conjunctivitis, dry eye disease, blepharitis, inflammatory bowel disease, increased intravascular coagulation, and decreased glomerular filtration rate. Atopic and urticarial skin disease, acne, and skin aging are linked to air pollution. Air pollution is controllable and, therefore, many of these adverse health effects can be prevented.

Childhood respiratory allergies and symptoms in highly polluted area of Central Europe

The study investigated the associations between the prevalence of the childhood respiratory diseases and the long-term exposure to air pollution in the burdened area of Moravian-Silesian Region in the Czech Republic. The health data were collected during 2014 in 7,239 children 5, 9, 13 and 17 years of age. Exposure to PM₁₀ and NO₂ in the residence addresses was based on dispersion models and GIS based traffic-related indicators. PM₁₀ levels were positively associated with both lifetime (OR 1.35; 95%CI 1.09-1.67) and current (OR 1.32; 95%CI 1.05-1.67) allergic rhinitis; current asthma was associated negatively. The associations between traffic indicator and respiratory health were not found. On the other hand, marked positive associations were found between the respiratory diseases and symptom severity structured into ordinal variables, and PM₁₀ and NO₂. Modelled long-term exposure to air pollution was associated with childhood allergic rhinitis and deterioration of the respiratory symptoms.

Air pollution, urgent asthma medical visits and the modifying effect of neighborhood asthma prevalence

BACKGROUND

Social and environmental stressors may modify associations between environmental pollutants and asthma symptoms. We examined if neighborhood asthma prevalence (higher: HAPN vs. lower: LAPN), a surrogate for underlying risk factors for asthma, modified the relationship between pollutants and urgent asthma visits.

METHODS

Through zip code, home addresses were linked to New York City Community Air Survey's land use regression model for street-level, annual average nitrogen dioxide (NO2), particulate matter (PM2.5), elemental carbon (EC), summer average ozone (O3), winter average sulfur dioxide (SO2) concentrations. Poisson regression models were fit to estimate the association (prevalence ratio, PR) between pollutant exposures and seeking urgent asthma care.

RESULTS

All pollutants, except O3 were higher in HAPN than LAPN (P < 0.01). Neighborhood asthma prevalence modified the relationship between pollutants and urgent asthma (P-interaction < 0.01, for NO2 and SO3). Associations between pollutants and urgent asthma were observed only in LAPN (NO2: PR = 1.38, P = 0.01; SO3: PR = 1.85, P = 0.04). No association was observed between pollutants and urgent asthma among children in HAPN (P > 0.05).

CONCLUSIONS

Relationships between modeled street-level pollutants and urgent asthma were stronger in LAPN compared to HAPN. Social stressors that may be more prevalent in HAPN than LAPN, could play a greater role in asthma exacerbations in HAPN vs. pollutant exposure alone.

The Use of Geographic Data to Improve Asthma Care Delivery and Population Health

The authors examine uses of geographic data to improve asthma care delivery and population health and describe potential practice changes and areas for future research.

Change over time of the mutagenicity in the lungs of gpt delta transgenic mice by extract of airborne particles collected from ambient air in the Tokyo metropolitan area

BACKGROUND

Previously we found that DNA adducts were accumulated in the lungs of the rats exposed to ambient air in the Tokyo metropolitan area. To examine chronological change in in vivo mutagenicity of airborne particles, extracts produced from samples of total suspended particulates (TSP) collected from urban air in 1980, 1990, and 2010 in the Tokyo metropolitan area were intratracheally administered into the lungs of gpt delta mice, and differences in mutation and mutant frequency were determined by using the gpt assay. In vivo mutations induced by the extracts were characterized and mutation hotspots were identified by DNA sequencing of the mutated gpt gene.

RESULTS

Administration of the 1990 extract at a dose of 0.3 mg/animal significantly elevated total mutant frequency to 3.3-times that in vehicle control, and the in vivo mutagenicity of the extract (induced mutation frequency per milligram extract) was estimated to be 2.0- and 2.4-times higher than that of the 2010 and 1980 extract, respectively. G-to-A transition was the most common base substitution in the vehicle control mice. However, administration of the 1990 extract increased the frequency of G-to-T transversion, which is a landmark base substitution induced by oxidative stress; furthermore, when the extract was administered at a dose of 0.15 mg, the mutant and mutation frequencies of G-to-T transversion were significantly increased to frequencies comparable with those of G-to-A transition. Similar increases in the mutant and mutation frequencies of G-to-T transversion were observed after administration of the 2010 extract. Hotspots (mutation foci identified in three or more mice) of G-to-A transition mutations at nucleotides 64 and 110 were induced by the 1980, 1990, and 2010 extracts; a hotspot of G-to-T transversions at nucleotide 406 was also induced by the 2010 extract. Previously, we showed that diesel exhaust particles or their extract, as well as 1,6-dinitropyrene, administered to mice induced these hotspots of G-to-A transitions.

CONCLUSIONS

The results of the present study suggested that mutagenesis induced by extracts produced from TSP collected in the Tokyo metropolitan area induced in vivo mutagenicity via the same mechanism underlying the induction of in vivo mutagenicity by components of diesel exhaust.

Effects of Migration on Allergic Diseases

Studies in migrant populations provide vital opportunities to investigate the role of environmental factors in the pathogenesis of allergic disorders. Differences in allergy prevalence have been observed between migrants and native-born subjects living in the same geographical location. Immigrants who migrate from less affluent countries with lower allergy prevalence tend to have a lower prevalence of allergic disorders compared to native-born residents of the more affluent host country. The patterns of allergic disease prevalence also differ between first- and second-generation migrants. The timing of migration in relation to birth, age at migration, and duration of residence in the host country also influence one's atopic risk. A complex interplay of multiple environmental, socioeconomic, and cultural factors is likely responsible for these observed differences. Further research into the roles of various risk factors in modulating differences in allergic disease prevalence between migrant and native populations will enhance our understanding of the complex gene-environment interactions involved in the pathogenesis of allergic disorders.

Air pollutants and early origins of respiratory diseases

Air pollution is a global health threat and causes millions of human deaths annually. The late onset of respiratory diseases in children and adults due to prenatal or perinatal exposure to air pollutants is emerging as a critical concern in human health. Pregnancy and fetal development stages are highly susceptible to environmental exposure and tend to develop a long-term impact in later life. In this review, we briefly glance at the direct impact of outdoor and indoor air pollutants on lung diseases and pregnancy disorders. We further focus on lung complications in later life with early exposure to air pollutants. Epidemiological evidence is provided to show the association of prenatal or perinatal exposure to air pollutants with various adverse birth outcomes, such as preterm birth, lower birth weight, and lung developmental defects, which further associate with respiratory diseases and reduced lung function in children and adults. Mechanistic evidence is also discussed to support that air pollutants impact various cellular and molecular targets at early life, which link to the pathogenesis and altered immune responses related to abnormal respiratory functions and lung diseases in later life.

Modelling the asthma phenotype: impact of cigarette smoke exposure

Background

Asthmatics that are exposed to inhaled pollutants such as cigarette smoke (CS) have increased symptom severity. Approximately 25% of adult asthmatics are thought to be active smokers and many sufferers, especially in the third world, are exposed to high levels of inhaled pollutants. The mechanism by which CS or other airborne pollutants alter the disease phenotype and the effectiveness of treatment in asthma is not known. The aim of this study was to determine the impact of CS exposure on the phenotype and treatment sensitivity of rodent models of allergic asthma.

Methods

Models of allergic asthma were configured that mimicked aspects of the asthma phenotype and the effect of CS exposure investigated. In some experiments, treatment with gold standard asthma therapies was investigated and end-points such as airway cellular burden, late asthmatic response (LAR) and airway hyper-Reactivity (AHR) assessed.

Results

CS co-exposure caused an increase in the LAR but interestingly attenuated the AHR. The effectiveness of LABA, LAMA and glucocorticoid treatment on LAR appeared to be retained in the CS-exposed model system. The eosinophilia or lymphocyte burden was not altered by CS co-exposure, nor did CS appear to alter the effectiveness of glucocorticoid treatment. Steroids, however failed to reduce the neutrophilic inflammation in sensitized mice exposed to CS.

Conclusions

These model data have certain parallels with clinical findings in asthmatics, where CS exposure did not impact the anti-inflammatory efficacy of steroids but attenuated AHR and enhanced symptoms such as the bronchospasm associated with the LAR. These model systems may be utilised to investigate how CS and other airborne pollutants impact the asthma phenotype; providing the opportunity to identify novel targets.

Environmental exposures and fetal growth: the Haifa pregnancy cohort study

Background

The developing fetus is susceptible to environmental insults. Studying the effects of environmental exposures on fetal growth is essential for understanding the causal pathway between prenatal exposures and pregnancy outcomes. Here we describe the Haifa Pregnancy Cohort Study (HPCS) and discuss challenges and opportunities in applying “big data” paradigm.

Methods

Maccabi Healthcare Services (MHS), is the second largest Israeli health maintenance organization (HMO) providing care services to two million beneficiaries. The HPCS cohort potentially includes ~750,000 newborns born between 1998 and 2017. We will estimate daily exposures to air pollutants, temperature and greenness, using satellite-based data and models. We hypothesize that residents of Haifa have higher exposures to environmental pollutants and that in pregnant women this higher exposure is associated with poorer fetal growth. We will evaluate outcomes such as birth-weight, head-circumference and gestational age at birth. We will adjust for pregnancy complications such as pre-eclampsia and gestational diabetes and parental variables, such as maternal weight, age and smoking habits as potential confounders. In addition, we will conduct a multi-tiered field study, nested within this population, among 150 pregnant women residing in two geographical regions-one in the polluted Haifa area, and one in a relatively unpolluted area in central Israel. Blood and urinary samples will be collected, as well as personal and indoor exposure to air pollution.

Discussion

Evaluating environmental exposures of pregnant women and assessing in utero growth over the course of the pregnancy during different exposure windows, is of great scientific and public health interest. Recent advances in data collection and analysis pose great promise to provide insights into contribution of environment to the health of the developing fetus, but also pose major challenges and pitfalls, such as data management, proper statistical framework and integration of data in the population-based study and selectiveness in the nested field study. Yet the continuing follow-up of the study cohort, integrating data from different services, health-promotion, and eventually, application later in real life of our main promises. Our study aims to meet these challenges and to provide evidence of the environmental exposures associated with fetal growth.

The effects of PM2.5 on asthmatic and allergic diseases or symptoms in preschool children of six Chinese cities, based on China, Children, Homes and Health (CCHH) project

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/m³ 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.

The impact of prenatal exposure to air pollution on childhood wheezing and asthma: A systematic review

BACKGROUND AND OBJECTIVES

There has been no clear consensus about whether prenatal exposure to air pollution contributes to the development of wheezing and asthma in children. We conducted a systematic review to analyze the association between exposure to different pollutants during pregnancy and the development of childhood wheezing and asthma.

METHODS

We systematically reviewed epidemiological studies published through June 6, 2017 available in the MEDLINE and Web of Science databases. We included studies that examined the association between prenatal exposure to any air pollutants except tobacco smoke and the incidence or prevalence of "wheezing" or "asthma" from birth to 14 years of age. We extracted key characteristics of each included study using a template of predefined data items. We used the Critical Appraisal Skills Programme checklists to assess the validity of each included study. We conducted overall and subgroup meta-analyses for each summary exposure-outcome association. Pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated by using a random effects model.

RESULTS

Eighteen studies met our eligibility criteria. There was notable variability in exposure assessment methods. The overall random effects risk estimates (95% CI) of different pollutants were 1.04 (0.94-1.15) aromatic hydrocarbons (PAH), 1.04 (1.01-1.07) NO₂, 1.4 (0.97-2.03) PM_2.5 for childhood wheeze and 1.07 (1.01-1.14) NO₂, 1 (0.97-1.03) PM_2.5, 1.02 (0.98-1.07) SO₂, 1.08 (1.05-1.12) PM₁₀ for childhood asthma. Minimal heterogeneity was seen for PAH and SO₂, while some heterogeneity was observed for PM₁₀, PM_2.5 and NO₂.

CONCLUSIONS

The overall and subgroup risk estimates from the meta-analyses showed statistically significant associations between prenatal exposures to NO₂, SO₂, and PM₁₀ and the risk of wheezing and asthma development in childhood. There is insufficient evidence to show an effect of prenatal exposure to BC, CO, and O₃ on childhood wheezing and asthma. Further studies are needed to examine the individual compounds' effects.

Short-term effects of ambient air pollution on pediatric outpatient visits for respiratory diseases in Yichang city, China

Previous studies have suggested that short-term exposure to ambient air pollution was associated with pediatric hospital admissions and emergency room visits for certain respiratory diseases; however, there is limited evidence on the association between short-term air pollution exposure and pediatric outpatient visits. Our aim was to quantitatively assess the short-term effects of ambient air pollution on pediatric outpatient visits for respiratory diseases. We conducted a time-series study in Yichang city, China between Jan 1, 2014 and Dec 31, 2015. Daily counts of pediatric respiratory outpatient visits were collected from 3 large hospitals, and then linked with air pollution data from 5 air quality monitoring stations by date. We used generalized additive Poisson models to conduct linear and nonlinear exposure-response analyses between air pollutant exposures and pediatric respiratory outpatient visits, adjusting for seasonality, day of week, public holiday, temperature, and relative humidity. Each interquartile range (IQR) increase in PM_2.5 (lag 0), PM₁₀ (lag 0), NO₂ (lag 0), CO (lag 0), and O₃ (lag 4) concentrations was significantly associated with a 1.91% (95% CI: 0.60%, 3.23%), 2.46% (1.09%, 3.85%), 1.88% (0.49%, 3.29%), 2.00% (0.43%, 3.59%), and 1.91% (0.45%, 3.39%) increase of pediatric respiratory outpatient visits, respectively. Similarly, the nonlinear exposure-response analyses showed monotonic increases of pediatric respiratory outpatient visits by increasing air pollutant exposures, though the associations for NO₂ and CO attenuated at higher concentrations. These associations were unlikely modified by season. We did not observe significant association for SO₂ exposure. Our results suggest that short-term exposures to PM_2.5, PM₁₀, NO₂, CO, and O₃ may account for increased risk of pediatric outpatient visits for respiratory diseases, and emphasize the needs for reduction of air pollutant exposures for children.

Allergic disease associations with regional and localized estimates of air pollution

BACKGROUND

Exposure to multiple types of air pollution may contribute to and exacerbate allergic diseases including asthma and wheezing. However, few studies have examined chronic air pollution exposure and allergic disease outcomes among an adult population. Associations between potential estimates of annual average fine particulate matter (PM2.5), traffic related air pollution, and industrial source air emissions and three allergic disease outcomes (asthma, allergies and wheezing) were examined in a state-wide general population of adults.

METHODS

The study includes a representative sample of 3381 adult Wisconsin residents who participated in the 2008-2013 Survey of the Health of Wisconsin (SHOW) program. Participant data were geographically linked to The United States Environmental Protection Agency (USEPA) Baysian space-time downscaler air pollution model for PM2.5, the United States Census roadway, and USEPA's Toxic Release Inventory data. Self-report and lung function (FEV1) estimates were used to define prevalence of asthma, allergies and wheezing symptoms.

RESULTS

Annual mean exposure to fine particulate matter (PM2.5) was between 6.59 and 15.14μg/m3. An increase of 5μg/m3 in the annual mean PM2.5 resulted in a 3.58 (2.36, 5.43) increase in the adjusted odds (95% CI) of having asthma. Exposure to vehicle traffic increased the odds of both current allergies [OR (95% CI)=1.35 (1.07, 1.35)] and current asthma [OR (95% CI)=1.51 (1.14, 2.00)]. Living within 300m of an Interstate roadway was associated with a 3-fold increase in the odds of asthma. Those living within 800m of an industrial site were 47% more likely to have asthma. No significant associations were seen with wheezing.

CONCLUSIONS

Within this population exposed to overall annual average levels of estimated low level chronic exposure to fine particulate matter (PM2.5) at or near 12μg/m3, the USEPA standard for air quality, significant association between both modeled PM2.5 exposure and proximity to roadways with asthma and allergies but not wheezing were found. Industrial source emissions were not associated with any allergic disease outcomes.

Air pollution, PM2.5 composition, source factors, and respiratory symptoms in asthmatic and nonasthmatic children in Santiago, Chile

The objective of this study was to determine the association of respiratory symptoms and medication use and exposure to various air pollutants, PM_2.5 components, and source factors in a panel of asthmatic and nonasthmatic children in Santiago, Chile. To this end, 174 children (90 asthmatics and 84 nonasthmatics) were followed throughout the winter months of 2010 and 2011. During the study period, children filled out daily diaries to record respiratory symptoms and medication use. Air pollution data were obtained from government central site measurements and a PM_2.5 characterization campaign. PM_2.5 source factors were obtained using positive matrix factorization (PMF). Associations of symptoms and exposure to pollutants and source-factor daily scores were modeled separately for asthmatic and nonasthmatic children using mixed logistic regression models with random intercepts, controlling for weather, day of the week, year, and viral outbreaks. Overall, high concentrations of air pollutants and PM_2.5 components were observed. Six source factors were identified by PMF (motor vehicles, marine aerosol, copper smelter, secondary sulfates, wood burning, and soil dust). Overall, single pollutant models showed significant and strong associations between 7-day exposures for several criteria pollutants (PM_2.5, NO₂, O₃), PM_2.5 components (OC, K, S, Se, V), and source factors (secondary sulfate) and coughing, wheezing and three other respiratory symptoms in both in asthmatic and nonasthmatic children. No associations were found for use of rescue inhalers in asthmatics. Two-pollutant models showed that several associations remained significant after including PM_2.5, and other criteria pollutants, in the models, particularly components and source factors associated with industrial sources. In conclusion, exposure to air pollutants, especially PM_2.5, NO₂, and O₃, were found to exacerbate respiratory symptoms in both asthmatic and nonasthmatic children. Some of the results suggest that PM_2.5 components associated with a secondary sulfate source may have a greater impact on some symptoms than PM_2.5. In general, the results of this study show important associations at concentrations close or below current air quality standards.

Evaluation of in vivo mutagenesis for assessing the health risk of air pollutants

Various kind of chemical substances, including man-made chemical products and unintended products, are emitted to ambient air. Some of these substances have been shown to be mutagenic and therefore to act as a carcinogen in humans. National pollutant inventories (e.g., Pollutant Release and Transfer Registration in Japan) have estimated release amounts of man-made chemical products, but a major concern is the release of suspended particulate matter containing potent mutagens, for example, polycyclic aromatic hydrocarbons and related compounds generated by the combustion of fossil fuel, which are not estimated by PRTR system. In situ exposure studies have revealed that DNA adducts in the lung, and possibly mutations in germline cells are induced in rodents by inhalation of ambient air, indicating that evaluating in vivo mutations is important for assessing environmental health risks. Transgenic rodent systems (Muta, Big Blue, and gpt delta) are good tools for analyzing in vivo mutations induced by a mixture of chemical substances present in the environment. Following inhalation of diesel exhaust (used as a model mixture), mutation frequency was increased in the lung of gpt delta mice and base substitutions were induced at specific guanine residues (mutation hotspots) on the target transgenes. Mutation hotspots induced by diesel exhaust were different from those induced by benzo[a]pyrene, a typical mutagen in ambient air, but nearly identical to those induced by 1,6-dinitropyrene contained in diesel exhaust. Comparison between mutation hotspots in the TP53 (p53) gene in human lung cancer (data extracted from the IARC TP53 database) and mutations we identified in gpt delta mice showed that G to A transitions centered in CGT and CGG trinucleotides were mutation hotspots on both TP53 genes in human lung cancers and gpt genes in transgenic mice that inhaled diesel exhaust. The carcinogenic potency (TD50 value) of genotoxic carcinogen was shown to be correlated with the in vivo mutagenicity (total dose per increased mutant frequency). These results suggest that the mutations identified in transgenic rodents can help identify environmental mutagens that cause cancer.

Traffic-Related Air Pollution and Childhood Asthma: Recent Advances and Remaining Gaps in the Exposure Assessment Methods

Background: Current levels of traffic-related air pollution (TRAP) are associated with the development of childhood asthma, although some inconsistencies and heterogeneity remain. An important part of the uncertainty in studies of TRAP-associated asthma originates from uncertainties in the TRAP exposure assessment and assignment methods. In this work, we aim to systematically review the exposure assessment methods used in the epidemiology of TRAP and childhood asthma, highlight recent advances, remaining research gaps and make suggestions for further research. Methods: We systematically reviewed epidemiological studies published up until 8 September 2016 and available in Embase, Ovid MEDLINE (R), and “Transport database”. We included studies which examined the association between children’s exposure to TRAP metrics and their risk of “asthma” incidence or lifetime prevalence, from birth to the age of 18 years old. Results: We found 42 studies which examined the associations between TRAP and subsequent childhood asthma incidence or lifetime prevalence, published since 1999. Land-use regression modelling was the most commonly used method and nitrogen dioxide (NO₂) was the most commonly used pollutant in the exposure assessments. Most studies estimated TRAP exposure at the residential address and only a few considered the participants’ mobility. TRAP exposure was mostly assessed at the birth year and only a few studies considered different and/or multiple exposure time windows. We recommend that further work is needed including e.g., the use of new exposure metrics such as the composition of particulate matter, oxidative potential and ultra-fine particles, improved modelling e.g., by combining different exposure assessment models, including mobility of the participants, and systematically investigating different exposure time windows. Conclusions: Although our previous meta-analysis found statistically significant associations for various TRAP exposures and subsequent childhood asthma, further refinement of the exposure assessment may improve the risk estimates, and shed light on critical exposure time windows, putative agents, underlying mechanisms and drivers of heterogeneity.

Exposure to traffic-related air pollution and risk of development of childhood asthma: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The question of whether children's exposure to traffic-related air pollution (TRAP) contributes to their development of asthma is unresolved. We conducted a systematic review and performed meta-analyses to analyze the association between TRAP and asthma development in childhood.

DATA SOURCES

We systematically reviewed epidemiological studies published until 8 September 2016 and available in the Embase, Ovid MEDLINE (R), and Transport databases.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included studies that examined the association between children's exposure to TRAP metrics and their risk of 'asthma' incidence or lifetime prevalence, from birth to age 18years old.

STUDY APPRAISAL AND SYNTHESIS METHODS

We extracted key characteristics of each included study using a predefined data items template and these were tabulated. We used the Critical Appraisal Skills Programme checklists to assess the validity of each included study. Where four or more independent risk estimates were available for a continuous pollutant exposure, we conducted overall and age-specific meta-analyses, and four sensitivity analyses for each summary meta-analytic exposure-outcome association.

RESULTS

Forty-one studies met our eligibility criteria. There was notable variability in asthma definitions, TRAP exposure assessment methods and confounder adjustment. The overall random-effects risk estimates (95% CI) were 1.08 (1.03, 1.14) per 0.5×10^-5m^-1 black carbon (BC), 1.05 (1.02, 1.07) per 4μg/m³ nitrogen dioxide (NO₂), 1.48 (0.89, 2.45) per 30μg/m³ nitrogen oxides (NO_x), 1.03 (1.01, 1.05) per 1μg/m³ Particulate Matter <2.5μm in diameter (PM_2.5), and 1.05 (1.02, 1.08) per 2μg/m³ Particulate Matter <10μm in diameter (PM₁₀). Sensitivity analyses supported these findings. Across the main analysis and age-specific analysis, the least heterogeneity was seen for the BC estimates, some heterogeneity for the PM_2.5 and PM₁₀ estimates and the most heterogeneity for the NO₂ and NO_x estimates.

LIMITATIONS, CONCLUSIONS AND IMPLICATION OF KEY FINDINGS

The overall risk estimates from the meta-analyses showed statistically significant associations for BC, NO₂, PM_2.5, PM₁₀ exposures and risk of asthma development. Our findings support the hypothesis that childhood exposure to TRAP contributes to their development of asthma. Future meta-analyses would benefit from greater standardization of study methods including exposure assessment harmonization, outcome harmonization, confounders' harmonization and the inclusion of all important confounders in individual studies.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO 2014: CRD42014015448.

Exposure estimation errors to nitrogen oxides on a population scale due to daytime activity away from home

Accurate estimation of exposure to air pollution is necessary for assessing the impact of air pollution on the public health. Most environmental epidemiology studies assign the home address exposure to the study subjects. Here, we quantify the exposure estimation error at the population scale due to assigning it solely at the residence place. A cohort of most schoolchildren in Israel (~950,000), age 6-18, and a representative cohort of Israeli adults (~380,000), age 24-65, were used. For each subject the home and the work or school addresses were geocoded. Together, these two microenvironments account for the locations at which people are present during most of the weekdays. For each subject, we estimated ambient nitrogen oxide concentrations at the home and work or school addresses using two air quality models: a stationary land use regression model and a dynamic dispersion-like model. On average, accounting for the subjects' work or school address as well as for the daily pollutant variation reduced the estimation error of exposure to ambient NO_x/NO₂ by 5-10ppb, since daytime concentrations at work/school and at home can differ significantly. These results were consistent regardless which air quality model as used and even for subjects that work or study close to their home. Yet, due to their usually short commute, assigning schoolchildren exposure solely at their residential place seems to be a reasonable estimation. In contrast, since adults commute for longer distances, assigning exposure of adults only at the residential place has a lower correlation with the daily weighted exposure, resulting in larger exposure estimation errors. We show that exposure misclassification can result from not accounting for the subjects' time-location trajectories through the spatiotemporally varying pollutant concentrations field.

Population Epigenetics

The field of epigenetics is maturing, with increased interest in understanding the normal regulation of the genome and the possibility that it becomes reprogrammed aberrantly as part of the cause of disease phenotypes. Applying the current technologies and insights to the study of human populations is potentially a way of understanding mechanisms and consequences of these diseases. When extended to encompass health care disparities, understanding why certain populations are unusually prone to specific conditions, there is certainly some potential for gaining new and valuable insights, but these studies are likely to be unusually prone to the effects of confounding influences and need to be designed, executed and interpreted with extra care.