Factors that influence exhaled nitric oxide in Italian schoolchildren

Markers of eosinophilic airway inflammation in patients with asthma and allergic rhinitis

Background: Measurement of airway inflammation is an important step to determine phenotype of asthma and allergic rhinitis (AR). Objective: To assess the level of nitric oxide in exhaled air (FeNO), nasal fraction of nitric oxide (nasal NO), their relationship with clinical control and blood eosinophils in patients with steroid-naive mild and moderate asthma and AR. Methods: One hundred forty-seven patients (65 men), ages 26-49.5 years (mean age, 32 years) with AR (n = 81) or AR and concomitant asthma (n = 46) and 20 healthy subjects were included in a single-center cohort study. All the patients underwent spirometry with reversibility test. Control of asthma and AR was assessed by using the Asthma Control Questionnaire and the visual analog scale, respectively. Levels of FeNO and nasal NO were measured by chemiluminescent analyzer, peripheral blood eosinophils were counted by automatic analyzer. Results: The FeNO level was significantly elevated in the patients with asthma and concomitant AR compared with the healthy subjects and was associated with control of both asthma and AR. There was no correlation between nasal NO and control of AR. Receiver operating characteristic analysis revealed that the level of eosinophils of 150 cells/μL may be a cutoff for lower airway eosinophilic inflammation. Blood eosinophils count was unable to distinguish eosinophilic and non-eosinophilic upper airway inflammation. Conclusion: We confirm that FeNO but not nasal NO is a marker of eosinophilic airway inflammation in patients with mild-moderate steroid-naive AR and concomitant asthma. A blood eosinophil level of ≥150 cells/µL may be a simple marker of eosinophilic airway inflammation in patients with asthma. However, its low specificity requires repeated measurements and use in combination with other biomarkers.

Fractional Exhaled Nitric Oxide (FENO) in the management of asthma: a position paper of the Italian Respiratory Society (SIP/IRS) and Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC)

Asthma prevalence in Italy is on the rise and is estimated to be over 6% of the general population. The diagnosis of asthma can be challenging and elusive, especially in children and the last two decades has brought evidences that asthma is not a single disease but consists of various phenotypes. Symptoms can be underestimated by the patient or underreported to the clinician and physical signs can be scanty. Usual objective measures, like spirometry, are necessary but sometimes not significant. Despite proper treatment, asthma can be a very severe condition (even leading to death), however new drugs have recently become available which can be very effective in its control. Since asthma is currently thought to be caused by inflammation, a direct measure of the latter can be of paramount importance. For this purpose, the measurement of Fractional Exhaled Nitric Oxide (FE_NO) has been used since the early years of the current century as a non-invasive, easy-to-assess tool useful for diagnosing and managing asthma. This SIP-IRS/SIAAIC Position Paper is a narrative review which summarizes the evidence behind the usefulness of FE_NO in the diagnosis, management and phenotypization of asthma.

Association of pediatric obesity and asthma, pulmonary physiology, metabolic dysregulation, and atopy; and the role of weight management

Introduction: Obesity affects about 40% of US adults and 18% of children. Its impact on the pulmonary system is best described for asthma. Areas covered: We reviewed the literature on PubMed and Google Scholar databases and summarize the effect of obesity, its associated metabolic dysregulation and altered systemic immune responses, and that of weight gain and loss on pulmonary mechanics, asthma inception, and disease burden. We include a distinct approach for diagnosing and managing the disease, including pulmonary function deficits inherent to obesity-related asthma, in light of its poor response to current asthma medications. Expert opinion: Given the projected increase in obesity, obesity-related asthma needs to be addressed now. Research on the contribution of metabolic abnormalities and systemic immune responses, intricately linked with truncal adiposity, and that of lack of atopy, to asthma disease burden, and pulmonary function deficits among obese children is fairly consistent. Since current asthma medications are more effective for atopic asthma, investigation for atopy will guide management by distinguishing asthma responsive to current medications from the non-responsive disease. Future research is needed to elucidate mechanisms by which obesity-mediated metabolic abnormalities and immune responses cause medication non-responsive asthma, which will inform repurposing of medications and drug discovery.

Exhaled nitric oxide can't replace the methacholine challenge in suspected pediatric asthma

BACKGROUND

In adults, measurement of F_ENO has been recently suggested as a substitute for the methacholine challenge test (MCT) for diagnosis of asthma. This study aimed to evaluate whether FeNO is a substitute for MCH also in children with suspicious asthma.

METHODS

During a single visit steroid naive children (5-17 years) with suspicious asthma underwent skin prick test (SPT), F_ENO measurement and spirometry prior and during MCT (one concentration procedure). Results of the SPT (atopy/non-atopy) and MCT (asthma/non-asthma) were used for categorization. ROC analysis in atopy non-atopy subgroups yielded sensitivity, specificity, positive and negative predictive value (PPV and NPV) for F_ENO.

RESULTS

The SPT revealed atopy in 134 out of 222 children (age 9.7 ± 3.2 years) investigated and asthma was diagnosed in 114 (77/37 atopy/non-atopy) patients. F_ENO values in patients with atopic asthma were significantly higher compared to those with either non-atopic asthma or atopia without asthma (18 ppb (5-89) vs 7 ppb (5-36); p < 0.001; 18 ppb (5-89) vs 11 ppb (5-98); p < 0.05). Sensitivity and specificity of F_ENO for diagnosing atopic asthma (F_ENO≥15.5 ppb; AUC = 0.635, p < 0.01) were 61.1% and 64.9% and non-atopic asthma (F_ENO≥ 6.5 ppb; AUC = 0.445, p = 0.382) 54.1% and 39.2%, respectively. The PPV/NPV for F_ENO were 0.70/0.55 in atopy and 0.39/0.54 in non-atopy patients, respectively.

CONCLUSION

In children, F_ENO is not appropriate to substitute for the MCT. However, in patients with a negative SPT a F_ENO in the normal range makes the presence of atopic asthma unlikely.

FeNO level and allergy status among school children in Terengganu, Malaysia

Background: Almost one third of the world population suffers from allergic conditions. Respiratory symptoms are common in Malaysian children but there are few studies on fractional exhaled nitric oxide (FeNO), inclusive of field clinical test for asthma among children in Malaysia. The aim was to provide insight on factors related to level of FeNO among students in Terengganu, Malaysia.Methods: In total, 487 randomly selected students from eight secondary schools participated (13-14 years old). A Standardized questionnaire was used to obtained information on doctors' diagnosed asthma, current asthma and respiratory symptoms. FeNO measurement and skin prick test (SPT to common allergen) were conducted.Results: The geometric mean FeNO was 16.7 ppb. Totally, 38.4% of students had elevated FeNO level (>20 ppb) and 40.3% had had positive SPT to house dust mites allergens (HDM), Dermatophagoides pteronyssinus (Der p 1), Dermatophagoides farinae (Der f 1) or Felis domisticus (cat). Male gender, height, parental history of allergy, self-reported allergy, and atopy were associated with FeNO. In particular, a combination of sensitization to HDM or cat and elevated FeNO were associated with doctor-diagnosed asthma and self-reported allergy to food, pollen and cat.Conclusion: Asthma, respiratory symptoms and sensitization to HDM and cat are common among students and presence of elevated FeNO levels indicate ongoing airway inflammation.

Fractional Exhaled Nitric Oxide Values in Indigenous Australians 3 to 16 Years of Age

BACKGROUND

Fractional exhaled nitric oxide (Feno) levels can identify eosinophilic asthma phenotypes. We aimed to determine Feno values of healthy Aboriginal and/or Torres Strait Islander (Indigenous) Australians, differences between these Indigenous ethnic groups, and appropriateness of published cutoff values.

METHODS

We measured Feno levels in 1,036 Indigenous Australians (3-16 years of age). Participants were classified into healthy (ie, no asthma or atopy history) or asthmatic and/or atopic groups.

RESULTS

Median Feno values and distribution did not differ between Indigenous ethnicities. For healthy participants < 12 years of age (n = 390), 7.2% of our cohort fell into the inflammatory zone of the American Thoracic Society (ATS), National Institute for Health and Care Excellence (NICE), and British Thoracic Society (BTS)/Scottish Intercollegiate Guidelines Network (SIGN) guidelines (cutoff 35 parts per billion [ppb]), but only 3.8% fell into this category when using the Global Initiative for Asthma (GINA) guidelines (50 ppb). Similarly, when using the NICE and BTS/SIGN guidelines (40 ppb) for participants 12 to 16 years of age (n = 213), more healthy participants fell into the inflammatory zone compared with the ATS and GINA guidelines (50 ppb) (9.9% vs 4.7%, respectively).

CONCLUSIONS

Feno values for healthy Indigenous Australians children (3-16 years of age) are likely higher than published white-based values. The GINA recommended cutoff value (> 50 ppb) appears the most appropriate for identifying healthy Indigenous children but requires confirmation from a larger study.

Sensitization to dust mite defines different phenotypes of asthma: A multicenter study

BACKGROUND

Indoor allergens are risk factors for asthma: Thus, the characterization of indoor air quality is important for studying environment-health relationships in children. In particular, Dermatophagoides pteronyssinus is the dominant allergen for asthma. We cross-sectionally investigated the relationships among respiratory symptoms and function, airway inflammation, allergen sensitization, and indoor allergen concentration.

METHODS

One hundred and thirty-two children aging 10-14 years and living in a Southern Mediterranean area were evaluated by parental questionnaires. Spirometry, exhaled nitric oxide (FeNO), skin prick tests, total, and specific serum IgE analyses were performed along with the evaluation of home dust samples for the content in Der p 1 allergen. Three clusters were created on the basis of the presence/absence of wheeze in the last 12 months (Wh12m) and Der p 1-specific IgE level.

RESULTS

Cluster 1 (Wh12m+/high Der p 1 IgE) presented higher FeNO and poorer pulmonary function (lower FEV₁ and FEF_25%-75% ), while its symptom score was not different from Cluster 2 (Wh12m+/low Der p 1 IgE). Cluster 3 (Wh12m-/low IgE) showed the lowest FeNO values and pulmonary function similar to Cluster 2. Within Cluster 1, both Der p 1-specific IgE and FeNO were positively correlated with dust Der p 1.

CONCLUSIONS

Similar asthma phenotypes may occur in children despite differences in their atopic state. In atopic children, sensitizing allergens in the indoor environment may increase airway inflammation worsening pulmonary function. Moreover, environmental exposures may contribute to the development of asthma-like symptoms also in the absence of atopic sensitization, thus contributing to asthma overdiagnosis.

Global Lung Function Initiative 2012 reference values for spirometry in South Italian children

RATIONALE

Despite the widespread use of the Global Lung Function Initiative (GLI) 2012 reference values, there is still the need of testing their applicability in local areas.

OBJECTIVES

The aims of this study are to evaluate applicability of GLI reference equations in a large population-based sample of normal schoolchildren from Sicily, and to compare GLI and previous prediction equations in terms of spirometry test interpretation.

METHODS

GLI equations were evaluated in 1243 normal schoolchildren, 49% males, aged 7-16 years, height 116-187 cm. Normality assumptions for the GLI z-scores (FEV₁, FVC, FEV₁/FVC) were tested, and bootstrap confidence intervals for the mean (0 expected) and the variance (1 expected) were derived. GLI and other reference equations were compared in terms of probabilities to fall below the lower limit of normal (LLN).

RESULTS

The GLI z-score normality assumption held for males but not for females (p < 0.001). According to the mean z-score, predicted values were: slightly underestimated for FEV₁ (0.15 in males, 0.07 in females); overestimated for FVC (-0.27 in males, -0.32 in females); highly underestimated for FEV₁/FVC (0.75 in males, 0.81 in females). Variability was correctly estimated. The probability of FEV₁<LLN correctly approached 0.05 when using GLI, Hankinson and Quanjer equations. Wang equations yielded correct probabilities of abnormal FVC; Pistelli equations yielded correct probabilities of abnormal FEV₁/FVC for females.

CONCLUSIONS

GLI 2012 references underestimate FEV₁/FVC predicted values in a sample of normal South Italian children. Physicians interpreting spirometry should be aware to test reference values prior to their use in a local area.

Exhaled NO: Determinants and Clinical Application in Children With Allergic Airway Disease

Nitric oxide (NO) is endogenously released in the airways, and the fractional concentration of NO in exhaled breath (FeNO) is now recognized as a surrogate marker of eosinophilic airway inflammation that can be measured using a noninvasive technique suitable for young children. Although FeNO levels are affected by several factors, the most important clinical determinants of increased FeNO levels are atopy, asthma, and allergic rhinitis. In addition, air pollution is an environmental determinant of FeNO that may contribute to the high prevalence of allergic disease. In this review, we discuss the mechanism for airway NO production, methods for measuring FeNO, and determinants of FeNO in children, including host and environmental factors such as air pollution. We also discuss the clinical utility of FeNO in children with asthma and allergic rhinitis and further useful directions using FeNO measurement.

An elevated body mass index increases lung volume but reduces airflow in Italian schoolchildren

Background

Asthma and obesity are important and growing health issues worldwide. Obesity is considered a risk factor for asthma, due to the induction of changes in airway mechanics and altered airway inflammation.

Methods

We cross-sectionally investigated the effect of increased weight on pulmonary function in a large population sample of healthy children, aged 10–17 yrs living in Palermo, Italy. Explanatory effect of weight on lung function variables were evaluated by multiple linear regression models, taking into account height, gender, and age-class.

Results

Among the 2,393 subjects, FVC and FEV₁ were positively correlated to weight. Multiple regression models showed that the weight beta coefficient for FEV₁ was significantly lower with respect to that for FVC (0.005 and 0.009 l/kg, respectively), indicating a different magnitude in explanatory effect of weight on FVC and FEV₁. Both FEV₁/FVC and FEF_25–75%/FVC ratios were negatively correlated to weight, while FEF_25–75% was not significantly correlated. Similar results were obtained also when 807 symptomatic subjects were introduced in the model through a sensitivity analysis.

Conclusion

In healthy children, the disproportionate increase of FEV₁ and FVC with weight produces airflow decrease and consequently apparent poorer lung function independently from respiratory disease status.

The value of FeNO measurement in childhood asthma: uncertainties and perspectives

Asthma is considered an heterogeneous disease, requiring multiple biomarkers for diagnosis and management. Fractional exhaled nitric oxide in exhaled breath (FeNO) was the first useful non-invasive marker of airway inflammation in asthma and still is the most widely used. The non-invasive nature and the relatively easy use of FeNO technique make it an interesting tool to monitor airway inflammation and rationalize corticosteroid therapy in asthmatic patients, together with the traditional clinical tools (history, physical examination and lung function tests), even if some controversies have been published regarding the use of FeNO to support the management of asthma in children. The problem of multiple confounding factors and overlap between healthy and asthmatic populations preclude the routine application of FeNO reference values in clinical practice and suggest that it would be better to consider an individual "best", taking into account the context in which the measurement is obtained and the clinical history of the patient. Besides, there is still disagreement about the role of FeNO as a marker of asthma control, due to the complexity of balance among the different items involved in its determination and the lack of homogeneity in the population groups studied in the few studies conducted so far. Heterogeneity of problematic severe asthma greatly limits utility of FeNO alone as a biomarker of inflammation to optimize the disease management on an individual basis. None of the studies conducted so far demonstrated that the use of FeNO was better than current asthma guidelines in controlling asthma exacerbations. In summary, there is a large variation in FeNO levels between individuals, which may reflect the natural heterogeneity in baseline epithelial nitric oxide synthase activity and/or the contribution of other noneosinophilic factors to epithelial nitric oxide synthase activity. FeNO is a promising biomarker, but at present some limits are highlighted. We would recommend that further research can be carried out by organizing studies aimed to obtain reliable reference values of FeNO and in order to better interpret FeNO measurements in clinical settings, taking also into account the influence of genetic and environmental factors.

Role of exhaled nitric oxide as a predictor of atopy

BACKGROUND

The fractional exhaled nitric oxide (FeNO) is a quantitative, noninvasive and safe measure of airways inflammation that may complement the assessment of asthma. Elevations of FeNO have recently been found to correlate with allergic sensitization. Therefore, FeNO may be a useful predictor of atopy in the general population. We sought to determine the diagnostic accuracy of FeNO in predicting atopy in a population-based study.

METHODS

We conducted a cross-sectional study in an age- and sex- stratified random sample of 13 to 15 year-olds in two communities in Peru. We asked participants about asthma symptoms, environmental exposures and sociodemographics, and underwent spirometry, assessment of FeNO and an allergy skin test. We used multivariable logistic regression to model the odds of atopy as a function of FeNO, and calculated area-under-the-curves (AUC) to determine the diagnostic accuracy of FeNO as a predictor of atopy.

RESULTS

Of 1441 recruited participants, 1119 (83%) completed all evaluations. Mean FeNO was 17.6 ppb (SD=0.6) in atopics and 11.6 ppb (SD=0.8) in non-atopics (p<0.001). In multivariable analyses, a FeNO>20 ppb was associated with an increase in the odds of atopy in non-asthmatics (OR=5.3, 95% CI 3.3 to 8.5) and asthmatics (OR=16.2, 95% CI 3.4 to 77.5). A FeNO>20 ppb was the best predictor for atopy with an AUC of 68% (95% CI 64% to 69%). Stratified by asthma, the AUC was 65% (95% CI 61% to 69%) in non-asthmatics and 82% (95% CI 71% to 91%) in asthmatics.

CONCLUSIONS

FeNO had limited accuracy to identify atopy among the general population; however, it may be a useful indicator of atopic phenotype among asthmatics.

A cross-sectional study assessing the relationship between BMI, asthma, atopy, and eNO among schoolchildren

BACKGROUND

Increased body weight may influence airway inflammatory mechanisms.

OBJECTIVE

To assess whether overweight-obesity (OW-O), evaluated as increased body mass index, is associated either with exhaled nitric oxide (eNO), a marker of airway inflammation, or with allergic sensitization in a large sample of children and adolescents.

METHODS

A cross-sectional, epidemiological study was performed on a population sample of schoolchildren evaluating 708 subjects (age 10-16 years; BMI 13-39 kg/m(2)) by respiratory health questionnaire, skin prick tests, spirometry, and eNO measure.

RESULTS

Prevalence rates were: OW-O 16.4%, asthma ever (A) 11.9%, and rhinoconjunctivitis (RC) 14.8%. Asthma ever and allergic sensitization were significantly more frequent among OW-O (21.0 and 51.6%) than in non-OW-O (10.2 and 37.0%, respectively). The forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) ratio was not significantly different between OW-O and non-OW-O. Exhaled NO (median and interquartile range) was 15.3 (11.2-23.1) ppb in the overall sample, 20.3 (12.9-35.8) ppb among allergic subjects, and 13.9 (10.6-18.3) ppb among nonallergic subjects (P<.0001). No significant difference between OW-O and non OW-O subjects was found in eNO levels. Similarly, OW-O subjects with A or RC did not show significantly higher eNO levels than non-OW-O. In a logistic regression model, presence of allergic sensitization, A, and RC, and not OW-O, were significant predictors of increased eNO.

CONCLUSIONS

In children, OW-O was not associated with increased eNO levels, but it was an independent risk factor for asthma and allergic sensitization.

Environmental effects on fractional exhaled nitric oxide in allergic children

Fractional exhaled nitric oxide (FeNO) is a non-invasive marker of airway inflammation in asthma and respiratory allergy. Environmental factors, especially indoor and outdoor air quality, may play an important role in triggering acute exacerbations of respiratory symptoms. The authors have reviewed the literature reporting effects of outdoor and indoor pollutants on FeNO in children. Although the findings are not consistent, urban and industrial pollution-mainly particles (PM(2.5) and PM(10)), nitrogen dioxide (NO(2)), and sulfur dioxide (SO(2))-as well as formaldehyde and electric baseboard heating have been shown to increase FeNO, whilst ozone (O(3)) tends to decrease it. Among children exposed to Environmental Tobacco Smoke (ETS) with a genetic polymorphisms in nitric oxide synthase genes (NOS), a higher nicotine exposure was associated with lower FeNO levels. Finally, although more studies are needed in order to better investigate the effect of gene and environment interactions which may affect the interpretation of FeNO values in the management of children with asthma, clinicians are recommended to consider environmental exposures when taking medical histories for asthma and respiratory allergy. Further research is also needed to assess the effects of remedial interventions aimed at reducing/abating environmental exposures in asthmatic/allergic patients.

Effects of atopy and rhinitis on exhaled nitric oxide values - a systematic review

Background

Atopy and rhinitis are among the factors affecting exhaled nitric oxide (FeNO) values and may contribute to difficulties in the clinical interpretation of FeNO measurements. However, data assessing their effects on FeNO values had never been summarized. This review aims to evaluate the effect of atopy and rhinitis in FeNO values in otherwise healthy individuals.

Methods

A systematic review was performed in Pubmed, Scopus and ISI Web of Knowledge. A two-step selection process was completed, and from 2357 references 19 were included. The inclusion criteria were: participants without known diseases other than rhinitis; atopy assessement by SPT or Specific IgE; and FeNO measurements according to ATS/ERS recommendations.

Results

The 8 articles measuring FeNO in children showed higher values in both allergic rhinitis and atopic children when compared with healthy children. The 11 articles performed in adults observed higher FeNO in AR patients comparatively with either healthy or atopic individuals. However, adult healthy and atopic individuals had similar FeNO values.

Conclusions

FeNO values are higher in individuals with rhinitis and/or atopy without other health problems. These effects are small, seem to be independent and should be further studied using multivariate models. The effect of atopy was observed only in children. The combined effect of atopy and rhinitis produced higher FeNO values in adults. These results support that both atopy and rhinitis should be considered when interpreting or when defining FeNO reference values.

Novel perspectives in the detection of oral and nasal oxidative stress and inflammation in pediatric united airway diseases

United airway disease (UAD) concept proposed that asthma and rhinitis are both different clinical manifestation of a single inflammatory process. The aim of this study is to assess in upper and lower airways the level of inflammation and oxidative stress and to investigate the relationship between biomarkers in persistent allergic rhinitis (PER) and in concomitant asthma with PER. By a crosssectional study we measured oral and nasal (FENO) and oral and nasal EBC 8-isoprostane, LTB4 and PGE2 in children with PER (n=14) and with PER and concomitant intermittent asthma (IA; n=25), mild persistent asthma (mA; n=28), moderate persistent asthma (MA; n=13) and in Healthy Controls (HCs; n=13). Oral and nasal FENO concentrations were increased in children with PER, IA, mA and MA when compared with HCs. Nasal 8-isoprostane was higher in EBC of children with PER and asthma than in HCs. Oral and nasal LTB4 were higher in EBC of children with PER and mA than in HCs. Oral and nasal PGE2 concentrations were higher in EBC of children with PER than in HCs. Positive correlations between oral and nasal biomarkers were found in IA for LTB4 and PGE2, in mA for FENO, 8-isoprostane, LTB4 and PGE2, and in MA for PGE2. No correlations were observed in children with PER and HCs. Our results suggest that non-invasive markers of inflammation and oxidative stress might be useful to study the relationships between oral and nasal compartments in allergic children with PER and concomitant asthma with the aim of defining the UAD.

Relationship between exhaled nitric oxide and small airway lung function in normal and asthmatic children

BACKGROUND

In children, exhaled nitric oxide (eNO) is usually confounded by factors such as age and height. We evaluated the relationship between eNO and lung function by minimizing the effects of aging and height.

METHODS

In Study 1, the subjects comprised 738 elementary school children and junior high school children (aged 6 to 15 years, 366 males and 372 females). They were divided into two groups according to age (6-10 years and 11-15 years). A height range was determined by a histogram of height in each group. In Study 2, lung function, respiratory resistance and eNO level were measured in age- and height-limited groups.

RESULTS

In Study 1, total of 148 younger children ranging in height from 120 to 130 cm and 180 older children ranging in height from 148 to 158 cm participated in Study 2. The level of eNO among asthmatic children was higher than that of normal children in both the younger and the older groups. The decrease in forced expiratory volume in 1 second (FEV(1)) and other parameters of central airway resistance did not correlate with the eNO level. However, the small airway parameters of MMEF and V(25)/HT in older asthmatic children, and V(25)/HT and R(5)-R(20) in younger asthmatic children inversely correlated with eNO.

CONCLUSIONS

Our data suggest that eNO level inversely correlates with small airway narrowing, and airway inflammation has a significant effect on small airway lung function in asthmatic school children.

Proportional Venn diagram and determinants of allergic respiratory diseases in Italian adolescents

Large variations in prevalence of atopy and allergic diseases are reported worldwide in children, but in epidemiological studies the use of skin prick tests (SPT) and spirometry along with questionnaires is not common in the Mediterranean Area. The present work was aimed at evaluating the prevalence of current asthma (CA), rhinoconjunctivitis (RC), and eczema (E), with atopy and respiratory function, and the role of risk factors for allergic respiratory diseases. A total of 2150 Italian schoolchildren were cross-sectionally investigated through respiratory questionnaire, SPT, and spirometry. A proportional Venn diagram quantified the distribution of CA, RC, and E, stratifying for allergic sensitization to show differences in prevalence of allergic diseases among subjects with and without positive SPT. CA prevalence was 4.2%, RC 17.9%, and E 5.3%. CA and RC increased, while E decreased, with respect to previous local studies. Allergic sensitization prevalence (evaluated as positive response to at least one SPT) was 39.2%. A double Venn diagram identified 15 categories. Atopic CA was threefold more frequent than non-atopic CA. Atopic vs non-atopic RC and E were 9.6% vs 10.3% and 2.0% vs 3.3%, respectively. Atopic vs non-atopic RC associated with CA were 1.6% vs 0.5%; the same figures for RC associated with E were 0.8% vs 1.3%. Asymptomatic atopic subjects were 27.0%. Atopy, RC, parental asthma, and environmental risk factors were associated with CA. Atopy and environmental factors were risk factors also for RC. Asthma and traffic exposure were linked to reduced lung function. Respiratory allergic diseases are still increasing and largely concomitant in Italian adolescents. Atopy is more important for CA than RC. Avoiding exposures to measured environmental risk factors would prevent 41% of current asthma and 34% of rhinoconjunctivitis.

Air pollution and increased levels of fractional exhaled nitric oxide in children with no history of airway damage

Air pollution is associated with a wide range of adverse respiratory events. In order to study the mechanism associated with these effects, the relationships between fractional exhaled nitric oxide (FeNO), a potential marker of airway inflammation, and exposure to air pollution were examined in schoolchildren. FeNO was measured in 104 children (34 asthmatics and 70 non-asthmatics) drawn from the general population simultaneously with air pollution assessments (fine particles with an aerodiameter under 2.5 microm, nitrogen dioxide, acetaldehyde, and formaldehyde, with pumps and passive samplers) in schoolyards and classrooms. Asthmatics exhaled more FeNO than non-asthmatics. FeNO levels were significantly elevated in both asthmatic and non-asthmatic children exposed to high concentrations of formaldehyde, acetaldehyde, and PM(2.5). Differences between high versus low exposure in non-asthmatics resulted in an FeNO increase ranging from 45% for indoor acetaldehyde to 62% for indoor PM(2.5). Stronger associations were found in non-asthmatic children who were atopic, suggesting that atopic children may be more sensitive to air pollution than non-atopic children. Exposure to air pollution may lead to airway inflammation, as measured by FeNO, in schoolchildren. These associations occur even in children with no history of airway damage and seem to be enhanced in atopic subjects.

Exhaled nitric oxide in diagnosis and management of respiratory diseases

The analysis of biomarkers in exhaled breath constituents has recently become of great interest in the diagnosis, treatment and monitoring of many respiratory conditions. Of particular interest is the measurement of fractional exhaled nitric oxide (FENO) in breath. Its measurement is noninvasive, easy and reproducible. The technique has recently been standardized by both American Thoracic Society and European Respiratory Society. The availability of cheap, portable and reliable equipment has made the assay possible in clinics by general physicians and, in the near future, at home by patients. The concentration of exhaled nitric oxide is markedly elevated in bronchial asthma and is positively related to the degree of esinophilic inflammation. Its measurement can be used in the diagnosis of bronchial asthma and titration of dose of steroids as well as to identify steroid responsive patients in chronic obstructive pulmonary disease. In primary ciliary dyskinesia, nasal NO is diagnostically low and of considerable value in diagnosis. Among lung transplant recipients, FENO can be of great value in the early detection of infection, bronchioloitis obliterans syndrome and rejection. This review discusses the biology, factors affecting measurement, and clinical application of FENO in the diagnosis and management of respiratory diseases.