Early childhood traffic-related air pollution and risk of allergic rhinitis at 2-4 years of age modification by family stress and male gender: a case-control study in Shenyang, China

Macrophage-mediated activation of the IL4I1/AhR axis is a key player in allergic rhinitis

BACKGROUND

Epidemiological evidence suggests that environmental pollutants precipitate the occurrence of allergic rhinitis (AR). The aryl hydrocarbon receptor (AhR), a receptor or sensor for various contaminants, is closely related to immunomodulation and the polarization of M2 macrophages. However, the mechanisms involving AhR and M2 macrophages in AR remain unclear.

METHODS

Bioinformatics analysis of GEO datasets (GSE180697 and GSE180697) assessed AhR and IL4I1 expression levels, which were then verified in the nasal mucosa, monocytes and serum of patients with AR using western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Primary human mononuclear cells were isolated from peripheral blood using a magnetic separation technique, and THP-1 cell lines with IL4I1 overexpression or downexpression were established through lentiviral constructs. M2 macrophages were induced with the cytokines CSF, IL4 and IL13 and then treated with the AhR agonist FICZ or inhibitor CH223191. The polarization of M2 macrophages was measured by flow cytometry and western blotting. Furthermore, primary nasal epithelial cells and macrophages were co-cultured to assess the epithelial-mesenchymal transition (EMT) in epithelial cells. The AR murine model was established using ovalbumin (OVA). Inflammation within the nasal mucosa and lung tissue was examined after CH223191 or IL4I1 treatment.

RESULTS

Nuclear translocation of AhR and upregulation of IL4I1 was observed in peripheral mononuclear cells and nasal mucosal tissue of patients with AR. Through the activation of AhR, IL4I1 promoted M2 macrophage polarization. Furthermore, modulation of the IL4I1/AhR axis regulated the migratory impact of OVA on T-M2 cells. The IL4I1/AhR axis was involved in the regulation of M2 macrophage-associated EMT and contributed to the expression of IL-33 and STAT6 phosphorylation in epithelial cells. In AR mice, increased AhR nuclear translocation and higher expression of IL4I1 and the M2 macrophage marker CD206 in the lungs was observed. The IL4I1/AhR axis exacerbated allergic symptoms in AR mice, fostering allergic inflammation within the nasal mucosa and lungs.

CONCLUSIONS

The IL4I1/AhR axis is activated within the mononuclear phagocyte system of patients with AR. This activation facilitates the polarization of mononuclear cells into M2 macrophages, which further aggravates EMT in epithelial cells and exacerbates inflammation in AR. This study may provide novel strategies for the precise treatment of AR.

Short-term association between ambient air pollution and childhood non-allergic rhinitis: A time-series study at a National Children's Regional Medical Center, in Hefei, China, from 2015 to 2021

The relationship between air pollution exposure and non-allergic rhinitis (NAR) risk in children is underexplored and uncertain. Therefore, the impact of numerous air pollutants on the incidence of NAR in a Chinese pediatric population were investigated. Data on daily outpatient visits for NAR among children aged 0-18 years from 2015 to 2021 were obtained from Anhui Provincial Children's Hospital. A quasi-Poisson generalized linear regression model combined with a distributed lag nonlinear model was applied to evaluate the association between air pollution and outpatient visits for childhood NAR. A total of 38233 NAR outpatients were included and a positive association and cumulative effects between air pollution and childhood NAR were observed. The relative risks (RRs) and 95 % confidence intervals (95 % CIs) for childhood NAR at the 75th percentile of NO2, SO2, PM10, PM2.5, O3, and CO against their minimum concentrations were 1.157 (95 % CI: 1.089, 1.23), 1.078 (1.005, 1.157), 1.168 (1.089, 1.252), 1.076 (1.02, 1.136), 1.033 (0.961, 1.11) and 1.07 (1.01, 1.134), respectively. The cumulative effects of the air pollutants were pronounced, which was much higher than each single effects. Furthermore, the risk estimates for childhood NAR during the cold season were higher than those in the warm season. Lastly, boys and school children were found to be more vulnerable to air pollutants than girls and preschool children. All these findings suggest that air pollutants have adverse effects on childhood NAR, even at levels below those recommended by the air quality guidelines. Our study results highlight the significance of paying attention to the effects of air pollutants to prevent NAR occurrence, particularly in boys and school children and during the cold season. Therefore, stronger control measures to mitigate air pollution must be implemented to decrease NAR incidence in the pediatric population.

Associations of exposure to outdoor PM2.5 and NO2 during pregnancy with childhood asthma, rhinitis, and eczema in a predominantly rural French mother-child cohort

Uncertainty remains regarding the effects of outdoor air pollution in rural areas on childhood asthma, rhinitis, and eczema. Although these diseases often coexist, few studies have examined the effects of air pollution on their multimorbidity. The objective of this study was to investigate the associations of pregnancy exposure to outdoor fine particulate matter (PM2.5) and nitrogen dioxide (NO2) with childhood asthma, rhinitis, eczema, and their multimorbidity. We included children from the 6-year (n = 1322) and 12-year (n = 1118) follow-up of the Pélagie mother-child cohort in Brittany, France where 64% of the participants lived in rural areas. Asthma, rhinitis, eczema, and a multimorbidity phenotype (concomitant presence of ≥2 diseases) were defined by validated questionnaires. PM2.5 and NO2 concentrations during pregnancy were modeled at residential address using land use regression. We assessed associations using logistic regressions per interquartile range (PM2.5: 3 μg/m3; NO2: 10 μg/m3). We also performed stratification by type of area (urban and rural). Asthma, rhinitis, eczema, and the multimorbidity phenotype prevalence were 12%, 20%, 22% and 12% at 6-years, and 10%, 23%, 19% and 11% at 12-years of follow-up. At 6-years, for eczema, a tendency of an association was observed with NO2 (OR = 1.15, 95% CI = 0.97-1.36, p-value = 0.10), and stratification by type of area showed statistically significant associations for PM2.5 (1.49 (1.03-2.13), p = 0.03) and NO2 (1.40 (1.08-1.82), p = 0.01) in the urban stratum. At 12-years, main analyses showed a tendency of associations of PM2.5 (1.38 (0.98-1.93), p = 0.07) and NO2 (1.25 (0.98-1.59), p = 0.07) with asthma, and of NO2 with the multimorbidity phenotype (1.23 (0.97-1.56), p = 0.09). While overall results were not statistically significant, associations in urban settings were stronger than in rural ones at 6-years suggesting that possible differences between the effects in urban and rural areas should be further explored.

Comorbid asthma is associated with rhinitis severity in children exposed to air pollutants

BACKGROUND

The impact of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied.

METHODS

Children with AR (65 with asthma, 208 without asthma), aged 6-13 years, were recruited from a hospital in Taichung, Taiwan, between 2007 and 2011. Correlations between Pediatric-Rhinoconjunctivitis-Quality-of-Life score, nasal peak expiratory flow, and air pollutants were compared. With the same age, research time, and form the same city, children with AR (660 with asthma, 3174 without asthma) were selected from a database. Correlations between clinical visit times for AR and air pollutants were compared.

RESULTS

In male children with AR and asthma, both clinical and database studies revealed a correlation between higher rhinitis discomfort (quality-of-life score), higher visit times for AR, and higher PM10, PM2.5, NO2, NMHC concentrations. Correlations between higher nasal inflammation/obstruction (lower expiratory flow) and higher air pollutant concentrations were observed in male children with AR and asthma.

CONCLUSION

In children with AR, comorbid asthma was associated with increased rhinitis severity when they were exposed to air pollutants, and the association was only noted in males. Increased nasal obstruction/inflammation from exposure to air pollutants may be the mechanisms underlying this association.

IMPACT STATEMENT

The influence of asthma on the severity of rhinitis when children with allergic rhinitis (AR) are exposed to air pollutants has not been studied. In children with AR, the correlation between higher rhinitis discomfort, higher number of clinical visits for AR, and higher PM10, PM2.5, NO2, NMHC concentrations were only noted in those who also had asthma. The correlation was only noted in male. Comorbid asthma was associated with higher rhinitis severity when children with AR are exposed to air pollutants The association was only noted in male.

Air pollution and rhinitis

Rhinitis arises from either allergic or non-allergic inflammation of the nasal mucosa, characterized by the infiltration of inflammatory cells into the tissue and nasal secretions, along with structural alterations in the nasal mucosa. The pathways through which air pollution affects rhinitis may diverge from those affecting asthma. This article aims to review the effects of diverse air pollutants on the nose, the correlation of climate change and pollution, and how they aggravate the symptoms of patients with rhinitis.

Exploring Associations Between Short-Term Air Pollution and Daily Outpatient Visits for Allergic Rhinitis

Purpose

Many studies have reported that exposure to air pollution increases the likelihood of acquiring allergic rhinitis (AR). This study investigated associations between short-term air pollution exposure and AR outpatient visits.

Patients and Methods

The Department of Otorhinolaryngology, Affiliated Hospital of Hangzhou Normal University provided AR outpatient data from January 1, 2019 to December 31, 2021. Daily air quality information for that period was gathered from the Hangzhou Air Quality Inspection Station. We used the Poisson's generalized additive model (GAM) to investigate relationships between daily outpatient AR visits and air pollution, and investigated lag-exposure relationships across days. Subgroup analyses were performed by age (adult (>18 years) and non-adult (<18 years)) and sex (male and female).

Results

We recorded 20,653 instances of AR during the study period. Each 10 g/m3 increase in fine particulate matter (PM10 and PM2.5) and carbon monoxide (CO) concentrations was associated with significant increases in AR outpatient Visits. The relative risks (RR) were: 1.007 (95% confidence interval (CI): 1.001-1.013), 1.026 (95% CI: 1.008-1.413), and 1.019 (95% CI: 1.008-1.047). AR visits were more likely due to elevated PM2.5, PM10, and CO levels. Additionally, children were more affected than adults.

Conclusion

To better understand the possible effects of air pollution on AR, short-term exposure to ambient air pollution (PM2.5, PM10, and CO) may be linked to increased daily outpatient AR visits.

A Synopsis of Guidance for Allergic Rhinitis Diagnosis and Management From ICAR 2023

An updated edition of the International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR) has recently been published. This consensus document, which included the participation of 87 primary authors and 40 additional consultant authors, who critically appraised evidence on 144 individual topics concerning allergic rhinitis, provides guidance for health care providers using the evidence-based review with recommendations (EBRR) methodology. This synopsis highlights topical areas including pathophysiology, epidemiology, disease burden, risk and protective factors, evaluation and diagnosis, aeroallergen avoidance and environmental controls, single and combination pharmacotherapy options, allergen immunotherapy (subcutaneous, sublingual, rush, cluster), pediatric considerations, alternative and emerging therapies, and unmet needs. Based on the EBRR methodology, ICAR:AR includes strong recommendations for the treatment of allergic rhinitis: (1) for the use of newer generation antihistamines compared with first-generation alternatives, intranasal corticosteroid, intranasal saline, combination therapy with intranasal corticosteroid plus intranasal antihistamine for patients not responding to monotherapy, and subcutaneous immunotherapy and sublingual tablet immunotherapy in properly selected patients; (2) against the use of oral decongestant monotherapy and routine use of oral corticosteroids.

Environmental Exposures may Hold the Key; Impact of Air Pollution, Greenness, and Rural/Farm Lifestyle on Allergic Outcomes

PURPOSE OF REVIEW

There has been an increased prevalence of allergy. Due to this relatively rapid rise, changes in environmental exposures are likely the main contributor. In this review, we highlight literature from the last 3 years pertaining to the role of air pollution, greenness, and the rural/farm lifestyle and their association with the development of allergic sensitization, atopic dermatitis, food allergy, and allergic rhinitis in infancy and childhood. Because asthma has a more complex pathophysiology, it was excluded from this review.

RECENT FINDINGS

Recent studies support a role for air pollution, greenness, and rural/farming lifestyle influencing atopic outcomes that continue to be defined. While many studies have examined singular environmental exposures, the interconnectedness of these exposures and others points to a need for future work to consider an individual's whole exposure. Environmental exposures' influence on atopic disease development remains an ongoing and important area of study.

Association between air pollution and the prevalence of allergic rhinitis in Chinese children: A systematic review and meta-analysis

Background: Allergic rhinitis (AR) is a common chronic inflammatory disease with bothersome symptoms. However, the effect of air pollution on the prevalence of AR in children is controversial. Objective: This study aimed to investigate the association between air pollution and the prevalence of AR in Chinese children. Methods: This study, in China, included 160,356 students ages 0-18 years who completed a questionnaire about the accuracy of the International Study of Asthma and Allergies in Childhood (ISAAC). The effect of different air pollutants on the prevalence rate were evaluated by meta-analysis. Also, it evaluated the effect of different air pollutants on the prevalence rate. Results: The differences in the effects of sulfur dioxide (SO₂) exposure (combined odds ratio [OR_combined] 1.03 [95% confidence interval {CI}, 1.01-1.05]; p = 0.010) and nitrogen dioxide (NO₂) exposure (OR_combined 1.11 [95% CI, 1.05-1.18]; p = 0.0006) on the risk of childhood AR was statistically significant. The effect of particulate matter with aerodynamic diameter of <10 μm (PM₁₀) exposure on the risk of childhood AR was statistically significant (OR_combined 1.02 [95% CI, 1.01-1.03]; p < 0.001), the effect of particulate matter with aerodynamic diameter of <2.5 μm (PM_2.5) exposure on the risk of childhood AR was statistically significant (OR_combined 1.15 [95% CI, 1.03-1.29]; p = 0.02), and the effect of ozone exposure on the risk of childhood AR was not statistically significant (OR_combined 0.98 [95% CI, 0.67-1.41]; p = 0.13). Conclusion: NO₂, SO₂, PM_2.5, and PM₁₀ were associated with the prevalence of AR in Chinese children. PM_2.5 had the highest correlation with AR prevalence.

Health Outcomes in Children Associated with Prenatal and Early-Life Exposures to Air Pollution: A Narrative Review

(1) Background: The developmental origins of health and disease (DOHaD) hypothesis links adverse fetal exposures with developmental mal-adaptations and morbidity later in life. Short- and long-term exposures to air pollutants are known contributors to health outcomes; however, the potential for developmental health effects of air pollution exposures during gestation or early-childhood have yet to be reviewed and synthesized from a DOHaD lens. The objective of this study is to summarize the literature on cardiovascular and metabolic, respiratory, allergic, and neuropsychological health outcomes, from prenatal development through early childhood, associated with early-life exposures to outdoor air pollutants, including traffic-related and wildfire-generated air pollutants. (2) Methods: We conducted a search using PubMed and the references of articles previously known to the authors. We selected papers that investigated health outcomes during fetal or childhood development in association with early-life ambient or source-specific air pollution exposure. (3) Results: The current literature reports that prenatal and early-childhood exposures to ambient and traffic-related air pollutants are associated with a range of adverse outcomes in early life, including cardiovascular and metabolic, respiratory and allergic, and neurodevelopmental outcomes. Very few studies have investigated associations between wildfire-related air pollution exposure and health outcomes during prenatal, postnatal, or childhood development. (4) Conclusion: Evidence from January 2000 to January 2022 supports a role for prenatal and early-childhood air pollution exposures adversely affecting health outcomes during development. Future studies are needed to identify both detrimental air pollutants from the exposure mixture and critical exposure time periods, investigate emerging exposure sources such as wildfire, and develop feasible interventional tools.

Ambient air pollutants increase the risk of immunoglobulin E-mediated allergic diseases: a systematic review and meta-analysis

Immunoglobulin E (IgE)-mediated allergic diseases, including eczema, atopic dermatitis (AD), and allergic rhinitis (AR), have increased prevalence in recent decades. Recent studies have proved that environmental pollution might have correlations with IgE-mediated allergic diseases, but existing research findings were controversial. Thus, we performed a comprehensive meta-analysis from published observational studies to evaluate the risk of long-term and short-term exposure to air pollutants on eczema, AD, and AR in the population (per 10-μg/m3 increase in PM2.5 and PM10; per 1-ppb increase in SO2, NO2, CO, and O3). PubMed, Embase, and Web of Science were searched to identify qualified literatures. The Cochran Q test was used to assess heterogeneity and quantified with the I2 statistic. Pooled effects and the 95% confidence intervals (CIs) were used to evaluate outcome effects. A total of 55 articles were included in the study. The results showed that long-term and short-term exposure to PM10 increased the risk of eczema (PM10, RRlong = 1.583, 95% CI: 1.328, 1.888; RRshort = 1.006, 95% CI: 1.003-1.008) and short-term exposure to NO2 (RRshort = 1.009, 95% CI: 1.008-1.011) was associated with eczema. Short-term exposure to SO2 (RRshort: 1.008, 95% CI: 1.001-1.015) was associated with the risk of AD. For AR, PM2.5 (RRlong = 1.058, 95% CI: 1.014-1.222) was harmful in the long term, and short-term exposure to PM10 (RRshort: 1.028, 95% CI: 1.008-1.049) and NO2 (RRshort: 1.018, 95% CI: 1.007-1.029) were risk factors. The findings indicated that exposure to air pollutants might increase the risk of IgE-mediated allergic diseases. Further studies are warranted to illustrate the potential mechanism for air pollutants and allergic diseases.