Increase In Fractional Exhaled Nitric Oxide Research Articles

The Association Between Personal Air Pollution Exposures and Fractional Exhaled Nitric Oxide (FeNO): A Systematic Review.

Airway inflammation is a common biological response to many types of environmental exposures and can lead to increased nitric oxide (NO) concentrations in exhaled breath. In recent years, several studies have evaluated airway inflammation using fractional exhaled nitric oxide (FeNO) as a biomarker of exposures to a range of air pollutants. This systematic review aims to summarize the studies that collected personal-level air pollution data to assess the air pollution-induced FeNO responses and to determine if utilizing personal-level data resulted in an improved characterization of the relationship between air pollution exposures and FeNO compared to using only ambient air pollution exposure data. Thirty-six eligible studies were identified. Overall, the studies included in this review establish that an increase in personal exposure to particulate and gaseous air pollutants can significantly increase FeNO. Nine out of the 12 studies reported statistically significant FeNO increases with increasing personal PM2.5 exposures, and up to 11.5% increase in FeNO per IQR increase in exposure has also been reported between FeNO and exposure to gas-phase pollutants, such as ozone, NO2, and benzene. Furthermore, factors such as chronic respiratory diseases, allergies, and medication use were found to be effect modifiers for air pollution-induced FeNO responses. About half of the studies that compared the effect estimates using both personal and ambient air pollution exposure methods reported that only personal exposure yielded significant associations with FeNO response. The evidence from the reviewed studies confirms that FeNO is a sensitive biomarker for air pollutant-induced airway inflammation. Personal air pollution exposure assessment is recommended to accurately assess the air pollution-induced FeNO responses. Furthermore, comprehensive adjustments for the potential confounding factors including the personal exposures of the co-pollutants, respiratory disease status, allergy status, and usage of medications for asthma and allergies are recommended while assessing the air pollution-induced FeNO responses.

Traffic-related air pollution, chronic stress, and changes in exhaled nitric oxide and lung function among a panel of children with asthma living in an underresourced community

We examined associations between short-term exposure to traffic-related air pollutants (TRAP) and airway inflammation and lung function in children with asthma, and whether these associations are modified by chronic psychological stress. Residents of underresourced port-adjacent communities in New Jersey were concerned about the cumulative impacts of exposure to TRAP, particularly diesel-engine truck emissions, and stress on exacerbation of asthma among children. Children with asthma aged 9–14 (n = 35) were recruited from non-smoking households. We measured each participant's (1) continuous personal exposure to black carbon (BC, a surrogate of TRAP) at 1-min intervals, (2) 24-h integrated personal exposure to nitrogen dioxide (NO2), (3) daily fractional exhaled nitric oxide (FeNO), and (4) lung function for up to 30 consecutive days. Personal BC was recorded by micro-aethalometers. We measured daily FeNO using the NIOX MINO, forced expiratory volume in one second (FEV1), and forced vital capacity (FVC) using Easy One Frontline spirometers. Chronic stress was measured with the UCLA Life Stress Interview for Children. The association was examined using linear mixed-effect models. In the fully adjusted model, an interquartile range (IQR) increase in BC at lag 0–6 h before the FeNO measurement was associated with 8 % (95 % CI: 3 % - 12 %) increase in FeNO, whereas an IQR increase in BC at lag 7–12 h and lag 0–24 h were associated with 6 % (95 % CI: 2 % - 11 %) and 7 % (2 % - 12 %) FeNO increases, respectively. There were no significant lung function changes per IQR increase in BC. No interactions were observed between chronic stress and BC on FeNO. Chronic stress was negatively associated with individual average FeNO levels. Our findings suggest that higher levels of BC exposure within the prior 24 h increased airway inflammation levels in children with asthma, with the strongest effect observed within the first 6 h.

Association of size-fractionated particulate matters and their chemical constituents with airway inflammation and lung function among healthy children: A panel study

BackgroundEvidence is limited regarding size-fractionated particulate matters and their constituents responsible for children's respiratory health. ObjectiveTo investigate the short-term effects of size-fractionated particle number counts (PNCs) and their chemical constituents on airway inflammation and lung function in healthy children. MethodsWe conducted a longitudinal panel study involving 3 repeated surveys among 144 children aged 4–12 years in Guangzhou, China. Lung function and the fractional exhaled nitric oxide (FeNO) were measured during each visit. The real-time multi-size PNCs and their 23 constituent counts were obtained from the environmental monitoring station. We applied linear mixed-effects (LME) models, least absolute shrinkage and selection operator (LASSO) regression, and Bayesian kernel machine regression (BKMR) to evaluate the associations. ResultsEach interquartile range (IQR) increase in PNC0.5 was dose-responsive associated with 10.46% (95% CI: 2.54%, 18.98%) increase in FeNO at lag 0 day and 1.12% (95% CI: -1.90%, −0.33%) decrease in the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) at lag 1 day. But results for PNC1.0 and PNC2.5 were not significant. In LASSO regression models, K+, NH4+, and HSO4− were important predictors for FeNO, while Mg+, NH4+, and Mn+ were significant predictors for FEV1/FVC. Additionally, the overall effects of constituent mixture on higher FeNO or lower FEV1/FVC were robust when the mixture was above the 55th or 65th percentiles in PNC0.5 compared to the median. And a significant association between exposure to NH4+ and FeNO increment was identified, when setting all other constituents at the 25th, 50th and 75th percentiles. ConclusionShort-term exposure to PNC0.5 was dose-responsive related to increased FeNO and decreased FEV1/FVC among healthy children, and NH4+ in PNC0.5 might play a more dominant role in airway inflammation.

Ambient Environmental Ozone and Variation of Fractional Exhaled Nitric Oxide (FeNO) in Hairdressers and Healthcare Workers

Fractional exhaled nitric oxide (FeNO) is a breath-related biomarker of eosinophilic asthma. The aim of this study was to investigate FeNO variations due to environmental or occupational exposures in respiratory healthy subjects. Overall, 14 hairdressers and 15 healthcare workers in Oslo were followed for 5 workdays. We registered the levels of FeNO after commuting and arriving at the workspace and after ≥3 h of work, in addition to symptoms of cold, commuting method, and hair treatments that were performed. Both short- and intermediate-term effects after exposure were evaluated. Environmental assessment of daily average levels of air quality particulate matter 2.5 (PM2.5), particulate matter 10 (PM10), nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3) indicated a covariation in ozone and FeNO in which a 35-50% decrease in ozone was followed by a near 20% decrease in FeNO with a 24-h latency. Pedestrians had significantly increased FeNO readings. Symptoms of cold were associated with a significant increase in FeNO readings. We did not find any FeNO increase of statistical significance after occupational chemical exposure to hair treatments. The findings may be of clinical, environmental and occupational importance.

Evaluation of lung inflammation from daily exposures to fine and ultrafine particulate matter in a trade school

Background - Daily short-term exposure to ambient fine particles (PM₂.₅ ; < 2.5 μm) in the general environment has been related to acute respiratory effects such as respiratory symptoms and inflammation, emergency room visits for respiratory conditions and mortality. Although exposure is higher in trade/occupational settings, acute respiratory effects of daily exposures remain unexplored. Objective - To evaluate the association between daily exposures to fine particles (PM₂.₅) and Ultrafine Particles (UFP; < 0.1 μm), and fractional exhaled nitric oxide (FeNO), a relevant indicator of lung inflammation, in two trade settings from a construction school. Method - A repeated-measure panel study was carried out on students performing welding and bricklaying activities (n=30). PM₂.₅ and UFP concentrations were measured daily (area measurements with direct-reading instruments) and fractional exhaled FeNO were measured two times per day, pre-work and post-work, for 5 consecutive days. Mixed GLM models were used to assess associations. Results - Daily geometric mean exposure to PM₂.₅ from welding and bricklaying activities were respectively 183 μg/m³ (σg=3.5) and 90.8 μg/m³ (σg=1.6). Daily geometric mean UFP concentrations for these activities were 106,000 (σg=1.6) particles/cm³ and 4,400 (σg=1.7) particles/cm³. Combining bricklaying and welding activities, for a 10,000 particles/cm³ increase in UFP, there was a 0.2 ppb (95%CI: 0.05-0.3) increase in FeNO inter-day. There was also a tendency for a small increase in FeNO (0.2 ppb; 95%CI: -0.06 - 0.5) per 100 µg/m³ of PM₂.₅ . Further analyses will be performed with additional participants and stratified by occupational trade. Conclusion - Bricklaying and welding activities expose workers daily to PM₂.₅ and UFP that may contribute to recurrent pulmonary inflammation and impair respiratory health. Keywords: particulate matter, occupational exposures, short-term exposure, pulmonary inflammation.

Fractional Exhaled Nitric Oxide in Teenagers and Adults with Atopic Dermatitis.

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic airway inflammation and therapeutic response to corticosteroid treatment of respiratory diseases. Atopic dermatitis (AD), one of the most common allergic conditions of the skin, is a factor influencing the increase of FeNO. The main aim of this study was to determine differences between levels of FeNO in patients with AD and healthy controls as measured by an electrochemical analyzer. In total, 54 teenagers and adults with AD were recruited and compared with 34 healthy volunteers. The measurements of FeNO were taken using the Hyp’Air FeNO in participants. FeNO was statistically significantly higher in patients with AD than in healthy controls (60.5 ± 35.1 vs. 14.8 ± 5.1 ppb, p < 0.001). We found a strong positive significant correlation between FeNO and the number of positive skin prick tests among AD patients (R = 0.754, p < 0.001). There was no correlation between FeNO and duration of disease as well as SCORAD index among patients. Moreover, we also found no FeNO difference between the mild and moderate forms of AD. The presence of AD and the increasing number of positive skin prick tests increase FeNO, so the results of this measurement should be interpreted with caution in patients with respiratory diseases suffering from AD.

Airway inflammation in adolescents and elderly women: Chronic air pollution exposure and polygenic susceptibility

Background and aimThe fractional exhaled nitric oxide (FeNO) concentration in the exhaled breath is a biomarker for eosinophilic airway inflammation. We explored the interplay between chronic air pollution exposure and polygenic susceptibility to airway inflammation at different critical age stages. MethodsAdolescents (15 yr) enrolled in the GINIplus/LISA birth cohorts (n = 2434) and 220 elderly women (75 yr on average) enrolled in the SALIA cohort with FeNO measurements available were investigated. Environmental main effects of the mean of ESCAPE land-use regression air pollutant concentrations within a time window of 15 years and main effects of the polygenic risk scores (PRS) using internal weights from elastic net regression of genome-wide derived single nucleotide polymorphisms were investigated. Furthermore, we examined gene-environment interaction (GxE) effects on natural log-transformed FeNO levels by adjusted linear regression models. ResultsWhile we observed no significant environmental and polygenic main effects on airway inflammation in either age group, we found robust harmful effects of chronic nitrogen dioxide (NO2) exposure in the GxE models for elderly women (16.2 % increase in FeNO, p-value = 0.027). Stratified analyses found GxE effects between the PRS and chronic NO2 exposure in never-smoker elderly women and in adolescents without any inflammatory respiratory conditions. ConclusionsFeNO measurement is a useful biomarker to detect higher risk of NO2-induced eosinophilic airway inflammation in the elderly. There was limited evidence for GxE effects on airway inflammation in adolescents or the elderly. Further GxE studies in subpopulations should be conducted to investigate the assumption that susceptibility to airway inflammation differs between age stages.

Association of fractional exhaled nitric oxide with asthma morbidity in urban minority children

Objective Fractional exhaled nitric oxide (FeNO) is a well-established measure of allergic airway inflammation and possible useful adjunct disease management tool. We investigated the association of baseline and follow-up FeNO measurements with disease burden in minority children with persistent asthma. Methods A retrospective chart review was conducted on 352 African American and Hispanic children seen at an urban Asthma Center in Bronx, NY. Demographic, clinical characteristics, and pulmonary function tests (PFTs) were compared between children with low, intermediate, and high baseline FeNO levels. Among 95 children with subsequent follow up visits, associations of change in FeNO with demographics, clinical characteristics, and PFTs were examined using mixed effects linear regression models. Results A higher proportion of children with intermediate (54%) and high FeNO (58%) levels had lower airways obstruction compared to those with low FeNO levels (33%). Children with intermediate FeNO levels had more annual hospitalizations (2.8 ± 6.2) compared to those with low and high FeNO levels (1.3 ± 2.8 and 1.3 ± 2.5). These associations did not differ between ethnicities. An increase in FeNO over time was associated with higher BMI z-scores (β = 6.2, 95% CI: 1.0 to 11.4) and two or more hospitalizations in the past year (β = 16.1, 95% CI: 1.5 to 30.8). Conclusions Intermediate and high FeNO levels are associated with lower airways obstruction and hospitalizations. Initial and serial FeNO measurements can be a useful adjunctive tool in identifying asthma-related morbidity in urban African American and Hispanic children.

Increase in FeNO Levels Following IL5/IL5R-Targeting Therapies in Severe Asthma: A Case Series.

PurposeMonoclonal antibodies targeting interleukin-5 (IL5) and its receptor (IL5R), used for severe asthma treatment, reduce eosinophils to almost complete depletion. Fractional exhaled nitric oxide (FeNO), a surrogate marker of eosinophilic airway inflammation, is expected to decrease after their initiation. Our center noticed increased FeNO levels in a few patients in whom anti-IL5/IL5R therapy was initiated. Limited data are available on the kinetics of T2 inflammation biomarkers after initiation of a biologic in that population. This study aims to identify if a subgroup of severe asthma patients experiences increased FeNO levels after initiation of anti-IL5/IL5R therapy and to describe their clinical characteristics.Patients and MethodsThis is a retrospective case series of 5 patients on Benralizumab (4M:1F) and 8 on Mepolizumab (5M:3F) who showed a significant increase in FeNO (>20% AND >25 ppb) following initiation of an anti-IL5/IL5R treatment. Clinical data, expiratory flows, and inflammation were extracted from the patients’ chart at initiation of treatment (T0), 3 months (T1) and 12 months (T2) post-treatment. Descriptive statistics were used.ResultsIn patients treated with Benralizumab, the increase in FeNO was observed between T0 and T1 (mean delta = 82 ± 72 ppb) with a subsequent decrease (N = 3). In most patients taking Mepolizumab (N = 6), the FeNO increase was observed between T1 and T2 (mean delta = 57 ± 35 ppb). Under treatment, no Benralizumab patient experienced asthma exacerbation while two on Mepolizumab did. All patients had a significant decrease in blood eosinophils.ConclusionAlthough initiation of anti-IL5/IL5R may cause a transient rise in FeNO levels in a subgroup of patients, it does not appear to affect clinical outcomes. A compensatory mechanism involving other inflammatory pathways such as IL13 or IL4, both involved in FeNO production, could theoretically explain these findings. Further investigation is needed to elucidate the actual underlying mechanisms.

Serum vitamin D level mitigates fractional exhaled nitric oxide linked to bisphenol-A in school-aged children.

Previous studies on the relationship of bisphenol-A (BPA) with fractional exhaled nitric oxide (FeNO) had conflicting results, suggesting that other factors may modulate this relationship. Thus, we investigated the modulating effect of vitamin D on the relationship of BPA with FeNO in children. This study recruited 432 children (10 to 12 years old) from the general pediatric population of Korea between June and July 2017. We conducted measurements of urinary BPA, serum vitamin D, specific serum IgE, FeNO, and data from impulse oscillometry (reactance area [AX], airway resistance at 5 Hz [Rrs5] and 20 Hz [Rrs10], and the difference of Rrs5 and Rrs20 [Rrs5-20]). Serum vitamin D (adjusted β =- 0.014, p=0.002) and urinary BPA (β = 0.006, p<0.001) level was significantly associated with FeNO. Urinary BPA level was significantly associated with FeNO in children with low vitamin D levels (≤23 ng/mL; αβ = 0.006, p < 0.001), but not in children with high vitamin D levels (>23 ng/mL). The interaction of vitamin D and BPA had a significant effect on FeNO (pint = 0.005). There was no relationship with the airway lung function (Rrs5, AX, and Rrs5-20) to serum vitamin D and urinary BPA level. Vitamin D ameliorated the BPA-mediated increase of FeNO in children. These results suggest that children with low vitamin D levels may be more susceptible to airway inflammation due to BPA.

Diagnostic possibility of the combination of exhaled nitric oxide and blood eosinophil count for eosinophilic asthma

BackgroundTests to identify reversible airflow limitation are important in asthma diagnosis, but they are time-consuming and it may be difficult for patients to cooperate. We aimed to evaluate whether the combination of fractional exhaled nitric oxide (FeNO) and blood eosinophil (B-Eos) can be used to distinguish some asthma patients who could avoid objective tests.MethodsWe conducted a retrospective cohort study on 7463 suspected asthma cases between January 2014 and December 2019 in Chongqing, China, and identified 2349 patients with complete FeNO, B-Eos count, and spirometry data. Asthma was diagnosed by clinicians by the criteria of recurrent respiratory symptoms and a positive bronchial-provocation or bronchodilation test (BPT, BPD). We evaluated the diagnostic accuracy of FeNO or B-Eos alone or both in combination for asthma using receiver operating characteristic (ROC) curve analysis.ResultsIn this study, 824 patients were diagnosed with asthma. When FeNO and B-Eos counts were used in combination, the area under the ROC curve (AUC) for diagnosing asthma increased slightly (0.768 vs. 0.745 [FeNO] or 0.728 [B-Eos]; both P < 0.001). The odds ratio for having asthma increased progressively with a gradual increase in FeNO or B-Eos count (both P < 0.001; assessed using the Cochran–Armitage trend test). Further analysis of in-series combinations of different threshold values for these biomarkers indicated that moderately elevated biomarker levels (FeNO > 40 ppb and B-Eos > 300 cells/μl) support a diagnosis of asthma because diagnostic specificity was > 95% and the positive likelihood ratio (PLR) was > 10. This conclusion was verified when selecting the 2017–2019 data as the internal validation dataset.ConclusionFeNO or B-Eos count alone is insufficient to accurately diagnose asthma. Patients with moderately elevated biomarkers (FeNO > 40 ppb and B-Eos > 300 cells/μl) could be diagnosed with asthma and avoid objective tests when such tests are not feasible.

Serial measurements of fractional exhaled nitric oxide at home and at work: A useful tool for monitoring workers with platinum salt allergy after exposure reduction.

Serial measurements of fractional exhaled nitric oxide at home and at work: A useful tool for monitoring workers with platinum salt allergy after exposure reduction.

Associations of short-term PM2.5 exposures with nasal oxidative stress, inflammation and lung function impairment and modification by GSTT1-null genotype: A panel study of the retired adults

PM2.5 (particulate matter ≤2.5 μm in aerodynamic diameter) is a major urban air pollutant worldwide. Its effects on the respiratory system of the susceptible population have been less characterized. This study aimed to estimate the association of short-term PM2.5 exposure with respiratory outcomes of the retired adults, and to examine whether these associations were stronger among the subjects with GSTT-null genotype. 32 healthy subjects (55–77 years) were recruited for five follow-up examinations. Ambient concentrations of PM2.5 were monitored consecutively for 7 days prior to physical examination. Pulmonary outcomes including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), and fractional exhaled nitric oxide (FeNO), and nasal fluid concentrations of 8-epi-prostaglandin F2 alpha (8-epi-PGF2α), tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8) and IL-1β were measured. A linear mixed-effect model was introduced to evaluate the associations of PM2.5 concentrations with respiratory outcomes. Additionally, GSTT1 genotype-based stratification was performed to characterize modification on PM2.5-related respiratory outcomes. We found that a 10 μg/m3 increase in PM2.5 was associated with decreases of 0.52 L (95% confidence interval [CI]: -1.04, -0.002), 0.64 L (95% CI: -1.13, -0.16), 0.1 (95% CI: -0.23, 0.04) and 2.87 L/s (95% CI: -5.09, -0.64) in FVC, FEV1, FEV1/FVC ratio and PEF at lag 2, respectively. Meanwhile, marked increases of 80.82% (95% CI: 5.13%, 156.50%) in IL-8, 77.14% (95% CI: 1.88%, 152.40%) in IL-1β and 67.87% (95% CI: 14.85%, 120.88%) in 8-epi-PGF2α were observed as PM2.5 concentration increased by 10 μg/m3 at lag 2. Notably, PM2.5-associated decreases in FVC and PEF and increase in FeNO were stronger among the subjects with GSTT1-null genotype. In summary, short-term exposure to PM2.5 is associated with nasal inflammation, oxidative stress and lung function reduction in the retired subjects. Lung function reduction and inflammation are stronger among the subjects with GSTT1-null genotype.

Effect of continuous positive airway pressure therapy on exhaled nitric oxide and C-reactive protein as markers of inflammation in Egyptian patients with obstructive sleep apnea

Background Obstructive sleep apnea syndrome (OSAS) is associated with the respiratory tract inflammation. Fractional exhaled nitric oxide (FeNO) and high-sensitivity C-reactive protein (Hs-CRP) are indicators of airway and systemic inflammation. Few revisions have explored the effect of continuous positive airway pressure (CPAP) on both indicators in OSAS. Purpose To study the influence of CPAP therapy on exhaled NO and Hs-CRP in OSAS. Patients and methods This is a case–control study that included 27 participants with OSAS and 10 controls enlisted from a sleep outpatient clinic. Full-night polysomnography was performed, and the next morning, FeNO and Hs-CRP were evaluated. CPAP for patients with moderate to severe OSA was advised with measurement of FeNO and Hs-CRP after 3 months of CPAP. Results Both FeNO and Hs-CRP in patients with OSA were statistically significantly increased against the control group. However, after 3 months of CPAP therapy, there was a statistically significant decrease in both FeNO and Hs-CRP. Conclusion Upper airway and systemic inflammation are extant in OSAS, reinforced by increases in both FeNO and CRP, and CPAP therapy diminishes FeNO levels in patients with OSA.

Acute respiratory response to individual particle exposure (PM1.0, PM2.5 and PM10) in the elderly with and without chronic respiratory diseases.

Limited data were on the acute respiratory responses in the elderly in response to personal exposure of particulate matter (PM). In order to evaluate the changes of airway inflammation and pulmonary functions in the elderly in response to individual exposure of particles (PM1.0, PM2.5 and PM10), we analyzed 43 elderly subjects with either asthma, chronic obstructive pulmonary disease (COPD) or Asthma COPD Overlap (ACO) and 40 age-matched subjects without asthma nor COPD in an urban community in Shanghai, China. Data were collected at the baseline and in 6 follow-ups from August 2016 to December 2018, once every 3 months except for the last twice with a 6-month interval. In each follow-up, pulmonary functions, fractional exhaled nitric oxide (FeNO), 7-day continuous personal exposure to airborne particles were measured. Multivariate linear mixed effect regression models were applied to investigate the quantitative changes of pulmonary functions and FeNO in two respective groups. The results showed that on average 4.7 follow-up visits were completed in each participant. In subjects with CRDs, an inter-quartile range (IQR) increase of personal exposure to PM1.0, PM2.5 and PM10 was significantly associated with an average increase of FeNO(Lag1) of 6.7ppb (95%CI 1.2, 9.9ppb), 6.2ppb (95%CI 1.5, 12.0ppb) and 5.6ppb (95%CI 1.5, 11.0ppb), respectively, and an average decrease of FEV1(Lag2) of-3.6L (95%CI -6.0,-1.1L),-3.6L (95%CI -6.4,-0.8L) and-3.2L (95%CI -5.8,-0.6L), respectively, in the single-pollutant model. These associations remained consistent in the two-pollutant models adjusting for gaseous air pollutants. Stratified analysis showed that subjects with lower BMI, females and non-allergies were more sensitive to particle exposure. No robust significant effects were observed in the subjects without CRDs. Our study provided data on the susceptibility of the elderly with CRDs to particle exposure of PM1.0 and PM2.5, and the modification effects by BMI, gender and history of allergies.

Association between exposure to polyfluoroalkyl chemicals and increased fractional exhaled nitric oxide in adults

BackgroundPerfluoroalkyl chemicals (PFCs) are widely detected in the environment and human body, and they have been linked to asthma and a number of respiratory responses in children and mice. However, no previous studies have investigated the association between exposure to PFCs and airway inflammation in adults. ObjectivesTo evaluate the associations between serum PFCs and fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation, in adults. MethodsA cross-sectional study of 3630 adults aged 20–79 years who participated in the National Health and Nutrition Examination Survey (NHANES, 2007–2012) was conducted. Serum concentrations of five major PFCs were measured using SPE-HPLC-TIS-MS/MS method, including perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDE). The detection rates of them were all >85%. Weighted multivariable linear regression and Bayesian kernel machine regression (BKMR) analyses were applied to examine the associations between serum PFCs and FeNO. ResultsAfter adjusted for potential confounding factors, linear regression analyses found that compared with their lowest tertiles, highest tertiles of PFOS, PFDE and PFOA were significantly associated with 5.02% (95% CI: 1.40%, 8.77%), 3.77% (95% CI: 0.30%, 7.36%) and 6.34% (95% CI: 2.81%, 10.01%) increases in FeNO, respectively. The second tertile of PFNA was significantly correlated with a 4.79% (95% CI: 1.41%, 8.29%) increase in FeNO compared with the lowest tertile. In the BKMR analysis, the mixture effect of PFCs on FeNO increased significantly when the PFC levels were at or above the 60th percentiles compared to those at their medians. PFOS and PFOA displayed significant positive single-exposure effects on FeNO when all the other PFCs are set at a particular threshold. ConclusionsThis study provided preliminary evidence that serum PFCs were positively associated with increased FeNO in adults.

Pesticide Urinary Metabolite Concentration and Asthma Morbidity in Socially Disadvantaged Children

Background: Little is known about urinary pesticide (UP) concentration in socially disadvantaged children. These children may be at greater exposure risk because low income is associated with more household pest exposure. Urinary pesticide concentration and its association with asthma morbidity was measured in 161 children with asthma (7-12 years) residing in subsidized housing in three U.S. cities (Boston, Cincinnati, New Orleans).Methods: Morning void and convenience spot samples were collected at three time points over one year. Urine samples were analyzed for seven pesticide metabolites; 3 organophosphates (OPs): TCPY, IMPY, PNP; 3 pyrethroids (PYR): 4-F-3-PBA, 3-PBA, trans-DCCA; and 1 herbicide: 2,4-D. Total PYR was calculated as the sum of 4-F-3PBA, 3-PBA, and trans-DCCA and total OP as the sum of TCPY, IMPY, and PNP. Outcomes were forced expiratory volume in one second (FEV1), and respiratory inflammation measured as fractional exhaled nitric oxide (FeNO).Results: A total of eight hundred and ten urine samples were collected. The proportion with detectable metabolites ranged from 35% (trans-DCCA) to 97% (TCPY and PNP). Geomeans of each pesticide were higher in this cohort compared to a national sample (NHANES 2009-2010) of children 6-11 years. In models adjusting for socio-demographic factors, a 1 µg/mL increase in TCPy, IMPY, trans-DCCA, 2,4-D, total OPs and PNP was associated with a reduction in FEV1 (-0.004 to -0.158) although no model reached statistical significance (p&lt;0.05). An increase in TCPY, total OPs, and 4-F-3-PBA, resulted in a non-statistically significant increase in FeNO (0.0004 to 0.0675) .Conclusion: Results demonstrate these low-income children with asthma residing in subsidized housing are exposed to higher concentrations of pesticides compared to a general population sample. Additionally, the evidence suggests negative respiratory outcomes with increasing levels of UPs. Reducing exposure to pesticides is important to mitigate the potential negative health effects for vulnerable populations.

Susceptibility of individuals with chronic obstructive pulmonary disease to respiratory inflammation associated with short-term exposure to ambient air pollution: A panel study in Beijing

BackgroundChronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. There is no clear evidence of whether COPD patients are more susceptible to respiratory inflammation associated with short-term exposure to air pollutants than those without COPD. ObjectivesThis study directly compared air pollutant-associated respiratory inflammation between COPD patients and healthy controls. MethodsThis study is based on the COPDB panel study (COPD in Beijing). Fractional exhaled nitric oxide (FeNO) was repeatedly measured in 53 COPD patients and 82 healthy controls at up to four clinical visits. Concentrations of carbon monoxide (CO), nitrogen monoxide, nitrogen dioxide (NO2), sulfur dioxide (SO2), fine particulate matter (PM2.5), black carbon (BC), ultrafine particles (UFPs), and accumulated-mode particles (Acc) were monitored continuously at a fixed-site monitoring station. Linear mixed-effects models were used to compare the associations between ln-transformed FeNO and average 1–23 h concentrations of air pollutants before the clinical visits. ResultsFeNO was positively associated with interquartile range (IQR) increases in average concentrations of CO, NO2, SO2, BC, UFPs, and Acc in all participants, with the strongest associations in different time-windows (range from 6.6% for average 1 h NO2 exposure to 32.1% for average 7 h SO2 exposure). Associations between FeNO and average 13–23 h PM2.5 exposure differed significantly according to COPD status. Increases in FeNO associated with average 1–2 h NO exposure were significant in COPD patients (range 8.9–10.2%), while the associations were nonsignificant in healthy controls. Associations between FeNO and average 1–23 h CO and SO2 exposure tended to be higher in COPD patients than in healthy controls, although the differences were not significant. UFPs-associated respiratory inflammation was robust in both subgroups. ConclusionsCOPD patients are more susceptible to respiratory inflammation following PM2.5, NO, CO, and SO2 exposure than individuals without COPD.

Monitoring metrics for short-term exposure to ambient ozone and pulmonary function and airway inflammation in healthy young adults

To assess the associations of different monitoring metrics for short-term exposure to ambient ozone (O3) with pulmonary function and airway inflammation in healthy young adults. A total of 97 healthy young college students were recruited and followed in a panel study conducted from December 2017 to June 2018. Each participant underwent 3 follow-up visits, and lung function and fractional exhaled nitric oxide (FeNO) were measured at each visit. Ambient air pollutant concentrations were obtained from the environment monitoring station of Beijing closest to the participant residences, and meteorological data were collected from China Meteorological Data Service Center. Linear mixed-effect models were applied to assess the associations between different monitoring metrics for ambient O3 short-term exposure with pulmonary function or airway inflammation in the healthy young adults. During the study period, the P50 (P25, P75) values for ambient O3 concentration expressed as daily 1-hour maximum (O3-1 h max), daily maximum 8-hour average (O3-8 h max) and 24-hour average (O3-24 h avg) were 102.5 (76.8, 163.0) μg/m3, 91.1 (68.3, 154.3) μg/m3 and 61.6 (36.9, 81.7) μg/m3, respectively. The different monitoring metrics for short-term exposure to ambient O3 were significantly associated with reduced forced expiratory volume in the first second (FEV1) and increased FeNO. An interquartile range (IQR) increase in 6-d moving average of O3-1 h max (IQR=71.5 μg/m3) was associated with a 6.2% (95%CI: －11.8%, －0.5%) decrease in FEV1 and a 63.3% (95%CI: 13.8%, 134.3%) increase in FeNO. An IQR increase in 7-d moving average of O3-8 h max (IQR=62.0 μg/m3) was associated with a 6.2% (95%CI: －11.6%, －0.7%) decrease in FEV1and a 75.5% (95%CI: 19.3%, 158.0%) increase in FeNO. An IQR increase in 5-d moving average of O3-24 h avg (IQR=32.9 μg/m3) was associated with a 3.7% (95%CI: －7.1%, －0.2%) decrease in FEV1and a 25.3% (95%CI: 3.6%, 51.6%) increase in FeNO. There was no significant association between the three monitoring metrics for O3 exposure and peak expiratory flow (PEF). Short-term exposure to ambient O3 was associated with decreased lung function and increased airway inflammation among the healthy young adults, and daily 1-hour maximum was more sensitively to the respiratory effects of O3.

Associations between source-resolved PM2.5 and airway inflammation at urban and rural locations in Beijing

BackgroundA large number of research studies have explored the health effects of exposure to atmospheric particulate matter. However, limited quantitative evidence has linked specific sources of personal PM2.5 directly to adverse health effects. This study was conducted in order to examine the association between airway inflammation and personal exposure to PM2.5 mass, components, and sources among two healthy cohorts living in both urban and rural areas of Beijing, China. MethodsWe conducted a follow-up study during the summer of 2016 and the winter of 2016/2017 among 92 students and 43 guards. 24-h personal and ambient exposure to PM2.5 and fractional exhaled nitric oxide (FeNO) were measured at least twice for each participant. Chemical components of 385 personal PM2.5 exposure samples were analyzed, and pollution sources were resolved by a positive matrix factorization (PMF) receptor model. We have constructed linear mixed effect models to evaluate the association between ambient/personal PM2.5 mass, chemical constituents, and source specific PM2.5 with FeNO after controlling for temperature, relative humidity, sites, season, and potential individual confounders. ResultsInterquartile range (IQR) increase in household heating sources was associated with increased FeNO (2.72%; 95% CI = 1.26–4.17%) across two sites. IQR increase in roadway transport was associated with increased FeNO (9.84%; 95% CI = 2.69–17%) in urban areas; IQR increase in Secondary inorganic sources and Industrial/Combustion sources were associated with increased FeNO (7.96%; 95% CI = 1.47–14.4%% and 7.85%; 95% CI = 0.0676–15.6%, respectively) in rural areas. Personal exposure to EC, OC, and some trace elements (Se, Pb, Bi, Cs) were also estimated to be significantly associated with the increase of FeNO. In addition, there was no significant difference (P > 0.05) between the effects of ambient and personal PM2.5 mass. ConclusionsAlthough personal PM2.5 mass was not significantly associated with the health effects, airway inflammation can be linked to source-resolved exposures.