Oxide In Children Research Articles

Forkhead box protein 3 (FOXP3) hypermethylation is associated with diesel exhaust exposure and risk for childhood asthma

Kelly J. Brunst, Ph.D.1,2,†, Yuet-Kin Leung, Ph.D.2,3, Patrick H. Ryan, Ph.D.1,2,4, Gurjit K. Khurana Hershey, M.D., Ph.D.5, Linda Levin, Ph.D.1,2, Hong Ji, Ph.D.5, Grace K. LeMasters, Ph.D.1, and Shuk-Mei Ho, Ph.D.2,3,6 1Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, 3223 Eden Avenue, Kettering Building, Cincinnati, OH 2Center for Environmental Genetics, University of Cincinnati College of Medicine, 3223 Eden Avenue, Kettering Building, Cincinnati, OH 3Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, 3223 Eden Avenue, Kettering Building, Cincinnati, OH 4Division of Biostatistics and Epidemiology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, MLC 7037, Cincinnati, OH 5Division of Asthma Research, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, MLC 7037, Cincinnati, OH 6Cincinnati Veteran Affairs Medical Center, Merit Scholar, 3200 Vine Street, Cincinnati, OH

Usefulness of impulse oscillometry and fractional exhaled nitric oxide in children with Eosinophilic bronchitis

Eosinophilic bronchitis (EB) is a common cause of chronic cough. Although EB shares many immunopathologic features with asthma, it does not show airway hyperresponsiveness or reversible airway obstruction by spirometry. Compared to healthy children without pulmonary disease, we hypothesized that EB patients would demonstrate abnormal pulmonary function and inflammation with impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO), which are more sensitive tests of these parameters than spirometry. A total of 232 children with asthma, 109 with EB, and 115 control subjects were enrolled. We compared pulmonary function parameters and FeNO levels among the three groups. Additionally, we designated a screening cutoff value of FeNO combined with IOS parameters to distinguish EB from the control group, and identify which children with EB have more asthmatic characteristics. By IOS, the bronchodilator response of the EB and asthma groups increased significantly compared to controls for both reactance at 5 Hz (Δ X5) and reactance area (Δ AX) (P < 0.0001). Cutoff values to distinguish EB from controls were a Δ X5 of -20% (sensitivity, 77.5%; specificity, 49.6%), and Δ AX of -30% (sensitivity, 75.0%; specificity, 46.0%), when the FeNO is 20 ppb. Reversible airway obstruction in IOS and elevated FeNO levels can be detected in children with EB. This would support that EB in children shows airway characteristics similar to those of asthma, and that a continuum exists between asthma and EB.

Domestic airborne black carbon and exhaled nitric oxide in children in NYC

Differential exposure to combustion by-products and allergens may partially explain the marked disparity in asthma prevalence (3-18%) among New York City neighborhoods. Subclinical changes in airway inflammation can be measured by fractional exhaled nitric oxide (FeNO). FeNO could be used to test independent effects of these environmental exposures on airway inflammation. Seven- and eight-year-old children from neighborhoods with lower (range 3-9%, n=119) and higher (range 11-18%, n=121) asthma prevalence participated in an asthma case-control study. During home visits, FeNO was measured, and samples of bed dust (allergens) and air (black carbon; BC) were collected. Neighborhood built-environment characteristics were assessed for the 500 m surrounding participants' homes. Airborne BC concentrations in homes correlated with neighborhood asthma prevalence (P<0.001) and neighborhood densities of truck routes (P<0.001) and buildings burning residual oil (P<0.001). FeNO concentrations were higher among asthmatics with than in those without frequent wheeze (≥4 times/year) (P=0.002). FeNO concentrations correlated with domestic BC among children without seroatopy (P=0.012) and with dust mite allergen among children with seroatopy (P=0.020). The association between airborne BC in homes and both neighborhood asthma prevalence and FeNO suggest that further public health interventions on truck emissions standards and residual oil use are warranted.

The use of 50% nitrous oxide improves successful intravenous access in obese and growth-limited children in an outpatient setting

Commentary on: Ekbom K, Kalman S, Jakobsson J, et al. Efficient intravenous access without distress: a double-blind randomized study of midazolam and nitrous oxide in children and adolescents. Arch Pediatr...

It’s time to rethink mite allergen avoidance

The role of allergen exposure in the etiology of allergic sensitization and asthma is complex. Advice on strategies to avoid domestic allergens remains contentious because trials of interventions aimed to prevent asthma or reduce symptoms have often failed to demonstrate benefits. Asthma management guidelines differ widely in their recommendations, while Web-based information often claims benefits associated with products. In this rostrum we argue that although many factors have a role in both the etiology and the exacerbation of asthma, allergen exposure probably remains an important contributor to the manifestations of the disease. Currently, there is no evidence-based framework for effective domestic allergen avoidance interventions to reduce chronic aeroallergen exposure. The development of an effective approach to allergen avoidance requires a better understanding of (a) the physical nature of chronic aeroallergen exposure and methods for measuring and reducing this, (b) the interaction between allergen exposure and innate immune modulators at different disease stages, and (c) markers enabling the identification of individuals who would benefit from this. The strategic risk of overemphasizing other novel mechanisms and approaches to asthma management is that we will prematurely abandon and fail to improve an existing approach that could have a significant impact on the development, progression, and symptoms of the disease.

High‐frequency oscillatory ventilation associated with inhaled nitric oxide compared to pressure‐controlled assist/control ventilation and inhaled nitric oxide in children: Randomized, non‐blinded, crossover study

To compare the acute oxygenation effects of high-frequency oscillatory ventilation (HFOV) plus inhaled nitric oxide (iNO) with pressure-controlled assist/control ventilation (PCACV) plus iNO in acute hypoxemic respiratory failure (AHRF) children. Children with AHRF, aged between 1 month and 14 years under PCACV with PEEP ≥ 10 cmH(2) O were randomly assigned to PCACV (PCVG, n = 14) or HFOV (HFVG, n = 14) in a crossover design. Oxygenation indexes and hemodynamic variables were recorded at enrollment (Tind), 1 hr after PCACV start (T0) and then every 4 hr (T4h, etc.). PO(2)/FiO(2) significantly increased after 4 hr compared to enrollment in both groups [(PCVG-Tind: 111.95 ± 37 < T4h: 143.88 ± 47.5 mmHg, P < 0.05; HFVG-Tind: 123.76 ± 33 < T4h: 194.61 ± 62.42 mmHg, P < 0.05)] without any statistical differences between groups. At T8h, PO(2)/FiO(2) was greater for HFVG compared with PCVG (HFVG: 227.9 ± 80.7 > PCVG: 171.21 ± 52.9 mmHg, P < 0.05). FiO(2) could be significantly reduced after 4 hr for HFVG (HFVG-T4h: 0.53 ± 0.09 < Tind: 0.64 ± 0.2; P < 0.05) but only after 8 hr for PCVG. Comparing groups at T8h, it was observed that FiO(2) decrease was greater for HFVG (HFVG: 0.47 ± 0.06 < PCVG: 0.58 ± 0.1; P < 0.05). Both ventilatory techniques with iNO improve oxygenation. HFOV causes earlier FiO(2) reduction and increased PO(2)/FiO(2) ratio compared to PCACV at 8 hr. However, at the end of the protocol, there was no significant difference and no clinical improvement derived from the application of both ventilatory strategies with iNO. It is not possible to say what would have happened if a different conventional ventilatory mode and a fully protective ventilatory strategy had been used, given the fact that our study is non-blind, and that a limited number of patients were included in each group.

DNA Methylation in the Arginase–Nitric Oxide Synthase Pathway Is Associated with Exhaled Nitric Oxide in Children with Asthma

Genetic variation in arginase (ARG) and nitric oxide synthase (NOS) has been associated with exhaled nitric oxide (FeNO) levels in children. Little is known about whether epigenetic variation in these genes modulates FeNO. To evaluate whether DNA methylation in ARG and NOS genes is associated with FeNO. A subset of 940 participants in the Children's Health Study were selected for this study. Children were eligible if they had FeNO measurements and buccal cells collected on the same day. CpG loci located in the promoter regions of NOS1, NOS2A, NOS3, ARG1, and ARG2 genes were analyzed. Multiple loci in each gene were evaluated individually and averaged together. DNA methylation was measured using a bisulfite-polymerase chain reaction pyrosequencing assay. Linear regression models were used to investigate the association between DNA methylation and FeNO and whether associations differed by asthma status. DNA methylation in ARG2 was significantly associated with FeNO. A 1% increase in average DNA methylation of ARG2 was associated with a 2.3% decrease in FeNO (95% confidence interval, -4 to -0.6). This association was significantly larger in children with asthma (%diff = -8.7%) than in children with no asthma (%diff = -1.6%; p(int) = 0.01). Differences in FeNO by asthma status were also observed for ARG1 (%diff(asthma) = -4.4%; %diff(non-asthma) = 0.3%; p(int) = 0.02). DNA methylation in NOS genes was not associated with FeNO. DNA methylation in ARG1 and ARG2 is associated with FeNO in children with asthma and suggests a possible role for epigenetic regulation of nitric oxide production.

Measurement of exhaled nitric oxide in children and adolescents

Das endogene Spurengas Stickstoffmonoxid (NO) ist an der Regulation von Immunabwehr, Ventilations-Perfusions-Verhaltnis und Zilienfunktion beteiligt. Fur seine Konzentrationsbestimmung in der Atemluft stehen Standardmethoden, Referenzwerte und Gerate zur Verfugung. Ab dem Vorschulalter gelingt die Online-Messung mit aktiver Ausatmung gegen einen Widerstand, bei jungeren Kindern werden gemischte Atemluftproben vermessen. Umfangreiche padiatrische Daten liegen zur exhalierten Konzentration bei einem Ausatemfluss von 50 ml/s vor. Dieser Parameter reflektiert die bronchiale NO-Freisetzung und ist diagnostisch sensitiv und spezifisch fur atopisches Asthma bronchiale. Sein Stellenwert fur Monitoring und Therapiesteuerung kindlicher Asthmatiker wird kontrovers diskutiert, ein normales Messergebnis schliest bronchiale Hyperreagibilitat und prospektiven Kontrollverlust unter Therapiereduktion relativ zuverlassig aus. Die nasale NO-Messung eignet sich zum Screening auf primare Ziliendyskinesie. Der Beitrag stellt Grundlagen und klinischen Kontext exhalierter NO-Messungen dar und pladiert fur einen rationalen Einsatz in der padiatrischen Pneumologie.

Progress in Pediatric Sedation Research

The practice of pediatric sedation continues to evolve, largely based on data that are produced by researchers in this field. This article reviews notable recent trends in research as reported in peer-reviewed journals, including large prospective database studies that have improved our understanding of the incidence and nature of adverse events in pediatric sedation. Along with this effort has come an attempt to better develop a new lexicon to describe “adverse events” or complications. In addition to these descriptive demographic articles, investigators continue to add to the cumulative experience with new drugs such as dexmedetomidine and older sedatives/analgesics such as ketamine and nitrous oxide in children. Finally, evaluation of the workload and trends in sedation utilization in children have been reported and will be reviewed; and future needs for pediatric sedation research are suggested.

Exhaled Nitric Oxide in Children with Allergic Rhinitis and/or Asthma: A Relationship with Bronchial Hyperreactivity

Background. Nowadays, the measure of the fractional concentration of exhaled nitric oxide (FeNO) enables to assess airway inflammation during an office visit and there is international consensus on this testing methodology. The aim of this study was to evaluate whether FeNO measurement is predictable for bronchial hyperreactivity (BHR) in children with allergic rhinitis, asthma, or both. Methods. Two hundred and eighty children with allergic rhinitis, allergic asthma, or both were evaluated. Bronchial function (FEV1 and FEF25–75), BHR (assessed by methacholine challenge), FeNO, and sensitizations were assessed. Results. Bronchial function, BHR, and FeNO were significantly different in the three groups (p < .001). A strong inverse correlation between FeNO and BHR was found in patients with asthma and with asthma and rhinitis (r = −0.63 and r = −0.61, respectively). A cutoff of 32 ppb of FeNO was a predictive factor for BHR. Conclusions. This study highlights the relevance of FeNO as possible marker for BHR in allergic children and underlines the close link between upper and lower airways.

Accuracy of BIS value for monitoring depth of sevoflurane-nitrous oxide anesthesia in children

Objective To evaluate the accuracy of BIS value for monitoring the depth of sevoflurane-nitrous oxide in children. Methods Seventy-two ASA Ⅰ or Ⅱ children aged 1-14 yr undergoing abdominal surgery were randomly assigned into 3 groups （ n = 24 each） ：sevoflurane group （group S）, sevoflurane ＋ 30% N2O group （group SN1 ）and sevoflurane ＋ 60% N2O （group SN2 ）. Anesthesia was induced with atropine, lidocaine, propofol, rocuronium and remifentanil. After tracheal intubation, the patients were mechanically ventilated. PETCO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with 2.5% sevoflurane combined with 0, 30% and 60% nitrous oxide in group S, SN1 and SN2 respectively. The end-tidal sevoflurane concentration （CETSev） was maintained at 2.5%, 2.0% and 1.5%. Each CETSev was maintained for at least 10 min after the begining of the surgery. Then the CETSev was modified to maintain BIS value at 40-60. BIS value was recorded before anesthesia induction and each stable CETSev. CETSev was recorded at maintaining BIS value of 40-60 for at least 20 min （ C50 ）.Results BIS value and C50 were significantly lower in group SN2 than in group S and SN1 （ P 〈 0.05）, while no significant difference was found between group S and SN1 （ P 〉 0.05）. BIS value was negatively correlated with CETSev in all 3 groups （r = -0.736, -0.817, -0.729, P 〈 0.01）.There was no significant difference in the correlation coefficients among the 3 groups （ P 〉 0.05 ）. Conclusion BIS value can accurately reflect the depth of sevoflurane-nitrous oxide anesthesia in children. Key words: Electroencephalography; Monitoring, intraoperative; Anesthetics, inhalation; Nitrous oxide; Child

Tonic inhibition of human small intestinal motility by nitric oxide in children but not in adults

Gastrointestinal motility is dependent on neural influences that largely involve the enteric nervous system (ENS). The main motor patterns that occur in the fasted and fed state are noticeably different in children compared with adults. Although the development of the ENS continues after birth, there is no data on the contractile activity of segments of small intestine from young children. This study was designed to provide data on the development of muscle control by the human ENS with particular attention to acetylcholine (ACh) and nitric oxide (NO) as the primary neurotransmitters of enteric motor neurons, respectively. Small intestinal specimens were obtained from 11 children and six adults undergoing surgery for various diseases. The mechanical activity of the circular muscle was recorded in vitro. The effects of N(ω)-nitro-L-arginine methyl ester hydrochloride, an inhibitor of NO synthesis, and of atropine, an antagonist of muscarinic receptors, were tested on the spontaneous motility and responses to nerve stimulation. Spontaneous motility was observed in all preparations. Responses to nerve stimulation were identical in child and adult. No tonic cholinergic excitation of small intestinal motility was observed either in child or in adult. Inhibition of NO synthesis induced a major disinhibition of motility in child but not in adult. Spontaneous intestinal motility and cholinergic and nitrergic neurotransmission are present from birth. NO provides a tonic inhibition of intestinal motility only in child. Our study indicates that NO may be a major player in shaping the ontogenic development of intestinal motility in human.

Consistently high levels of exhaled nitric oxide in children with asthma

Exhaled nitric oxide (eNO) levels in children are unstable because they are regulated by many potent factors. The purpose of the current study was to evaluate the reliability of eNO levels between a long interval and other lung functions in normal and asthmatic children. Eighty-three elementary school children (aged 11-12 years; male : female, 39 : 44) participated in this study. Lung function, airway resistance and eNO levels were measured twice: the first measurement was in autumn 2007, and the second was one year later. There were 62 non-asthmatic control children (male : female, 31 : 31) and 21 asthmatic children (male : female, 8 : 13). In both the first and the second examination, the levels of eNO in children with asthma were higher than those in children without asthma. The parameters of lung function and the respiratory resistance in children without asthma showed a good correlation between the results of the first and second examinations. The eNO level in non-asthmatic children showed a good correlation between the two. On the other hand, the peripheral airway parameters of lung function and the respiratory resistance in children with asthma were not correlated between the first and the second examinations. The eNO level in these patients was well correlated between the two examinations. These data suggest that the eNO level showed good reproducibility in children with and without asthma. The eNO level is therefore considered to be a useful marker for reproducibly evaluating a subject's airway condition.

Optimal bolus dose of alfentanil for successful tracheal intubation during sevoflurane induction with and without nitrous oxide in children

The goals of this study were to determine the effective bolus dose of alfentanil required for successful tracheal intubation during inhalation induction using sevoflurane 5% without neuromuscular block in children, and whether nitrous oxide reduces these doses. Fifty paediatric patients, aged 3-10 yr, were randomly assigned to one of the two groups. Subjects received either sevoflurane 5% in oxygen 100% (O(2) group, n=25) or sevoflurane 5% in oxygen 40% and nitrous oxide 60% (N(2)O group, n=25) through a face mask. One minute after inhalation induction, a predetermined dose of alfentanil was injected over 15 s. The alfentanil dose was determined using Dixon's up-and-down method, starting from alfentanil 14 microg kg(-1). The trachea was intubated 3 min after inducing anaesthesia. The ED(50) [95% confidence interval (CI)] of alfentanil for successful tracheal intubation was 11.5 (9.9-13.1) and 8.6 (7.4-9.8) microg kg(-1) in the O(2) and N(2)O groups, respectively. The ED(50) of the N(2)O group was significantly lower than that of the O(2) group (P=0.0146)(.) From isotonic regression, 50% effective dose (ED(50)) (95% CI) of alfentanil in the O(2) and N(2)O groups was 11.4 (9.9-13.0) and 6.5 (5.0-8.1) microg kg(-1), respectively. The effective bolus dose of alfentanil for successful tracheal intubation was 11.5 microg kg(-1) in 50% of children during inhalation induction using sevoflurane 5% without neuromuscular blocking agent. Addition of nitrous oxide 60% in oxygen reduced the effective alfentanil dose by 25%.

Nasal nitric oxide in children with adenoidal hypertrophy: A preliminary study

Objective Nasal nitric oxide, a mediator involved in upper airway inflammation, is impaired in children with allergic rhinitis and rhinosinusitis. Normal values are 200–450 parts per billion, but no data are available concerning its levels in children with adenoidal obstruction, predisposing to chronic nasosinusal inflammation. This study aimed to: (1) measure nasal nitric oxide levels in non-allergic children with adenoidal hypertrophy and (2) assess its possible relationship with the degree of adenoidal hypertrophy and other variable (gender, age, body max index, passive smoking exposure, recurrent acute otitis media, recurrent respiratory infections, and hypertrophy of nasal turbinates). Methods Eighty-one children with suspected adenoidal hypertrophy underwent nasal fibroendoscopy to assess the degree of adenoidal hypertrophy, and nasal nitric oxide on-line measurements by means of a dedicated chemiluminescence analyser. Results Nasal nitric oxide was successfully measured in 35 patients, most of whom had levels >450 parts per billion; the values were significantly higher ( p = 0.031) in children with non-obstructive adenoids. There was no significant correlation with any other variable. Conclusions Preliminary data show above-normal nasal nitric oxide levels in children with adenoidal hypertrophy, especially those with non-obstructive adenoids. This suggests nitric oxide involvement in recurrent nasopharyngeal inflammation due to adenoidal hypertrophy.

Leukocyte DNA damage in children with iron deficiency anemia: effect of iron supplementation

Iron deficiency is frequently associated with anemia. Iron is a transition-metal ion, and it can induce free radical formation, which leads to formation of various lesions in DNA, proteins, and lipids. The aim of this study was to investigate baseline oxidative DNA damage and to clarify the role of the administration of a therapeutic dose of iron on DNA oxidation in children with iron deficiency anemia (IDA). Twenty-seven children with IDA and 20 healthy children were enrolled in the study. Leukocyte DNA damage (strand breaks and Fpg-sensitive sites) was assessed using comet assay before and after 12 weeks of daily iron administration. Before the iron administration, the frequency of DNA strand breaks in the children with IDA was found to be lower than those in the control group (P < 0.05), but there was not a significant difference for frequency of Fpg-sensitive sites. After 12 weeks of iron administration, the frequency of both DNA strand breaks and Fpg-sensitive sites were found to be increased (P < 0.01). No significant association was determined between DNA damage parameters and hemoglobin, hematocrit, serum iron, total iron binding capacity, and ferritin. In conclusion, basal level of DNA strand breaks is at a low level in children with IDA. After iron administration, DNA strand breaks and Fpg-sensitive sites, which represent oxidatively damaged DNA, increased. However, this increase was unrelated to serum level of iron and ferritin.

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 μm, 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 PM2.5. Differences between high versus low exposure in non-asthmatics resulted in an FeNO increase ranging from 45% for indoor acetaldehyde to 62% for indoor PM2.5. 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 Children Under 4 Years of Age With Recurrent Bronchitis

Background The objective of the study was to assess bronchial inflammation in preschool children with recurrent bronchitis by measuring exhaled nitric oxide. Patients and Methods The study included patients under 4 years of age with at least 3 episodes of wheezing in the past year (n=63) and a control group (n=30). Exhaled nitric oxide was measured in samples collected offline during spontaneous tidal breathing with a face mask and stored in Mylar balloons. Results The fractional exhaled nitric oxide concentration (FE NO) was higher in the group with bronchitis (mean [SD], 5.3 [1.3] parts per billion [ppb]) than in the control group (4.6 [1.1] ppb) ( P=.02). There was a significant difference between the control group and children in the bronchitis group not treated with inhaled corticosteroids ( P<.05), but not between controls and corticosteroid-treated patients. A relationship with eosinophil count was observed in that those with higher counts (>400 mL) had higher FE NO levels ( P<.01). No relationship was observed between FE NO and a positive methacholine challenge test. Follow-up lasted at least 20 months. The initial FE NO level did not differ significantly according to whether patients were subsequently transient, infrequent, or frequent wheezers (5.2 [0.98] ppb, 5.6 [1.5] ppb, and 4.8 [1.34] ppb, respectively; P=.36). Conclusions In children under 4 years of age with recurrent wheezing bronchitis who were asymptomatic at study entry, a small increase in FE NO was observed although there was a good deal of overlap with the control group.

Sildenafil for the Treatment of Pulmonary Hypertension in Pediatric Patients

Sildenafil is a phosphodiesterase 5 inhibitor widely used for the treatment of pulmonary hypertension in children. Despite limited available safety and efficacy evidence, use of sildenafil continues to increase. To date, sildenafil use for pediatric pulmonary hypertension has been characterized for 193 children through 16 studies and 28 case series and reports. The primary efficacy data suggest that sildenafil is beneficial for facilitating the weaning of inhaled nitric oxide in children after cardiac surgery. Compiled safety data suggest that sildenafil is well tolerated among children with idiopathic pulmonary arterial hypertension and pulmonary arterial hypertension associated with congenital heart disease. This review summarizes the available data describing the use, safety, and efficacy of sildenafil for children with pulmonary hypertension.

Effects of the Indoor Environment on the Fraction of Exhaled Nitric Oxide in School-Aged Children

The fractional concentration of exhaled nitric oxide (FeNO) appears to be a good marker for airway inflammation in children with asthma. To evaluate the effect of environmental exposures on exhaled nitric oxide in a community sample of children. The relationship among exhaled nitric oxide, underlying disease and home environmental exposures was examined using questionnaire data and measurement of exhaled nitric oxide in a cross-sectional study of 1135 children that included healthy children, and children with allergies and/or asthma who were attending grades 4 through 6 in Windsor, Ontario. Among healthy children, there was a positive association between FeNO and occupancy (P<0.02). Compared with forced air and hot water radiant heat, electric baseboard heating was associated with a significant increase of FeNO in healthy children (P=0.007) and children with allergies (P=0.043). FeNO was not associated with environmental tobacco smoke exposure or reported surface mold. The presence of pet dog(s), but not cats, was associated with a significantly lower FeNO in healthy children (P<0.001) and in children with reported allergies (P<0.001). The type of heating system, but not previously reported environmental tobacco smoke or mold exposure appears to affect exhaled nitric oxide in children. Exposure to different types of pets may have disparate effects on airway inflammation.