Air pollution, genetic factors, and chronic rhinosinusitis: A prospective study in the UK Biobank.

BACKGROUND: Chronic rhinosinusitis (CRS) is a prevalent upper respiratory condition that manifests in two primary subtypes: CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). While previous studies indicate a correlation between air pollution and CRS, the role of genetic predisposition in this relationship remains largely unexplored. We hypothesized that higher air pollution exposure would lead to the development of CRS, and that genetic susceptibility might modify this association. METHODS: This cohort study involving 367,298 adult participants from the UK Biobank, followed from March 2006 to October 2021. Air pollution metrics were estimated at residential locations using land-use regression models. Cox proportional hazard models were employed to explore the associations between air pollution exposure and CRS, CRSwNP, and CRSsNP. A polygenic risk score (PRS) was constructed to evaluate the joint effect of air pollution and genetic predisposition on the development of CRS. RESULTS: We found that the risk of CRS increased under long-term exposure to PM2.5 [the hazard ratios (HRs) with 95 % CIs: 1.59 (1.26-2.01)], PM10 [1.64 (1.26-2.12)], NO2 [1.11 (1.04-1.17)], and NOx [1.18 (1.12-1.25)], respectively. These effects were more pronounced among participants with CRSwNP, although the differences were not statistically significant. Additionally, we found that the risks for CRS and CRSwNP increased in a graded manner among participants with higher PRS or higher exposure to PM2.5, PM10, or NOx concentrations. However, no multiplicative or additive interactions were observed. CONCLUSIONS: Long-term exposure to air pollution increases the risk of CRS, particularly CRSwNP underscoring the need to prioritize clean air initiatives and environmental regulations.

Evolution of nasal and olfactory infection characteristics of SARS-CoV-2 variants.

SARS-CoV-2 infection of the upper airway and the subsequent immune response are early, critical factors in COVID-19 pathogenesis. By studying infection of human biopsies in vitro and in a hamster model in vivo, we demonstrated a transition in nasal tropism from olfactory to respiratory epithelium as the virus evolved. Analyzing each variant revealed that SARS-CoV-2 WA1 or Delta infect a proportion of olfactory neurons in addition to the primary target sustentacular cells. The Delta variant possessed broader cellular invasion capacity into the submucosa, while Omicron displayed enhanced nasal respiratory infection and longer retention in the sinonasal epithelium. The olfactory neuronal infection by WA1 and the subsequent olfactory bulb transport via axon were more pronounced in younger hosts. In addition, the observed viral clearance delay and phagocytic dysfunction in aged olfactory mucosa were accompanied by a decline of phagocytosis-related genes. Further, robust basal stem cell activation contributed to neuroepithelial regeneration and restored ACE2 expression postinfection. Together, our study characterized the nasal tropism of SARS-CoV-2 strains, immune clearance, and regeneration after infection. The shifting characteristics of viral infection at the airway portal provide insight into the variability of COVID-19 clinical features, particularly long COVID, and may suggest differing strategies for early local intervention.

Multi-Institutional Analysis of Insurance Denial Patterns Within Rhinology.

BACKGROUND: Obtaining insurance approval is a necessary component of healthcare in the United States and denials of these claims have been estimated to result in a loss of 3% to 5% of revenue. OBJECTIVE: Examine the trends in insurance denials for rhinological procedures. METHODS: A retrospective review of deidentified financial data of patients who were treated by participating physicians across 3 institutions from January 1, 2021, to June 30, 2023. The data was queried for rhinological and non-rhinological procedures via CPT codes. Cumulative insurance denials were calculated and stratified by procedure and insurance type. Write-offs were dollar amounts associated with final denials. RESULTS: A sample of 102,984 procedures and visits revealed a final denial rate between 2.2% and 2.9% across institutions (p = .72). The top three rhinological procedures for final write-offs were: nasal endoscopy (16.24%, $111,836.87), nasal debridement or polypectomy (6.48%, $79,457.51), and destruction of intranasal lesion (2.11%, $56,932.20). The write-off percentage for each procedure was highest among commercial insurance payers as opposed to Medicare or Medicaid. CONCLUSION: Final denial rates of rhinology procedures ranged between 2% and 3%. Common procedures such as nasal endoscopy and nasal debridement are among the highest written-off procedures. Insurance denials can lead to notable revenue loss. Rhinology practices must continue to remain knowledgeable of the changes and effects of insurance reimbursement on their practice.

Postnasal drip and chronic cough in patients with chronic rhinitis treated with temperature-controlled radiofrequency neurolysis.

OBJECTIVE: To evaluate the contribution of postnasal drip (PND) and chronic cough (CC) to symptoms of patients with chronic rhinitis treated with temperature-controlled radiofrequency (TCRF) neurolysis of the posterior nasal nerve (PNN), and correlate PND and CC scores with components of the reflective total nasal symptom score (rTNSS). METHODS: Pooled data from three prospective studies: two single-arm studies and the index active treatment arm of a randomized controlled trial. Adult patients with baseline rTNSS ≥6 were treated with TCRF neurolysis at nonoverlapping regions of the PNN. PND and CC symptoms were evaluated on a 0 (none) to 3 (severe) scale. RESULTS: Data from 228 patients (57.9% women, 42.1% men) were included. The mean baseline rTNSS was 8.1 (95% confidence interval [CI], 7.8-8.3), which decreased to 3.2 (95% CI, 2.9-3.5) at 6 months. At baseline, 97.4% of patients had PND and 80.3% had CC. Median baseline PND and CC symptom scores were 3 (interquartile range [IQR], 2-3) and 2 (IQR, 1-2), respectively. At 6 months, this decreased to 1 (IQR, 0-2) and 0 (IQR, 0-1), respectively, showing significant improvement from baseline (both p < 0.001). Spearman correlation coefficients with components of rTNSS (rhinorrhea, congestion, itching, sneezing) were 0.16 to 0.22 for CC and 0.19 to 0.46 for PND, indicating only a weak to moderate correlation. CONCLUSION: PND and CC contribute to the symptomatology of chronic rhinitis and are significantly improved after TCRF neurolysis of the PNN. The inclusion of PND and CC symptoms in a chronic rhinitis assessment instrument could provide important additional information for the characterization of the disease state and outcomes after any therapeutic treatment.

Air Quality, Allergic Rhinitis, and Asthma.

This review article highlights air pollution as a critical global health concern with emphasis on its effects and role in the development and exacerbation of upper airway and lower airway disease with a focus on allergic rhinitis and asthma. This review underscores the World Health Organization's recognition of air pollution as the biggest environmental threat to human health. It discusses the various components and categories of air pollutants and the evidence-based effects they have on asthma and allergic rhinitis, ranging from pathogenesis to exacerbation of these conditions across various age groups in different geographic locations.

The incidence of asthma attributable to temperature variability: An ecological study based on 1990-2019 GBD data.

BACKGROUND: Asthma, the second leading cause of death from chronic respiratory diseases, is associated with climate change, especially temperature changes. It is currently unclear about the relationship between long-term temperature variability and the incidence of asthma on a global scale. METHODS: We used asthma incidence, demographic and socioeconomic data from the Global Burden of Disease (GBD) Results Database, and environmental and geographical statistics from TerraClimate between 1990 and 2019 to determine the association between maximum temperature variability and asthma incidence. We also predicted the incidence of heat-related asthma in the future (2020-2100) under four shared socioeconomic pathways (SSPs: 126, 245, 370, and 585). RESULTS: Between 1990 and 2019, the global median incidence of asthma was 402.0 per 100,000 with a higher incidence (median: 1380.3 per 100,000) in children under 10 years old. We found that every 1 °C increase in maximum temperature variability increased the risk of asthma globally by 5.0 %, and the effect was robust for individuals living in high-latitude areas or aged from 50 to 70 years. By 2100, the average incidence of asthma is estimated to be reduced by 95.55 %, 79.32 %, and 40.02 % under the SSP126, SSP245, and SSP370 scenarios, respectively, compared to the SSP585 at latitudes >60°. CONCLUSION: Our study provides evidence that maximum temperature variability is associated with asthma incidence. These findings suggest that implementing stricter mitigation and adaptation strategies may be importment in reducing asthma cases caused by climate change.

SARS-CoV-2 infection alters mitochondrial and cytoskeletal function in human respiratory epithelial cells mediated by expression of spike protein.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, SCV2), which has resulted in higher morbidity and mortality rate than other respiratory viral infections, such as Influenza A virus (IAV) infection. Investigating the molecular mechanisms of SCV2-host infection vs IAV is vital in exploring antiviral drug targets against SCV2. We assessed differential gene expression in human nasal cells upon SCV2 or IAV infection using RNA sequencing. Compared to IAV, we observed alterations in both metabolic and cytoskeletal pathways suggestive of epithelial remodeling in the SCV2-infected cells, reminiscent of pathways activated as a response to chronic injury. We found that spike protein interaction with the epithelium was sufficient to instigate these epithelial responses using a SCV2 spike pseudovirus. Specifically, we found downregulation of the mitochondrial markers SIRT3 and TOMM22. Moreover, SCV2 spike infection increased extracellular acidification and decreased oxygen consumption rate in the epithelium. In addition, we observed cytoskeletal rearrangements with a reduction in the actin-severing protein cofilin-1 and an increase in polymerized actin, indicating epithelial cytoskeletal rearrangements. This study revealed distinct epithelial responses to SCV2 infection, with early mitochondrial dysfunction in the host cells and evidence of cytoskeletal remodeling that could contribute to the worsened outcome in COVID-19 patients compared to IAV patients. These changes in cell structure and energetics could contribute to cellular resilience early during infection, allowing for prolonged cell survival and potentially paving the way for more chronic symptoms. IMPORTANCE COVID-19 has caused a global pandemic affecting millions of people worldwide, resulting in a higher mortality rate and concerns of more persistent symptoms compared to influenza A. To study this, we compare lung epithelial responses to both viruses. Interestingly, we found that in response to SARS-CoV-2 infection, the cellular energetics changed and there were cell structural rearrangements. These changes in cell structure could lead to prolonged epithelial cell survival, even in the face of not working well, potentially contributing to the development of chronic symptoms. In summary, these findings represent strategies utilized by the cell to survive the infection but result in a fundamental shift in the epithelial phenotype, with potential long-term consequences, which could set the stage for the development of chronic lung disease or long COVID-19.

International Multicenter Study of Clinical Outcomes of Sinonasal Melanoma Shows Survival Benefit for Patients Treated with Immune Checkpoint Inhibitors and Potential Improvements to the Current TNM Staging System.

Objectives Sinonasal mucosal melanoma (SNMM) is an extremely rare and challenging sinonasal malignancy with a poor prognosis. Standard treatment involves complete surgical resection, but the role of adjuvant therapy remains unclear. Crucially, our understanding of its clinical presentation, course, and optimal treatment remains limited, and few advancements in improving its management have been made in the recent past. Methods We conducted an international multicenter retrospective analysis of 505 SNMM cases from 11 institutions across the United States, United Kingdom, Ireland, and continental Europe. Data on clinical presentation, diagnosis, treatment, and clinical outcomes were assessed. Results One-, three-, and five-year recurrence-free and overall survival were 61.4, 30.6, and 22.0%, and 77.6, 49.2, and 38.3%, respectively. Compared with disease confined to the nasal cavity, sinus involvement confers significantly worse survival; based on this, further stratifying the T3 stage was highly prognostic ( p < 0.001) with implications for a potential modification to the current TNM staging system. There was a statistically significant survival benefit for patients who received adjuvant radiotherapy, compared with those who underwent surgery alone (hazard ratio [HR] = 0.74, 95% confidence interval [CI]: 0.57-0.96, p = 0.021). Immune checkpoint blockade for the management of recurrent or persistent disease, with or without distant metastasis, conferred longer survival (HR = 0.50, 95% CI: 0.25-1.00, p = 0.036). Conclusions We present findings from the largest cohort of SNMM reported to date. We demonstrate the potential utility of further stratifying the T3 stage by sinus involvement and present promising data on the benefit of immune checkpoint inhibitors for recurrent, persistent, or metastatic disease with implications for future clinical trials in this field.

Association between ambient temperature and chronic rhinosinusitis.

BACKGROUND: Chronic exposure to particulate matter air pollution (PM2.5 ) is associated with chronic rhinosinusitis (CRS). Elevated ambient temperature may increase PM2.5 levels and thereby exacerbate sinonasal symptoms. This study investigates the association between high ambient temperature and the risk of CRS diagnosis. METHODS: Patients with CRS were diagnosed at Johns Hopkins hospitals from May to October 2013-2022, and controls were matched patients without CRS meanwhile. A total of 4752 patients (2376 cases and 2376 controls) were identified with a mean (SD) age of 51.8 (16.8) years. The effect of maximum ambient temperature on symptoms was estimated with a distributed lag nonlinear model (DLNM). Extreme heat was defined as 35.0°C (95th percentile of the maximum temperature distribution). Conditional logistic regression models estimated the association between extreme heat and the risk of CRS diagnosis. RESULTS: Exposure to extreme heat was associated with increased odds of exacerbation of CRS symptoms (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.03-1.19). The cumulative effect of extreme heat during 0-21 lag days was significant (OR 2.37, 95% CI 1.60-3.50) compared with the minimum morbidity temperature (MMT) at 25.3°C. Associations were more pronounced among young and middle-aged patients and patients with abnormal weight. CONCLUSIONS: We found that short-term exposure to high ambient temperature is associated with increased CRS diagnosis, suggesting a cascading effect of meteorological phenomena. These results highlight climate change's potentially deleterious health effects on upper airway diseases, which could have a significant public health impact.

Scientific Advancements That Empower Us to Understand CRS Pathophysiology.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a multifactorial inflammatory condition that remains poorly understood. Over the past decade, we have witnessed impressive scientific advancements that have allowed us to better understand the molecular and cellular mechanisms that underlie the inflammatory processes in mucosal diseases including asthma, allergic rhinitis, and CRSwNP. OBJECTIVE: The present review aims to summarize and highlight the most recent scientific advancements that have enriched our understanding of CRSwNP. METHODS: A comprehensive review of the available literature on the use of new scientific techniques in CRSwNP was performed. We evaluated the most recent evidence from studies using animal models, cell cultures, and genome sequencing techniques and their impact on our understanding of CRSwNP pathophysiology. RESULTS: Our understanding of CRSwNP has rapidly progressed with the development of newer scientific techniques to interrogate various pathways involved in its pathogenesis. Animal models remain powerful tools and have elucidated the mechanisms behind esinophilic inflammation in CRSwNP; however, animal models reproducing polyp formation are relatively sparse. 3D cell cultures have significant potential to better dissect the cellular interactions with the sinonasal epithelium and other cell types in CRS. Additionally, some groups are starting to utilize single-cell RNA sequencing to investigate RNA expression in individual cells with high resolution and on a genomic scale. CONCLUSION: These emerging scientific technologies represent outstanding opportunities to identify and develop more targeted therapeutics for different pathways that lead to CRSwNP. An additional understanding of these mechanisms will be critical for developing future therapies for CRSwNP.

Socioeconomic disparity in the association between fine particulate matter exposure and papillary thyroid cancer.

BACKGROUND: Limited data exists suggesting that cumulative exposure to air pollution in the form of fine particulate matter (aerodynamic diameter ≤ 2.5 µm [PM2.5]) may be associated with papillary thyroid carcinoma (PTC), although this relationship has not been widely established. This study aims to evaluate the association between PM2.5 and PTC and determine the subgroups of patients who are at the highest risk of PTC diagnosis. METHODS: Under IRB approval, we conducted a case-control study of adult patients (age ≥ 18) newly diagnosed with PTC between 1/2013-12/2016 across a single health care system were identified using electronic medical records. These patients were compared to a control group of patients without any evidence of thyroid disease. Cumulative PM2.5 exposure was calculated for each patient using a deep learning neural networks model, which incorporated meteorological and satellite-based measurements at the patients' residential zip code. Adjusted multivariate logistic regression was used to quantify the association between cumulative PM2.5 exposure and PTC diagnosis. We tested whether this association differed by gender, race, BMI, smoking history, current alcohol use, and median household income. RESULTS: A cohort of 1990 patients with PTC and a control group of 6919 patients without thyroid disease were identified. Compared to the control group, patients with PTC were more likely to be older (51.2 vs. 48.8 years), female (75.5% vs 46.8%), White (75.2% vs. 61.6%), and never smokers (71.1% vs. 58.4%) (p < 0.001). After adjusting for age, sex, race, BMI, current alcohol use, median household income, current smoking status, hypertension, diabetes, COPD, and asthma, 3-year cumulative PM2.5 exposure was associated with a 1.41-fold increased odds of PTC diagnosis (95%CI: 1.23-1.62). This association varied by median household income (p-interaction =0.03). Compared to those with a median annual household income <$50,000, patients with a median annual household income between $50,000 and < $100,000 had a 43% increased risk of PTC diagnosis (aOR = 1.43, 95%CI: 1.19-1.72), and patients with median household income ≥$100,000 had a 77% increased risk of PTC diagnosis (aOR = 1.77, 95%CI: 1.37-2.29). CONCLUSIONS: Cumulative exposure to PM2.5 over 3 years was significantly associated with the diagnosis of PTC. This association was most pronounced in those with a high median household income, suggesting a difference in access to care among socioeconomic groups.

Association between temperature variability and global meningitis incidence.

BACKGROUND: Meningitis can cause devastating epidemics and is susceptible to climate change. It is unclear how temperature variability, an indicator of climate change, is associated with meningitis incidence. METHODS: We used global meningitis incidence data along with meteorological and demographic data over 1990-2019 to identify the association between temperature variability and meningitis. We also employed future (2020-2100) climate data to predict meningitis incidence under different emission levels (SSPs: Shared Socioeconomic Pathways). RESULTS: We found that the mean temperature variability increased by almost 3 folds in the past 30 years. The largest changes occurred in Australasia, Tropical Latin America, and Central Sub-Saharan Africa. With a logarithmic unit increase in temperature variability, the overall global meningitis risk increases by 4.8 %. Australasia, Central Sub-Saharan Africa, and High-income North America are the most at-risk regions. Higher statistical differences were identified in males, children, and the elderly population. Compared to high-emission (SSP585) scenario, we predicted a median reduction of 85.8 % in meningitis incidence globally under the low-emission (SSP126) climate change scenario by 2100. CONCLUSION: Our study provides evidence for temperature variability being in association with meningitis incidence, which suggests that global actions are urgently needed to address climate change and to prevent meningitis occurrence.

Climate change, the environment, and rhinologic disease.

BACKGROUND: The escalating negative impact of climate change on our environment has the potential to result in significant morbidity of rhinologic diseases. METHODS: Evidence based review of examples of rhinologic diseases including allergic and nonallergic rhinitis, chronic rhinosinusitis, and allergic fungal rhinosinusitis was performed. RESULTS: The lower socioeconomic population, including historically oppressed groups, will be disproportionately affected. CONCLUSIONS: We need a systematic approach to improve healthcare database infrastructure and funding to promote diverse scientific collaboration to address these healthcare needs.

Unified Airway Disease: Environmental Factors.

The unified airway is in constant exposure to environmental factors that promote inflammation and disease. Environmental allergens, including house dust mites, pets, pollens, and molds, are strongly linked with development and exacerbation of upper airway disease with nonlinear dose-dependent relationships. Occupational triggers, including combat exposures and construction workers, are associated with the development of both upper and lower airway disease resulting in a "healthy worker effect" where many people leave jobs due to significant morbidity..

Patient reported outcomes and treatment satisfaction in patients with cushing syndrome.

PURPOSE: Cushing Syndrome (CS) is a rare endocrine disorder associated with physical and mental symptoms that can drastically affect quality of life (QoL). This study characterizes QoL in patients with CS, describes their treatment experiences, and identifies patient subsets associated with decreased QoL or shared impressions of treatment. METHODS: A 136-question survey addressing QoL factors and treatment experiences was completed by adult patients with CS from the Cushing Support and Research Foundation. Patient demographics, tumor characteristics, and treatment information were collected. Bivariate analyses were conducted to determine if patients' symptoms or treatment experiences were significantly associated with demographics or other variables. RESULTS: A total of 178 patients, predominantly female (94%) with mean age 53 years, completed the survey. Anxiety and/or depression (n = 163, 94%), loss of physical strength (n = 164, 93%), loneliness (n = 156, 90%), fatigue from treatment (n = 142, 89%), memory loss (n = 153, 88%), insomnia (n = 144, 83%), and pain (n = 141, 83%) were symptoms most commonly experienced by respondents. Patients experiencing delay of diagnosis >10 years were more likely to have suicidal thoughts (p = 0.002). Younger patients were more likely to express concerns about hair loss (p = 0.007), loneliness (p = 0.025), pain (p = 0.004), or the impact of CS on their marriage (p = 0.039) or children (p = 0.024). CONCLUSION: This survey demonstrates CS impacts patients across many dimensions, emphasizing the need for holistic support. We identified patient subsets in which QoL may be improved with additional patient resources or provider attention.

Etiology of sinonasal inverted papilloma: An update.

Objective: Sinonasal inverted papilloma (IP) and its clinical features have been widely studied, but there are few studies delving into its etiology and risk factors. A narrative review was conducted to summarize a contemporary understanding of the potential etiologies of IP, including immunologic/inflammatory, viral, genetic, and environmental causes. Study Design: Review. Methods: A MEDLINE search was conducted through August 11, 2021, focusing on studies investigating the etiology and risk factors for sinonasal IP and its malignant transformation. Results: High- and low-risk human papillomavirus have been connected with the formation of IP, but conflicting evidence exists regarding their role. Occupational and industrial exposures may also contribute to IP formation, while smoking may increase the odds of malignant progression. Exon 20 mutations in EGFR are an active area of research in IP with mixed evidence. Finally, several cell cycle and angiogenic factors such as Ki67, VEGF, and Akt/mTOR have been implicated in the development and progression of IP. Conclusion: There continues to be conflicting evidence around the development of IP, but significant progress has been made in recent years. Further study is needed for all these potential etiologies to elucidate risk factors and therapeutic strategies.

The Association Between E-Cigarette Use and Prediabetes: Results From the Behavioral Risk Factor Surveillance System, 2016-2018.

INTRODUCTION: Both E-cigarette use and the prevalence of prediabetes have risen dramatically in the past decade. It is crucial to understand whether E-cigarette use is associated with the risk of prediabetes. METHODS: Participants who completed the prediabetes and E-cigarette modules of the Behavioral Risk Factor Surveillance System survey (2016-2018) were included in this study. E-cigarette use information was collected by asking: Have you ever used an e-cigarette or other electronic "vaping" product, even just one time, in your entire life? We defined sole E-cigarette users as current E-cigarette users who are never combustible-cigarette users, and dual users were defined as both current E-cigarette and combustible-cigarette users. Participants with prediabetes were identified by asking: Ever been told by a doctor or other health professional that you have prediabetes or borderline diabetes? Multivariable logistic regression was used to determine the association between E-cigarette use and prediabetes. RESULTS: Among the 600,046 respondents, 28.6% of respondents were aged <35 years. The prevalence of prediabetes among current E-cigarette, sole E-cigarette users, and dual users was 9.0% (95% CI=8.6, 9.4), 5.9% (95% CI=5.3, 6.5), and 10.2% (95% CI=9.8, 10.7), respectively. In the fully adjusted model, the ORs for prediabetes were 1.22 (95% CI=1.10, 1.37) for current E-cigarette users and 1.12 (95% CI=1.05, 1.19) for former E-cigarette users compared with that of never E-cigarette users. The ORs for prediabetes were 1.54 (95% CI=1.17, 2.04) for sole E-cigarette users and 1.14 (95% CI=0.97, 1.34) for dual users. CONCLUSIONS: In this representative sample of U.S. adults, E-cigarette use was associated with greater odds of prediabetes. The results were consistent in sole E-cigarette users.

Environmental air pollution and chronic rhinosinusitis: A systematic review.

Objective: Chronic rhinosinusitis (CRS) is a highly prevalent and burdensome disease. The pathophysiology is not fully elucidated, but environmental pollutants have been suggested to impact the inflammatory component of the disease process. This review aims to summarize the role of environmental pollution in CRS onset and disease severity. Methods: A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were queried in August 2021. Original articles reporting on air pollution exposure in CRS were included. Other forms of sinonasal disease were excluded. Results: Literature search produced 11,983 articles, of which 10 met inclusion criteria. Outcomes evaluated included incidence/prevalence, disease severity, quality of life, and histopathologic/microbial changes. Air pollutant exposure was associated with higher odds of CRS, particularly with particulate matter (PM) exposure. Increasing air pollution exposure was also associated with worsened disease severity and detectable histopathologic changes. Impact on quality of life was less clear. Conclusion: Air pollution (particularly PM) is correlated with CRS incidence/prevalence and disease severity, with evidence of histopathologic changes in CRS tissue samples. Further research is warranted to better understand the mechanisms by which air pollution components may cause CRS and type 2 inflammation. Level of Evidence: 3a.