Air pollution associated with incidence and progression trajectory of chronic lung diseases: a population-based cohort study

The impact of place on multimorbidity: A systematic scoping review

Multimorbidity, commonly defined as the co-existence of two or more long-term conditions, is a major global public health challenge with significant impacts for health and social care systems. There is a substantial body of work identifying different individual- and household-level determinants of multimorbidity, yet the role of place-based characteristics in affecting multimorbidity remains limited. This systematic scoping review identifies place-based risk factors for multimorbidity and further synthesises the potential pathways explaining these relationships using longitudinal evidence. By systematically searching seven major databases, such as Medline, Embase, and Web of Science, using relevant search terms (e.g., MeSH) relating to place-based risk factors and multimorbidity, 76 out of 7761 studies were included for evidence synthesis. We include studies exploring the relationship between place-based risk factors and multimorbidity among the general population older than 18 years old in the setting of community-dwelling, primary, and secondary care. We identified 12 types of place-based risk factors, with the impacts of area-level deprivation/SES, pollution, and urban/rurality on multimorbidity being most frequently considered and with the most consistent findings, with people living in more deprived/low SES, highly polluted, or more urbanised areas having increased risks of multimorbidity. Further, the impact of these place-based risk factors on multimorbidity varied according to the operationalisation of the multimorbidity measure. We also identified that the impacts of other types of place-based factors on multimorbidity remain underexplored, such as social cohesion and greenspace. Finally, using these longitudinal findings, we propose a conceptual framework linking place and multimorbidity. We suggest that future studies explore a wider range of place-level environmental exposures and use more precise measures, exploit electronic health records to implement more consistent and reproducible measurements of multimorbidity, moreover, make greater use of longitudinal study designs or analytical approaches better suited to identifying causal processes.

Air Pollution Metabolomic Signatures and Chronic Respiratory Diseases Risk: A Longitudinal Study

BACKGROUND

Although evidence has documented the associations of ambient air pollution with chronic respiratory diseases (CRDs) and lung function, the underlying metabolic mechanisms remain largely unclear.

RESEARCH QUESTION

How does the metabolomic signature for air pollution relate to CRD risk, respiratory symptoms, and lung function?

STUDY DESIGN AND METHODS

We retrieved 171,132 participants free of COPD and asthma at baseline from the UK Biobank, who had data on air pollution and metabolomics. Exposures to air pollutants (particulate matter with diameter ≤ 2.5 μm [PM2.5], particulate matter with a diameter ≤ 10 μm, nitrogen oxide [NOX], and NO2) were assessed for 4 years before baseline considering residential address histories. We used 10-fold cross-validation elastic net regression to identify air pollution-associated metabolites. Multivariable Cox models were used to assess the associations between metabolomic signatures and CRD risk. Mediation and pathway analysis were conducted to explore the metabolic mechanism underlying the associations.

RESULTS

During a median follow-up of 12.51 years, 8,951 and 5,980 incident COPD and asthma cases were recorded. In multivariable Cox regressions, air pollution was positively associated with CRD risk (eg, hazard ratio per interquartile range increment in PM2.5, 1.09; 95% CI, 1.06-1.13). We identified 103, 86, 85, and 90 metabolites in response to PM2.5, particulate matter with a diameter ≤ 10 μm, NOX, and NO2 exposure, respectively. The metabolomic signatures showed significant associations with CRD risk (hazard ratio per SD increment in PM2.5 metabolomic signature, 1.11; 95% CI, 1.09-1.14). Mediation analysis showed that peripheral inflammatory and erythrocyte-related markers mediated the effects of metabolomic signatures on CRD risk. We identified 14 and 12 perturbed metabolic pathways (energy metabolism and amino acid metabolism pathways, etc) for PM2.5 and NOX metabolomic signatures.

INTERPRETATION

Our study identifies metabolomic signatures for air pollution exposure. The metabolomic signatures showed significant associations with CRD risk, and inflammatory- and erythrocyte-related markers partly mediated the metabolomic signatures-CRD links.

Long-Term Exposure to Nitrogen Dioxide and Ozone and Mortality: Update of the WHO Air Quality Guidelines Systematic Review and Meta-Analysis

Objectives

We performed a systematic review and meta-analysis on long-term exposure to nitrogen dioxide (NO2) and ozone (O3) with mortality, to expand evidence that informed 2021 the WHO Air Quality Guidelines and guide the Health Risks of Air Pollution in Europe project.

Methods

We included cohorts investigating NO2 and O3 mortality from all-causes, respiratory diseases, chronic obstructive pulmonary disease (COPD), acute lower respiratory infections (ALRI); and NO2 mortality from circulatory, ischemic heart, cerebrovascular diseases and lung cancer. We pooled estimates by random-effects models and investigated heterogeneity. We assessed the certainty of the evidence using the Grading of Recommendations Assessment Development approach and Evaluation (GRADE).

Results

We selected 83 studies for NO2 and 26 for O3 for the meta-analysis. NO2 was associated with all outcomes, except for cerebrovascular mortality. O3 was associated with respiratory mortality following annual exposure. There was high heterogeneity, partly explained by region and pollutant levels. Certainty was high for NO2 with COPD and ALRI, and annual O3 with respiratory mortality.

Conclusion

An increasing body of evidence, with new results from countrywide areas and the Western Pacific, supports certainty, including new outcomes.

Individual and joint exposure to air pollutants and patterns of multiple chronic conditions

Existing research on the detrimental effects of air pollution and its mixture on multiple chronic conditions (MCC) is not yet fully recognized. Our objective was to examine if individual and joint exposure to air pollution is associated with the incidence and patterns of MCC. Totally 10,231 CHARLS 2015 participants aged over 45 years and 1,938 without MCC were followed up in 2018 and 2020. Residential-levelcumulative personal exposure concentrations of PM1, PM10, PM2.5, CO, O3, NO2, SO2, NO3-, Cl-, NH4+, and SO42- at the residential level were determined utilizing a spatio-temporal random forest model with a spatial resolution of 0.1° × 0.1°. In the cross-sectional and longitudinal research, logistic regression, cox regression analysis, and quantile g-computation were utilized to estimate the single and joint effect with MCC and its patterns, respectively. Interaction analyses and stratified analyses were also performed. A correlation was observed between the prevalence of cardiovascular illnesses and the presence of all 11 major air pollutants. PM2.5, PM10, NH4+, NO3-, CO, and SO42- are associated with an increased frequency of respiratory disorders. An increase of PM2.5, PM1, PM10, NO2, and SO2 (a 10 µg/m3 rise), CO (a 0.1 mg/m3 rise), and PMCs (Cl-, NH4+, NO3-, and SO42-) (a 1 µg/m3 rise) corresponded to the HRs (95% CI) for developing MCC of 1.194 (95% CI: 1.043, 1.367), 1.362 (95% CI: 1.073, 1.728), 1.115 (95% CI: 1.026, 1.212), 1.443 (95% CI: 1.151, 1.808), 3.175 (95% CI: 2.291, 4.401), 1.272 (95% CI: 1.149,1.410), 1.382 (95% CI: 1.011, 1.888), 1.107 (95% CI: 1.003, 1.222), 1.035 (95% CI: 0.984, 1.088), and 1.122 (95% CI: 1.086, 1.160), respectively. SO2 was the predominant contributor to the combined effect (HR: 2.083, 95% CI: 1.659-2.508). Gender, age, drinking, and health status could modify the effects of air pollutants on MCC patterns. Long-term exposure to air pollution is correlated to the incidence and patterns of MCC in middle-aged and elderly Chinese individuals. Preventive methods are essential to safeguarding those susceptible to MCC.

The effect of air pollutants on COPD-hospitalized patients in Lanzhou, China (2015-2019)

Background

Lanzhou is the largest heavy industrial city in northwest China and it is a typical geographical valley-like city. However, there are few studies on the relationship between air pollutants and COPD, and their respective sample sizes are small, resulting in inconsistent results. The aim of this study is to analyze the effects of air pollutants on COPD hospitalizations in Lanzhou, China.

Methods

An ecological time series study with distributed lag non-linear model (DLNM) was used for analysis. Daily COPD hospitalization data in Lanzhou from 1 January 2015 to 31 December 2019 were collected from 25 hospitals, as well as air pollutant data and meteorological data.

Results

A total of 18,275 COPD hospitalizations were enrolled. For 10 μg/m3 increase in PM2.5, PM10, SO2, NO2, and 1 mg/m3 increase in CO at lag 07 day, the RR95%CI of COPD hospitalizations were 1.048 (1.030, 1.067), 1.008 (1.004, 1.013), 1.091 (1.048, 1.135), 1.043 (1.018, 1.068), and 1.160 (1.084, 1.242), respectively. The exposure-response curves between air pollutants (except O3-8h) and COPD hospitalizations were approximately linear with no thresholds. Female, and the harmful effect of PM on aged <65 years, the effect of gaseous pollutant on those aged ≥65 years, were stronger, particularly in the cold season. Exposure to air pollutants (except O3-8h) might increase the risk of COPD hospitalizations. O3-8h has a weak and unstable effect on COPD.

Conclusion

Exposure to air pollutants (except O3-8h) increases the risk of COPD hospitalizations. O3-8h has a weak and unstable effect on COPD hospital admissions. The harmful effect of gaseous pollutants (except O3-8h) on COPD-hospitalized patients was stronger than that of PM.

Asthma Inception: Epidemiologic Risk Factors and Natural History Across the Life Course

Asthma is a descriptive label for an obstructive inflammatory disease in the lower airways manifesting with symptoms including breathlessness, cough, difficulty in breathing, and wheezing. From a clinician's point of view, asthma symptoms can commence at any age, although most patients with asthma-regardless of their age of onset-seem to have had some form of airway problems during childhood. Asthma inception and related pathophysiologic processes are therefore very likely to occur early in life, further evidenced by recent lung physiologic and mechanistic research. Herein, we present state-of-the-art updates on the role of genetics and epigenetics, early viral and bacterial infections, immune response, and pathophysiology, as well as lifestyle and environmental exposures, in asthma across the life course. We conclude that early environmental insults in genetically vulnerable individuals inducing abnormal, pre-asthmatic airway responses are key events in asthma inception, and we highlight disease heterogeneity across ages and the potential shortsightedness of treating all patients with asthma using the same treatments. Although there are no interventions that, at present, can modify long-term outcomes, a precision-medicine approach should be implemented to optimize treatment and tailor follow-up for all patients with asthma.

Mitochondrial dysfunction-associated alveolar epithelial senescence is involved in CdCl2-induced COPD-like lung injury

An earlier study found that respiratory cadmium chloride (CdCl2) exposure caused COPD-like lung injury. This study aimed to explore whether mitochondrial dysfunction-mediated alveolar epithelial senescence is involved in CdCl2-induced COPD-like lung injury. Adult C57BL/6 mice were exposed to CdCl2 (10 mg/L) aerosol for six months. Beta-galactosidase-positive cells, p21 and p16 were increased in CdCl2-exposed mouse lungs. The in vitro experiments showed that γ-H2AX was elevated in CdCl2-exposed alveolar epithelial cells. The cGAS-STING pathway was activated in CdCl2-exposed alveolar epithelial cells and mouse lungs. Cxcl1, Cxcl9, Il-10, Il-1β and Mmp2, several senescence-associated secretory phenotypes (SASP), were upregulated in CdCl2-exposed alveolar epithelial cells. Mechanistically, CdCl2 exposure caused SIRT3 reduction and mitochondrial dysfunction in mouse lungs and alveolar epithelial cells. The in vitro experiment found that Sirt3 overexpression attenuated CdCl2-induced alveolar epithelial senescence and SASP. The in vivo experiments showed that Sirt3 gene knockout exacerbated CdCl2-induced alveolar epithelial senescence, alveolar structure damage, airway inflammation and pulmonary function decline. NMN, an NAD+ precursor, attenuated CdCl2-induced alveolar epithelial senescence and SASP in mouse lungs. Moreover, NMN supplementation prevented CdCl2-induced COPD-like alveolar structure damage, epithelial-mesenchymal transition and pulmonary function decline. These results suggest that mitochondrial dysfunction-associated alveolar epithelial senescence is involved in CdCl2-induced COPD-like lung injury.

Long-term exposure to ambient ozone and adult-onset asthma: A prospective cohort study

BACKGROUND

The association between long-term exposure to ozone (O3) and adult-onset asthma (AOA) remains inconclusive, and analysis of causality is lacking.

OBJECTIVES

To examine the causal association between long-term O3 exposure and AOA.

METHODS

A prospective cohort study of 362,098 participants was conducted using the UK Biobank study. Incident cases of AOA were identified using health administrative data of the National Health Services. O3 exposure at participants' residential addresses was estimated by a spatio-temporal model. Instrumental variable (IV) modelling was used to analyze the causal association between O3 exposure and AOA, by incorporating wind speed and planetary boundary layer height as IVs into time-dependent Cox model. Negative control outcome (accidental injury) was also used to additionally evaluate unmeasured confounding.

RESULTS

During a mean follow-up of 11.38 years, a total of 10,973 incident AOA cases were identified. A U-shaped concentration-response relationship was observed between O3 exposure and AOA in the traditional Cox models with HR of 0.916 (95% CI: 0.888, 0.945) for O3 at low levels (<38.17 ppb), and 1.204 (95% CI: 1.168, 1.242) for O3 at high levels (≥38.17 ppb). However, in the IV analysis we only found a statistically significant association between high-level O3 exposure and AOA risk, but not for low-level O3 exposure. No significant associations between O3 exposure and accidental injury were observed.

CONCLUSION

Our findings suggest a potential causal relationship between long-term exposure to high-level ambient O3 and increased risks of AOA.

Inflammatory Status in Trained and Untrained Mice at Different Pollution Levels

Atmospheric pollution can be defined as a set of changes that occur in the composition of the air, making it unsuitable and/or harmful and thereby generating adverse effects on human health. The regular practice of physical exercise (PE) is associated with the preservation and/or improvement of health; however, it can be influenced by neuroimmunoendocrine mechanisms and external factors such as air pollution, highlighting the need for studies involving the practice of PE in polluted environments. Herein, 24 male C57BL/6 mice were evaluated, distributed into four groups (exposed to a high concentration of pollutants/sedentary, exposed to a high concentration of pollutants/exercised, exposed to ambient air/sedentary, and exposed to ambient air/exercised). The exposure to pollutants occurred in the environmental particle concentrator (CPA) and the physical training was performed on a treadmill specially designed for use within the CPA. Pro- and anti-inflammatory markers in blood and bronchoalveolar lavage (BALF), BALF cellularity, and lung tissue were evaluated. Although the active group exposed to a high concentration of pollution showed a greater inflammatory response, both the correlation analysis and the ratio between pro- and anti-inflammatory cytokines demonstrated that the exercised group presented greater anti-inflammatory activity, suggesting a protective/adaptative effect of exercise when carried out in a polluted environment.

Association between threat-related adverse childhood experiences and chronic lung diseases in a middle and older aged population: A cross-sectional and longitudinal study in China

OBJECTIVES

We investigated the association between threat-related adverse childhood experiences (ACEs) and the risk of chronic lung diseases (CLDs).

METHODS

The data used for this study were extracted from the China Health and Retirement Longitudinal Study (CHARLS), a nationally representative survey of respondents recruited from 450 villages/urban communities in 28 provinces. Threat-related ACEs were constructed using five adverse factors: household substance abuse, physical abuse, domestic violence, unsafe neighbourhood, and bullying). Participants were divided into three groups according to their number of threat-related ACEs at baseline and at follow-up. The association between threat-related ACEs and CLD prevalence in the cross-sectional study was calculated using logistic regression models. The association between threat-related ACEs and CLD onset was evaluated using Cox proportional regression models in the cohort study. Potential confounders were considered in both the cross-sectional and cohort studies.

RESULTS

The CLD prevalence in the total population, no exposure group, exposure to one threat-related ACE, and exposure to at least two threat-related ACEs were 10.07% (1320/13104), 9.20% (665/7232), 10.89% (421/3865), and 11.66% (234/2007), respectively. Exposure to one threat-related ACE (OR: 1.23, 95% CI: 1.07-1.41) and exposure to at least two threat-related ACEs (OR: 1.31, 95% CI: 1.11-1.55) were significantly associated with higher CLD prevalence rates. The cohort study included 11,645 participants. During the 7-year follow-up, 738 CLD incidents were identified. Similarly, exposure to one threat-related ACE (HR: 1.20, 95% CI: 1.01-1.43) and at least two threat-related ACEs (HR: 1.64, 95% CI: 1.35-2.00) were significantly associated with a higher CLD incidence risk.

CONCLUSIONS

Exposure to threat-related ACEs was significantly associated with a higher CLD prevalence risk and onset. It is crucial to identify individuals who have encountered childhood threats and prioritise the monitoring of their pulmonary function.

Association between ambient air pollutants and short-term mortality risks during 2015-2019 in Guangzhou, China

With the development of technology and industry, the problem of global air pollution has become difficult to ignore. We investigated the association between air pollutant concentrations and daily all-cause mortality and stratified the analysis by sex, age, and season. Data for six air pollutants [fine particulate matter (PM2.5), inhalable particles (PM10), nitric dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO)] and daily mortality rates were collected from 2015 to 2019 in Guangzhou, China. A time-series study using a quasi-Poisson generalized additive model was used to examine the relationships between environmental pollutant concentrations and mortality. Mortality data for 296,939 individuals were included in the analysis. The results showed that an increase of 10 μg/m3 in the concentrations of PM2.5, PM10, SO2, O3, NO2, and CO corresponded to 0.84% [95% confidence interval (CI): 0.47, 1.21%], 0.70% (0.44, 0.96%), 3.59% (1.77, 5.43%), 0.21% (0.05, 0.36%), 1.06% (0.70, 1.41%), and 0.05% (0.02, 0.09%), respectively. The effects of the six air pollutants were more significant for male individuals than female individuals, the cool season than the warm season, and people 75 years or older than those younger than 75 years. PM2.5, PM10, SO2, and NO2 were all associated with neoplasms and circulatory and respiratory diseases. The two-pollutant models found that PM2.5, PM10, and NO2 may independently affect the risk of mortality. The results showed that exposure to PM2.5, PM10 and NO2 may increase the risk of daily all-cause excessive mortality in Guangzhou.

Myeloid Heterogeneity Mediates Acute Exacerbations of Pulmonary Fibrosis

Epidemiological evidence indicates that exposure to particulate matter is linked to the development of idiopathic pulmonary fibrosis (IPF) and increases the incidence of acute exacerbations of IPF. In addition to accelerating the rate of lung function decline, exposure to fine particulate matter (particulate matter smaller than 2.5 μm [PM2.5]) is a risk factor for increased mortality in subjects with IPF. In this article, we show that exposure to PM2.5 mediates monocyte recruitment and fibrotic progression in mice with established fibrosis. In mice with established fibrosis, bronchoalveolar lavage cells showed monocyte/macrophage heterogeneity after exposure to PM2.5. These cells had a significant inflammatory and anti-inflammatory signature. The mixed heterogeneity of cells contributed to the proinflammatory and anti-inflammatory response. Although monocyte-derived macrophages were recruited to the lung in bleomycin-injured mice treated with PM2.5, recruitment of monocytes expressing Ly6Chi to the lung promoted progression of fibrosis, reduced lung aeration on computed tomography, and impacted lung compliance. Ly6Chi monocytes isolated from PM2.5-exposed fibrotic mice showed enhanced expression of proinflammatory markers compared with fibrotic mice exposed to vehicle. Moreover, IPF bronchoalveolar lavage cells treated ex vivo with PM2.5 showed an exaggerated inflammatory response. Targeting Ly6Chi monocyte recruitment inhibited fibrotic progression in mice. Moreover, the adoptive transfer of Ly6Chi monocytes exacerbated established fibrosis. These observations suggest that enhanced recruitment of Ly6Chi monocytes with a proinflammatory phenotype mediates acute exacerbations of pulmonary fibrosis, and targeting these cells may provide a potential novel therapeutic target to protect against acute exacerbations of IPF.

Short-Term Ambient Air Pollution and Urticaria in Guangzhou, China: Estimating the Association and Population Attributable Fraction

Limited evidence is available regarding the association between acute exposure to ambient air pollutants and the risk of urticaria, even though the skin is an organ with direct contact with the external environment. This study utilized generalized additive models to investigate the association between particulate matter with an aerodynamic diameter smaller than 10 μm (PM10) and 2.5 μm (PM2.5), nitrogen dioxide (NO2) and sulfur dioxide (SO2), and daily outpatient visits for urticaria in Guangzhou, China from 2013 to 2017. We also estimated the attributable fraction of urticaria outpatient visits due to air pollution. A total of 216,648 outpatient visits due to urticaria occurred during the study period. All air pollutants were significantly associated with an increased excess risk of urticaria. Each 10 μg/m3 increase in PM2.5, PM10, NO2, and SO2 was associated with an increase of 1.23% (95% CI: 0.42%, 2.06%), 0.88% (95% CI: 0.28%, 1.49%), 3.09% (95% CI: 2.16%, 4.03%), and 2.82% (95% CI: 0.93%, 4.74%) in hospital visits for urticaria at lag05, respectively. It was estimated that 3.77% (95% CI: 1.26%, 6.38%), 1.91% (95% CI: 0.60%, 3.26%), 6.36% (95% CI: 4.38%, 8.41%), and 0.08% (95% CI: 0.03%, 0.14%) of urticaria outpatient visits were attributable to PM2.5, PM10, NO2, and SO2 using the World Health Organization's air quality guideline as the reference. Relatively stronger associations were observed during the cold season. This study indicates that short-term air pollution may play a significant role in outpatient visits for urticaria, and that such relationships could be modified by season.

Ambient air pollution associated with incident asthma, subsequent cardiovascular disease and death: A trajectory analysis of a national cohort

No previous study has examined the impact of air pollution on the cardiovascular disease (CVD) trajectory, especially among asthmatic subjects. Based on the UK Biobank cohort, we retrieved 292,227 adults free of asthma and CVD aged 37-73 years at recruitment (2006-2010). Annual mean concentrations of particulate matter (PM10 and PM2.5) and nitrogen oxides (NO2 and NOx) were assessed at each individual's addresses. We used multi-state models to estimate the associations of air pollution with the trajectory from healthy to incident asthma, subsequent CVD, and death. During a median follow-up of 11.7 years, a total of 6338 (2.2%) participants developed asthma, among which, 638 (10.1%) subsequently proceeded to CVD. We observed significant impacts of various air pollutants on the CVD dynamic transitions, with a more substantial effect of particulate matter pollutants than gaseous air pollutants. For example, the hazard ratios (95% confidence intervals) for per interquartile range increase in PM2.5 and PM10 were 1.28 (1.13, 1.44) and 1.27 (1.13, 1.43) for transitions from incident asthma to subsequent CVD. In conclusion, long-term air pollution exposure could affect the CVD trajectory. Distinguishing the effect of air pollutants on CVD transition stages has great significance for CVD health management and clinical prevention, especially among asthma patients.

Ultra-processed food consumption, mediating biomarkers, and risk of chronic obstructive pulmonary disease: a prospective cohort study in the UK Biobank

Background: Ultra-processed food (UPF) is a popular supplement in the UK and other developed countries. However, whether and how UPF intake is associated with chronic obstructive pulmonary disease (COPD) remains unclear. Objective: We aimed to examine the association between UPF consumption and COPD incidence and explore the potential mediating effects of COPD-related biomarkers. Methods: This prospective cohort study included 207 002 participants without COPD at recruitment and completed 24-hour dietary recalls. UPF was defined according to the NOVA classification system. Incident COPD was ascertained using electronic hospital and mortality records. Cox regression models were used to estimate UPF consumption and the subsequent risk of COPD. Substitution analysis was performed to assess the risk of COPD by substituting UPF with an equivalent proportion of unprocessed or minimally processed food (UNPF). Mediation analyses were performed to evaluate the contribution of biomarkers related to the lipid profile, glucose metabolism, and systemic inflammation to the observed associations. Results: During a median follow-up of 13.1 (interquartile range: 12.5-13.9) years, 4670 COPD events were recorded. The adjusted hazard ratio (HR) of COPD in the highest quintile versus the lowest quintile of the UPF consumption proportion (weight percentage of the UPF) was 1.22 (95% confidence interval [CI]: 1.11-1.34). There was a 10% elevated risk of COPD incidence per SD increase in UPF intake (HR: 1.10; 95% CI: 1.08-1.13). Replacing 20% of the UNPF weight with the UPF was associated with a 13% decrease in COPD risk (95% CI: 0.84-0.91). In mediation analyses, biomarkers explained 1.0-10.1% of the association between UPF intake and COPD. Results from stratified and sensitivity analyses further support the robustness of these findings. Conclusions: Elevated UPF consumption was associated with a higher risk of COPD, and this association was primarily mediated by glucose, inflammation, and lipids, whereas substituting UNPF for UPF was associated with a decreased risk of COPD.

The Effects of Wildfire Smoke on Asthma and Allergy

PURPOSE OF REVIEW

To review the recent literature on the effects of wildfire smoke (WFS) exposure on asthma and allergic disease, and on potential mechanisms of disease.

RECENT FINDINGS

Spatiotemporal modeling and increased ground-level monitoring data are allowing a more detailed picture of the health effects of WFS exposure to emerge, especially with regard to asthma. There is also epidemiologic and some experimental evidence to suggest that WFS exposure increases allergic predisposition and upper airway or sinonasal disease, though much of the literature in this area is focused more generally on PM2.5 and is not specific for WFS. Experimental evidence for mechanisms includes disruption of epithelial integrity with downstream effects on inflammatory or immune pathways, but experimental models to date have not consistently reflected human disease in this area. Exposure to WFS has an acute detrimental effect on asthma. Potential mechanisms are suggested by in vitro and animal studies.