Higher Fractional Exhaled Nitric Oxide Research Articles

Validation of ATS clinical practice guideline cut-points for FeNO in asthma.

The American Thoracic society (ATS) has suggested using fractional exhaled nitric oxide (FeNO) to monitor the level of eosinophilic (EOS) airway inflammation in asthma, but validation of the proposed cut-points is required in real-life populations. To validate FeNO cut-points suggested by ATS in relation to sputum EOS count in a real life population of asthma patients. All patients referred consecutively over a 12-months period for specialist assessment of asthma, were examined with FeNO and induced sputum, and re-examined 12 months later. The predicted values of a positive and a negative test (PPV and NPV) for a cut off ≥3% EOS in sputum were calculated. Change in FeNO was defined in accordance with ATS (>20% or 10 ppb if FeNO was <50 ppb). 144 adult asthma patients were examined (59% female). Low FeNO (<25 ppb) at baseline was found in 94 (65%), FeNO between 25 and 50 ppb in 34 (24%) subjects and high FeNO >50 ppb in 16 (11%) subjects. The PPV for FeNO >25 ppb and >50 ppb to predict EOS ≥3% was 45% and 77%, NPV was 88% and 83%. The sensitivity decreased from 70% to 37% at the >50 ppb cut-off. A significant reduction in FeNO was associated with a reduction in sputum EOS (p = 0.01). The findings support the validity of the FeNO cut-points suggested by ATS to monitor eosinophilic airway inflammation in asthma. However, in this real-life population, a large proportion of patients had intermediate FeNO values, which may limit the clinical usefulness of the ATS FeNO cut-points.

Respiratory symptoms, asthma and levels of fractional exhaled nitric oxide in schoolchildren in the industrial areas of Estonia

ObjectivesExposure to air pollutants in the ambient environment has been associated with various respiratory symptoms, and with increased asthma diagnosis, in both children and adults. Most research to date has focussed on core pollutants, such as PM10, PM2.5, SO2 and NO2, and less attention has been given to the effects of industry-specific contamination. The current study aimed to examine the associations between respiratory symptoms, asthma, increased levels of fractional exhaled nitric oxide (FeNO) (as a marker of eosinophilic airway inflammation) and ambient levels of industrial pollutants (such as benzene, phenol, formaldehyde and non-methane hydrocarbons) for schoolchildren living near oil shale industries in Ida-Viru County, Estonia. MethodsA total of 1326 schoolchildren from Ida-Viru, Lääne-Viru and Tartu Counties participated in a cross-sectional study, consisting of questionnaires on respiratory symptoms and asthma, as well as clinical examinations to measure FeNO. Dispersion modelling was used to characterize individual-level exposure to industrial air pollutants at each subject's home address. Associations between exposure and respiratory health were investigated using logistic regression analysis, and differences in results between regions were analysed using the Chi-squared test. ResultsThe prevalence of respiratory symptoms (p < 0.05) in children living near (i.e. within 5 km) of an oil shale industry site in Ida-Viru County was 2–4 times higher than in children living in the reference area of Tartu County. Children exposed to 1 μg/m3 higher levels of benzene and formaldehyde had a higher odds ratio (OR) of having rhinitis without a cold (OR 1.03, 95% confidence interval (CI) 1.01–1.06), of ever having had attacks of asthma (OR 1.05, 95% CI 1.01–1.10) and of having a dry cough a few days per year (OR 1.05, 95% CI 1.01–1.10). Children exposed to 1 μg/m3 higher levels of benzene, formaldehyde, phenol and non-methane hydrocarbons had a higher odds ratio of having high FeNO levels (≥30 ppb): OR and 95% CI of 1.05, 1.01–1.09; 1.22, 1.06–1.41; 1.01, 1.00–1.01; and 1.75, 1.75–2.62, respectively.

Relation of Prenatal Air Pollutant and Nutritional Exposures with Biomarkers of Allergic Disease in Adolescence

Prenatal exposures may be critical for immune system development, with consequences for allergic disease susceptibility. We examined associations of prenatal exposures (nutrient intakes and air pollutants) with allergic disease biomarkers in adolescence. We used data from 857 mother-child pairs in Project Viva, a Massachusetts-based pre-birth cohort. Outcomes of interest at follow-up (median age 12.9 years) were fractional exhaled nitric oxide (FeNO) and total serum IgE. We applied Bayesian Kernel Machine Regression analyses to estimate multivariate exposure-response functions, allowing for exposure interactions. Exposures were expressed as z-scores of log-transformed data and we report effects in % change in FeNO or IgE z-score per increase in exposure from the 25th to 75th percentile. FeNO levels were lower with higher intakes of prenatal vitamin D (−16.15%, 95% CI: −20.38 to −2.88%), folate from foods (−3.86%, 95% CI: −8.33 to 0.83%) and n-3 PUFAs (−9.21%, 95% CI −16.81 to −0.92%). Prenatal air pollutants were associated with higher FeNO and IgE, with the strongest associations detected for PM2.5 with IgE (25.6% increase, 95% CI 9.34% to 44.29%). We identified a potential synergistic interaction (p = 0.02) between vitamin E (food + supplements) and PM2.5; this exposure combination was associated with further increases in FeNO levels.

New asthma testing enhances the care of respiratory patients

New asthma testing enhances the care of respiratory patients

Environmental exposure to polycyclic aromatic hydrocarbons, kitchen ventilation, fractional exhaled nitric oxide, and risk of diabetes among Chinese females.

Diabetes is related to exposure to polycyclic aromatic hydrocarbons (PAHs), inflammation in the body, and housing characters. However, associations of urinary monohydroxy-PAHs (OH-PAHs) or fractional exhaled nitric oxide (FeNO) with diabetes risk in relation to housing characters are unclear. In this study, 2645 individuals were drawn from the baseline survey of the Wuhan-Zhuhai Cohort Study. Associations of diabetes with urinary OH-PAHs or FeNO among cooking participants were estimated using logistic regression models. Among women with self-cooking meals, urinary OH-PAH levels were positively associated with diabetes risk (P<.05); the cooking women with high FeNO (≥25ppb) had a 59% increase in the risk of diabetes (OR: 1.59, 95% CI: 1.06, 2.38), compared with those with low FeNO (<25ppb). The cooking women with use of kitchen exhaust fans/hoods had a 52% decrease in the risk of diabetes (OR: 0.48, 95% CI: 0.27, 0.84), compared with those with nonuse of kitchen exhaust fans/hoods. The results indicated that the cooking women had an elevated risk of diabetes, which may be partly explained by an increase in the PAH body burden and higher inflammatory responses. Use of kitchen exhaust fan/hood can be associated with a lower risk of diabetes.

The Dietary Inflammatory Index and Current Wheeze Among Children and Adults in the United States

A proinflammatory diet may increase allergic airway inflammation by affecting innate and adaptive immune responses. In this study, we examine the relation between the diet's inflammatory potential, measured by the Dietary Inflammatory Index (DII), and current asthma, current wheeze, and lung function in U.S. children and adults. We analyzed data from 8,175 children (aged 6-17 years) and 22,294 adults (aged 18-79 years) who participated in the 2007-2012 National Health and Nutrition Examination Survey. The DII was calculated by nutrient intake based on 24-hour dietary recalls, and normalized as per 1,000 calories of food consumed to account for total energy intake. Multivariable regression models were used for the analysis of the DII and current asthma, current wheeze, and lung function measures. Higher DII (a proinflammatory diet) was associated with current wheeze among adults (eg, odds ratio [OR] for quartile 4 vs 1, OR= 1.41, 95% confidence interval [CI]=1.17-1.70; Ptrend < .01) and among children with high fractional exhaled nitric oxide (a marker of eosinophilic airway inflammation; OR= 2.38, 95% CI= 1.13-5.02; Ptrend= .05). The DII also was associated with decreased forced expiratory volume in 1 second and forced vital capacity in adults without asthma or wheezing. The DII was not associated with lung function in children or current asthma in either age group. Our findings suggest that a proinflammatory diet, assessed by the DII, increases the odds of current wheeze in adults and children with allergic (atopic) wheeze. These results further support testing dietary interventions as part of the management of asthma.

The Value of Fractional Exhaled Nitric Oxide and Forced Mid-Expiratory Flow as Predictive Markers of Bronchial Hyperresponsiveness in Adults with Chronic Cough

Bronchial provocation tests are standard for diagnosing the etiology of chronic cough, but they are time consuming and can induce severe bronchospasm. A safer and faster clinical examination to predict bronchial hyperresponsiveness (BHR) is needed. The objective of this study was to investigate whether small-airway function tests can predict BHR in adult patients with chronic cough. A retrospective, cross-sectional study of diagnoses made using spirometry and bronchial provocation test results was performed in 290 patients with chronic nonproductive cough. BHR-predictive values were analyzed via the area under receiver operating characteristic curves (AUCs). Optimal cutoff values were determined by maximizing the sum of sensitivity and specificity. Patients with chronic cough with BHR showed lower forced expiratory flow between 25% and 75% (FEF25%-75%), higher fractional exhaled nitric oxide (FENO), and a higher percentage of eosinophils in blood than patients without BHR (P < .0001 for all). The AUCs of FENO and FEF25%-75% for a BHR diagnosis were 0.788 (95% CI, 0.725-0.851) and 0.702 (95% CI, 0.641-0.763), respectively. Optimal cutoff values were 43 ppb for FENO and 78.5% for FEF25%-75%, with negative predictive values of 85.38% and 81.34%, respectively. The combined use of FENO and FEF25%-75% increased the AUC to 0.843 (95% CI, 0.794-0.892), significantly higher than either FENO (P= .012) or FEF25%-75% (P < .0001) alone. Small-airway dysfunction is present in patients with chronic cough and BHR. FEF25%-75% has value as a negative predictive parameter for BHR, especially when combined with FENO. FENO > 43 ppb and FEF25%-75% <78.5% strongly predicted a positive bronchial provocation test.

Influence of Maternal Body Mass Index and Macrophage Activation on Asthma Exacerbations in Pregnancy

Obesity is a risk factor for exacerbations of asthma, but the mechanisms of this effect in pregnancy are unknown. This study determined the influence of maternal body mass index, gestational weight gain, eosinophilic inflammation, and systemic macrophage activation on the risk of exacerbations during pregnancy. Women with asthma (n= 164) participated in the study. Body mass index recorded at baseline (17 weeks gestation) was categorized as healthy weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), or obese (>30 kg/m2). Exacerbations requiring medical intervention were recorded prospectively. Asthma control, medication use, and fractional exhaled nitric oxide were assessed monthly; additional visits occurred during exacerbations. Peripheral blood was collected at baseline for the measurement of eosinophils, soluble CD-163, C-reactive protein, and IL-6. Exacerbations occurred in a higher proportion of overweight (51.1%) and obese (48.4%) women compared with healthy weight women (25%; P= .026). Excess weight gain during pregnancy was not associated with exacerbation risk. Macrophage activation (elevated serum soluble CD-163) was associated with exacerbations requiring oral corticosteroids (P=.043), whereas high peripheral blood eosinophils or fractional exhaled nitric oxide were not associated with exacerbation or oral corticosteroid use. Being overweight or obese confers a greater risk of asthma exacerbation during pregnancy, and may be due to systemic macrophage activation.

Exhaled nitric oxide, pulmonary function, and disease activity in children with systemic lupus erythematosus.

To determine the association among fractional exhaled nitric oxide (FENO), pulmonary function, and disease activity in children with systemic lupus erythematosus (SLE). Children aged 7-18 years, diagnosed with SLE under the criteria of the American Rheumatism Association (revised 2012), were enrolled. All eligible participants had disease activity, FENO, and pulmonary function evaluated and re-evaluated at 6-month follow-up. Twenty-four children (95.8% female; mean age 15.2 ± 2 years; median disease duration 2.4 years) were studied. The mean FENO1 and FENO2 were 19.6 ± 7.2 parts per billion (ppb) and 17.4 ± 4.5 ppb, respectively. At baseline, 20.8% had abnormal pulmonary functions (all restrictive defects) and increased to 29.2% at follow-up (isolated restrictive defect 25% and restrictive with diffusion defect 4.2%). Most of their disease activities at baseline and second assessment were non-active (58.3%, 70.8%) or mild disease activities (20.8% both). There was significant correlation between FENO and disease activity (r = 0.49; P-value = 0.02). The significant negative correlation between total lung capacity (TLC) and disease activity was detected in children with active SLE (r = -0.71; P-value = 0.02). Decreased TLC and high FENO were common in SLE children who had no respiratory symptoms and correlated with disease activity. FENO should be considered as an additional pulmonary function to evaluate disease activity in children with SLE.

Prevalence of high fractional exhaled nitric oxide among US youth with asthma.

High fractional exhaled nitric oxide (FeNO) is an indicator of poor asthma control and has been proposed as a non-invasive assessment tool to guide asthma management. We aimed to describe the prevalence of and factors associated with high FeNO among US youth with asthma. Data from 716 children and adolescents with asthma ages 6-19 years who participated in the 2007-2012 National Health and Nutrition Examination Survey were analyzed. Using American Thoracic Society guidelines, high FeNO was defined as >50 ppb for ages 12-19 years and >35 ppb for ages 6-11 years. Multivariate logistic regression examined associations between high FeNO and age, sex, race/Hispanic origin, income status, weight status, tobacco smoke exposure, and other factors associated with asthma control (recent use of inhaled corticosteroids, recent respiratory illness, asthma-related respiratory signs/symptoms, and spirometry). About 16.5% of youth with asthma had high FeNO. The prevalence of high FeNO was higher among non-Hispanic black (27%, P < 0.001) and Hispanic (20.2%, P = 0.002) youth than non-Hispanic white (9.7%) youth. Differences in high FeNO prevalence by sex (girls < boys), weight status (obese < normal weight), tobacco smoke exposure (smokers < home exposure < no exposure), and FEV1/FVC (normal < abnormal) were also observed. No differences were noted between categories for the remaining covariates. High FeNO was observed to be associated with sex, race/Hispanic origin, weight status, tobacco smoke exposure, and abnormal FEV1/FVC, but was not associated with asthma-related respiratory symptoms. These findings may help inform future research and clinical practice guidelines on the use of high FeNO in the assessment of asthma control.

Higher fractional exhaled nitric oxide and Der p 1 exposure in children with asthma living in tropical environments

Higher fractional exhaled nitric oxide and Der p 1 exposure in children with asthma living in tropical environments

Characteristics of non-smoking adult asthma patients with chronic airflow limitation

ABSTRACTObjective: Chronic airflow limitation (CAL) can develop in a subgroup of patients with asthma. Characterising these patients is important because reduced lung function is a risk factor for adverse asthma outcomes. We hypothesised that heterogeneity in patients with CAL may be influenced by age at asthma onset. We first compared never-smoking asthma patients with and without CAL, and subsequently examined the differences between patients with late and early-onset asthma within the CAL cohort. Methods: Patients seen in our hospital's respiratory clinic between 1 Jan 2015 and 31 December 2015 were recruited to the study. CAL was defined as post-bronchodilator forced expiratory volume in 1 second (FEV1)<80% predicted, in the presence of post-bronchodilator ratio <70%. Variables independently associated with CAL were determined using a multivariate logistic regression model. Comparisons between patients with late-onset asthma (age ≥18 years) and early-onset asthma were made within the CAL cohort. Results: 247 patients were included in the study. Age was the only variable independently associated with CAL after regression analysis, with an increase in odds of 3.8% (95% CI 0.4–7.3%) for every 1 year increase in age, p = 0.027. 63.2% of patients with CAL had late-onset asthma. Compared to patients with early-onset asthma, those with late-onset asthma had higher fractional exhaled nitric oxide levels (43 ± 32 ppb vs 20 ± 8 pb, p = 0.008). Conclusions: An increase in age is associated with CAL in never-smoking asthma patients. In addition, age at asthma onset appears to influence airway inflammation in patients with CAL.

Rapid adiposity growth increases risks of new-onset asthma and airway inflammation in children.

We aim to (1) examine the influence of long-term adiposity status/short-term adiposity changes on asthma with high or low fractional exhaled nitric oxide (FeNO), and (2) to determine the differences in long-term adiposity status/short-term adiposity changes on atopy, airway inflammation and pulmonary function. We recruited 2450 fourth- to sixth-grade children from the nationwide Taiwan Children Health Study. Data regarding various adiposity indicators, atopic status, pulmonary function tests and asthma outcomes were collected annually. New-onset asthma was stratified by airway inflammation status using FeNO. The generalized estimating equation was used for analyzing longitudinal relationships between long-term adiposity status/short-term adiposity changes and new-onset asthma. Individual adiposity growth slopes were obtained using a hierarchical linear model to establish the relationships between short-term adiposity changes and asthma among children with high airway inflammation. We found long-term adiposity status predicted childhood asthma with low FeNO, whereas short-term adiposity changes may increase risks of childhood asthma with high FeNO. Long-term adiposity status reduced pulmonary function, whereas short-term adiposity increase were associated with atopic diseases and airway inflammation. Obesity-induced asthma could be mediated by high or low airway inflammation, depending on the velocity of increase in adiposity. Rapid adiposity growth may increase risks of childhood asthma and airway inflammation.

Accuracy of maximal expiratory flow-volume curve curvilinearity and fractional exhaled nitric oxide for detection of children with atopic asthma.

PurposeAirway pathology in children with atopic asthma can be reflected by the concave shape of the maximal expiratory flow-volume (MEFV) curve and high fractional exhaled nitric oxide (FeNO) values. We evaluated the capacity of the curvilinearity of the MEFV curve, FeNO, and their combination to distinguish subjects with atopic asthma from healthy individuals.MethodsFeNO and angle β, which characterizes the general configuration of the MEFV curve, were determined in 119 steroid-naïve individuals with atopic asthma aged 8 to 16 years, and in 92 age-matched healthy controls. Receiver operating characteristic (ROC) curve analyses were performed to determine the cutoff points of FeNO and angle β that provided the best combination of sensitivity and specificity for asthma detection.ResultsAsthmatic patients had a significantly smaller angle β and higher FeNO compared with healthy controls (both, P<0.001). For asthma detection, the best cutoff values of angle β and FeNO were observed at 189.3° and 22 parts per billion, respectively. The area under the ROC curve for the combination of angle β and FeNO improved to 0.91 (95% confidence interval [CI], 0.87–0.95) from 0.80 (95% CI, 0.75–0.86; P<0.001) for angle β alone and 0.86 (95% CI, 0.82–0.91; P=0.002) for FeNO alone. In addition, the combination enhanced sensitivity with no significant decrease in specificity.ConclusionThese data suggest that the combined use of the curvilinearity of the MEFV curve and FeNO is a useful tool to differentiate between children with and without atopic asthma.

Exhaled nitric oxide helps discriminating asthmatic children with and without positive specific IgE to aeroallergens.

Aeroallergen sensitization may predict higher fractional exhaled nitric oxide (FeNO) levels. We evaluate cut-off values of FeNO in asthmatic children with and without positive specific immunoglobulin E (IgE) to at least one of 5 aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, and cockroach). 564 patients with asthma and allergic rhinitis (AR) aged 5 to 18 years were enrolled into two groups. Sensitized group included 378 children with positive IgE to at least one of 5 inhaled allergens. Non-sensitized group included 186 children. Pulmonary function tests, FeNO, eosinophil counts, and IgE levels were examined. Patients were divided into preschool age (5~6 years old), elementary school children (7~11 years old) and adolescents (12~18 years old). In preschool children, FeNO≥15.5 ppb differentiates between non-sensitized and sensitized groups. (sensitivity 54.3%; specificity 87.5%; positive predictive value (PPV) 86.2%; negative predictive value (NPV) 57.1%; area under receiver operating characteristic curve (AUC) 0.72) Among elementary school children, the cut-off value of FeNO≥19.5 ppb showed sensitivity 66.4%; specificity 85.8%; PPV 90.5%; NPV 55.7%; AUC 0.81. In adolescents, FeNO≥27.5 ppb showed sensitivity 60.2%; specificity 85.4%; PPV 91.2%; NPV 46.1%; AUC 0.76. In asthmatic children, aeroallergen sensitization appears to contribute to higher FeNO levels than those not sensitized. Cut-off values of FeNO which well discriminate asthmatic children with and without aeroallergen sensitization should be chose according to different ages.

A Transcriptome-driven Analysis of Epithelial Brushings and Bronchial Biopsies to Define Asthma Phenotypes in U-BIOPRED.

Asthma is a heterogeneous disease driven by diverse immunologic and inflammatory mechanisms. Using transcriptomic profiling of airway tissues, we sought to define the molecular phenotypes of severe asthma. The transcriptome derived from bronchial biopsies and epithelial brushings of 107 subjects with moderate to severe asthma were annotated by gene set variation analysis using 42 gene signatures relevant to asthma, inflammation, and immune function. Topological data analysis of clinical and histologic data was performed to derive clusters, and the nearest shrunken centroid algorithm was used for signature refinement. Nine gene set variation analysis signatures expressed in bronchial biopsies and airway epithelial brushings distinguished two distinct asthma subtypes associated with high expression of T-helper cell type 2 cytokines and lack of corticosteroid response (group 1 and group 3). Group 1 had the highest submucosal eosinophils, as well as high fractional exhaled nitric oxide levels, exacerbation rates, and oral corticosteroid use, whereas group 3 patients showed the highest levels of sputum eosinophils and had a high body mass index. In contrast, group 2 and group 4 patients had an 86% and 64% probability, respectively, of having noneosinophilic inflammation. Using machine learning tools, we describe an inference scheme using the currently available inflammatory biomarkers sputum eosinophilia and fractional exhaled nitric oxide levels, along with oral corticosteroid use, that could predict the subtypes of gene expression within bronchial biopsies and epithelial cells with good sensitivity and specificity. This analysis demonstrates the usefulness of a transcriptomics-driven approach to phenotyping that segments patients who may benefit the most from specific agents that target T-helper cell type 2-mediated inflammation and/or corticosteroid insensitivity.

Respiratory symptoms and fractional exhaled nitric oxide (FeNO) among students in Penang, Malaysia in relation to signs of dampness at school and fungal DNA in school dust

Few health studies exist on dampness and mould in schools in the tropics. We studied associations between fraction of exhaled nitric oxide (FeNO), respiratory symptoms and airway infections among students and dampness and fungal DNA in schools in Malaysia. A total of 368 randomly selected students from 32 classrooms in 8 secondary schools in Penang, Malaysia, participated (58% participation rate). Information on current respiratory symptoms and the home environment was collected by a standardised questionnaire. FeNO was measured by NIOX MINO (50ml/min). The classrooms were inspected and dust was collected by vacuuming on special filters and was analysed for five fungal DNA sequences by quantitative PCR. Linear mixed models and 3-level multiple logistic regression (school, classroom, student) were applied adjusting for demographic data and the home environment. Totally 10.3% reported doctor's diagnosed asthma, 15.1% current wheeze, 12.4% current asthma, 37.3% daytime breathlessness, 10.2% nocturnal breathlessness, 38.9% airway infections and 15.5% had pollen or furry pet allergy. The geometric mean of FeNO was 19.9ppb and 45% had elevated FeNO (>20ppb). Boys had higher levels of FeNO. Chinese had less daytime breathlessness than Malay (OR=0.30: p<0.001). Indoor carbon dioxide levels were low (380–720ppm). Dampness was observed in 18% of the classrooms and was associated with respiratory infections (OR=3.70; 95% CI 1.14–12.1) and FeNO (p=0.04). Aspergillus versicolor DNA was detected in 67% of the classrooms. Higher numbers of Aspergillus versicolor DNA in classroom dust were associated with wheeze (p=0.006), current asthma (p=0.002), respiratory infections (p=0.005) and elevated FeNO levels (p=0.02). In conclusion, respiratory symptoms were common among the students and the high FeNO levels indicate ongoing airway inflammation. Building dampness and the mould Aspergillus versicolor in schools in Malaysia can be risk factors for impaired respiratory health among the students.

Diagnostic utility of fractional exhaled nitric oxide in prolonged and chronic cough according to atopic status

BackgroundCough-variant asthma (CVA) and cough-predominant asthma (CPA) are the major causes of persistent cough in Japan. The utility of fractional exhaled nitric oxide (FeNO) measurement in the differential diagnosis of persistent cough has been reported, but the influence of atopic status, which is associated with higher FeNO levels, on the diagnostic utility of FeNO has been unknown. MethodsWe retrospectively analyzed 105 non-smoking patients with prolonged and chronic cough that were not treated with corticosteroids and anti-leukotrienes. ResultsCPA was diagnosed in 37 patients, CVA in 40, and non-asthmatic cough (NAC) in 28. FeNO levels were significantly higher in the CPA [35.8 (7.0–317.9) ppb] and CVA [24.9 (3.1–156.0) ppb] groups than in the NAC group [18.2 (6.9–49.0) ppb] (p < 0.01 by Kruskal–Wallis test). The optimal cut-off for distinguishing asthmatic cough (AC; CPA and CVA) from NAC was 29.2 ppb [area under the curve (AUC) 0.74, p < 0.01]. Ninety-one percent of subjects with FeNO levels ≥29.2 ppb had AC. Meanwhile, 40% of AC patients had FeNO levels <29.2 ppb. Stratified cut-off levels were 31.1 ppb (AUC 0.83) in atopic subjects vs. 19.9 ppb (AUC 0.65) in non-atopic subjects (p = 0.03 for AUC). ConclusionsAlthough high FeNO levels suggested the existence of AC, lower FeNO levels had limited diagnostic significance. Atopic status affects the utility of FeNO levels in the differential diagnosis of prolonged and chronic cough.

Aging with higher fractional exhaled nitric oxide levels are associated with increased urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine concentrations in elder females.

Indoor air pollutants from environmental tobacco smoke and cooking fume can induce oxidative stress and inflammatory response, which generate oxidatively damaged DNA in human body. Among 2224 adults, levels of FENO and urinary 8-oxodG were measured using a nano coulomb nitric oxide analyzer and a high performance liquid chromatography system with electrochemical detector, respectively. Association between aging with higher FENO levels and urinary 8-oxodG levels were analyzed using multiple linear regression analysis. Nonsmoking women aged 64years and over, with higher FENO (≥ 25 part per billion) and self-catering but without passive smoking had a higher risk of increased urinary 8-oxodG (△% of urinary 8-oxodG: 81.3%, 95% CI: 27.4-158.0%) levels, particularly these elderly women with using liquefied petroleum gas for cooking, had a higher risk for increased urinary 8-oxodG levels (△% of urinary 8-oxodG: 100.2%, 95% CI: 95% CI: 35.3-196.3%), compared with those aged less than 64years, with lower FENO (< 25 part per billion). Cooking activity aggravated aging-related the aging-induced in urinary 8-oxodG excretion among nonsmoking women aged 64years and over but without passive smoking.

Measurement of levels of fractional exhaled nitric oxide in patients with pulmonary tuberculosis.

The role of fractional exhaled nitric oxide (FeNO) in the diagnosis and treatment of pulmonary tuberculosis (PTB) is uncertain. To examine the value of FeNO as a biomarker for PTB. Baseline FeNO levels were compared in 69 PTB patients and 118 healthy controls. The correlation between baseline FeNO levels and clinical variables of tuberculosis were studied. FeNO levels were checked twice in the PTB group, at diagnosis and after 2 months of anti-tuberculosis medication, and factors affecting changes in FeNO levels after treatment were analysed. FeNO levels were not significantly different in the PTB group and controls (mean ± standard deviation 27.7 ± 17.6 parts per billion [ppb] vs. 27.0 ± 10.8 ppb, P = 0.531). In a multivariate regression analysis, no variable was shown to affect FeNO levels at diagnosis. FeNO levels did not significantly change after 2 months of treatment (26.8 ± 18.3 ppb vs. 24.0 ± 10.7 ppb, P = 0.257). Only PTB with a high FeNO level (>25 ppb) was related to a decline in FeNO levels after 2 months of treatment. FeNO levels do not appear to be affected in PTB patients.