Non-asthmatic Adults Research Articles

Comparison of Fasting Plasma Glucose, Lipid Profile and Small Dense Low Density Lipoprotein in Severe Persistent Asthmatic and Non-Asthmatic Adults

Comparison of Fasting Plasma Glucose, Lipid Profile and Small Dense Low Density Lipoprotein in Severe Persistent Asthmatic and Non-Asthmatic Adults

Accelerated decline in lung function in adults with a history of remitted childhood asthma.

A significant number of children with asthma show remission in adulthood. Although these adults are often diagnosed with COPD in later life, the effect of clinically remitted childhood asthma on the decline in lung function during adulthood is uncertain. We examined whether clinical remission of childhood asthma was associated with an accelerated decline in lung function in apparently nonasthmatic adults. 3584 participants (mean (range) age 48.1 (35-65) years) who did not have adulthood asthma and other lung diseases and had normal lung function at the baseline visit were included. They were categorised as those with remitted childhood asthma (n=121) and healthy controls (n=3463) according to their self-reported childhood asthma history. Spirometry was performed at baseline and follow-up visits. The mean follow-up was 5.3 years. Multivariate regression analysis showed that remitted childhood asthma and smoking were independently associated with a rapid decline in forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Smoking was an independent predictor of a rapid decline in FEV1/FVC. The annual decline in FEV1 and FVC was significantly greater in participants with remitted childhood asthma than in healthy controls, and the differences remained significant after adjusting for the propensity score. A history of clinically remitted childhood asthma is an independent risk factor for accelerated decline in lung function in adults. Remitted childhood asthma and smoking may additively accelerate the development of obstructive lung disease.

Association between E-cigarette use and chronic obstructive pulmonary disease in non-asthmatic adults in the USA.

Concern about the health impacts of e-cigarette use is growing; however, limited research exists regarding potential long-term health effects of this behavior. This study explored the relationship between e-cigarette use and COPD in a sample of US adults. A secondary data analysis using data from the 2018 Behavioral Risk Factor Surveillance Survey in the USA was computed to examine associations between e-cigarette use and COPD controlling for conventional cigarette smoking status, past month leisure physical activity and demographic characteristics including age, sex, education, race, marital status and body mass index. Significant associations between e-cigarette use and COPD among former combustible cigarette smokers and those who reported never using combustible cigarettes were found. Compared with never e-cigarette users, the odds of having COPD were significantly greater for daily e-cigarette users (OR=1.53; 95% CI: 1.11-2.03), occasional users (OR=1.43, 95% CI: 1.13-1.80) and former users (OR=1.46 95% CI: 1.28-1.67). Findings from this study indicate a potential link between e-cigarette use and COPD. Further research to explore the potential effects of e-cigarette on COPD is recommended.

Effects of Oral Procaterol for Postinfectious Cough in Adults: Single-Centre, Randomized Double-Blind, Placebo-Controlled Trial.

BackgroundPersistent cough following an upper respiratory tract infection (URTI) is common in clinical practice. We investigated the effects of procaterol on cough-specific quality of life (QoL) and peripheral-airway function among adults suffering from postinfectious cough (PIC).MethodsThis was a prospective, randomized, double-blinded placebo-controlled trial (NCT 02349919) conducted at a university hospital. Seventy-four non-asthmatic adults who had persistent post-URTI cough for ≥3 weeks were assessed by a physical examination, chest/paranasal sinus radiographs, spirometry, and impulse oscillometry (IOS) and were allocated to receive procaterol or placebo for 4 weeks. The Thai version of the Leicester Cough Questionnaire (LCQ-T), spirometry and IOS were assessed at baseline, 2 weeks, and 4 weeks.ResultsMean LCQ-T total scores for the procaterol group (10.8) and placebo group (10.9) at baseline were not significantly different (P=0.821). After adjustment for baseline Borg Cough Scale score and post-nasal drip, the mean between-group difference was not significant for LCQ-T total score (-1.26; 95% confidence interval [CI], -2.69 to 0.17), physical domain score (-0.35; 95% CI, -0.76 to 0.06), psychological domain score (-0.53; 95% CI, -1.06 to 0.01), or social domain score (-0.38; 95% CI, -0.92 to 0.16). Large improvements in LCQ-T total score were reported in both groups after 2 weeks (procaterol, 4.21±2.73; placebo, 5.34±3.2), and 4 weeks (procaterol, 5.94±3.68; placebo, 7.07±3.44). No differences between groups were found in the mean changes of spirometry or IOS parameters after 4 weeks.ConclusionOur study shows that procaterol is not effective in the treatment of PIC, in terms of improvement of cough-specific QoL or peripheral-airway function.

Economic evaluation of the OSAC randomised controlled trial: oral corticosteroids for non-asthmatic adults with acute lower respiratory tract infection in primary care

ObjectiveTo estimate the costs and outcomes associated with treating non-asthmatic adults (nor suffering from other lung-disease) presenting to primary care with acute lower respiratory tract infection (ALRTI) with oral corticosteroids...

Higher mortality of adults with asthma: A 15‐year follow‐up of a population‐based cohort

Higher all-cause mortality in asthmatics has been shown previously. Polysensitization is associated with higher morbidity among asthmatic children, and allergic rhinitis and/or allergic conjunctivitis (AR/AC) are associated with higher morbidity in adult asthmatics. Little is known about the effect of AR/AC and other factors on mortality among adult asthmatics. The aim was to study mortality and its risk factors in adults with and without asthma. We randomly selected 1648 asthmatics with age over 30 years from national registers and matched the asthma sample with one or two controls. Baseline information was obtained by a questionnaire in 1997, and the study population was linked with the death certificate information of Statistics Finland from 1997 to 2013. Overall and cause-specific survival between the groups was compared in several adjusted models. During a mean follow-up period of 15.6 years, 221 deaths among 1052 asthma patients and 335 deaths among 1889 nonasthmatics were observed. Cardiovascular diseases were the main cause of death in both groups. Asthma was associated with increased all-cause mortality (adjusted HR 1.25; 95% CI 1.05-1.49, P = .011) as well as mortality from chronic obstructive pulmonary disease (HR 12.0, 4.18-34.2, P < .001) and malignant neoplasms of respiratory organs (HR 2.33, 1.25-4.42, P = .008). Among asthmatics, smoking was associated with increased all-cause mortality, and self-reported AR/AC was associated with decreased mortality. Among nonasthmatics, smoking, and obesity were associated with increased all-cause mortality, whereas female gender showed an association with a decreased risk. Increased mortality among adult asthmatics was largely explained by the development of COPD, malignant respiratory tract neoplasms, and cardiovascular diseases. Smoking cessation is important for reduction in total mortality in both asthmatic and nonasthmatic adults. AR/AC was associated with decreased mortality only in asthmatics. Thus, studies in other populations of larger size are needed to explore further the nature of this association.

Neighborhood Perceptions and Cumulative Impacts of Low Level Chronic Exposure to Fine Particular Matter (PM2.5) on Cardiopulmonary Health.

Adverse perceptions of neighborhood safety, aesthetics and quality including access to resources can induce stress and may make individuals more sensitive to cardiopulmonary effects of air pollution exposure. Few studies have examined neighborhood perceptions as important and modifiable non-chemical stressors of the built environment that may exacerbate effects of air pollution on cardiopulmonary health outcomes, particularly among general population based cohorts. This study examined associations between low-level chronic exposure to fine particulate matter (PM2.5) and cardiopulmonary health, and the potential mediating or modifying effects of adverse neighborhood perceptions. Using data from the Survey of the Health of Wisconsin (SHOW), 2230 non-asthmatic adults age 21–74 were included in the analyses. The overall goals of this study were to assess if individuals who experience stress from neighborhood environments in which they live were more sensitive to low levels of fine particular matter (PM2.5 μg/m3). Demographic predictors of air pollution exposure included younger age, non-White race, lower education and middle class income. After adjustments, objective lung function measures (FEV1 and FEV1 to FVC ratio) were the only cardiopulmonary health indicators significantly associated with chronic three-year annual averages of PM2.5. Among all non-asthmatics, a ten unit increase in estimated three year annual average PM2.5 exposure was significantly associated with lower forced expiratory volume (L) in one second FEV1 (β = −0.40 μg/L; 95% CI −0.45, −0.06). Among all individuals, adverse perceptions of the neighborhood built environment did not appear to statistically moderate or mediate associations. However, stratified analysis did reveal significant associations between PM2.5 and lung function (FEV1) only among individuals with negative perceptions and increased reports of neighborhood stressors. These findings included individuals who felt their neighborhoods were poorly maintained (β = −0.82; 95% CI −1.35, −0.28), experienced stress from crime (β = −0.45; 95% CI −0.94, 0.04) or reported neighborhood is not well maintained (β = −1.13, CI −2.04, −0.24). These significant associations were similar for FEV1 to FVC ratio. Multi-pronged approaches addressing both neighborhood built environment aesthetics and air pollution regulation may be necessary to protect vulnerable and susceptible individuals and reduce persistent inequalities.

Effect of Oral Prednisolone on Symptom Duration and Severity in Nonasthmatic Adults with Acute Lower Respiratory Infection - A Randomized Clinical Trial: Hay AD, Little P, Harnden A, et al. JAMA. 2017;318(8):721-730

Effect of Oral Prednisolone on Symptom Duration and Severity in Nonasthmatic Adults with Acute Lower Respiratory Infection - A Randomized Clinical Trial: Hay AD, Little P, Harnden A, et al. JAMA. 2017;318(8):721-730

Microbial characteristics in homes of asthmatic and non-asthmatic adults in the ECRHS cohort.

Microbial exposures in homes of asthmatic adults have been rarely investigated; specificities and implications for respiratory health are not well understood. The objectives of this study were to investigate associations of microbial levels with asthma status, asthma symptoms, bronchial hyperresponsiveness (BHR), and atopy. Mattress dust samples of 199 asthmatics and 198 control subjects from 7 European countries participating in the European Community Respiratory Health Survey II study were analyzed for fungal and bacterial cell wall components and individual taxa. We observed trends for protective associations of higher levels of mostly bacterial markers. Increased levels of muramic acid, a cell wall component predominant in Gram-positive bacteria, tended to be inversely associated with asthma (OR's for different quartiles: II 0.71 [0.39-1.30], III 0.44 [0.23-0.82], and IV 0.60 [0.31-1.18] P for trend .07) and with asthma score (P for trend .06) and with atopy (P for trend .02). These associations were more pronounced in northern Europe. This study among adults across Europe supports a potential protective effect of Gram-positive bacteria in mattress dust and points out that this may be more pronounced in areas where microbial exposure levels are generally lower.

Effect of Oral Prednisolone on Symptom Duration and Severity in Nonasthmatic Adults With Acute Lower Respiratory Tract Infection

Acute lower respiratory tract infection is common and often treated inappropriately in primary care with antibiotics. Corticosteroids are increasingly used but without sufficient evidence. To assess the effects of oral corticosteroids for acute lower respiratory tract infection in adults without asthma. Multicenter, placebo-controlled, randomized trial (July 2013 to final follow-up October 2014) conducted in 54 family practices in England among 401 adults with acute cough and at least 1 lower respiratory tract symptom not requiring immediate antibiotic treatment and with no history of chronic pulmonary disease or use of asthma medication in the past 5 years. Two 20-mg prednisolone tablets (n = 199) or matched placebo (n = 202) once daily for 5 days. The primary outcomes were duration of moderately bad or worse cough (0 to 28 days; minimal clinically important difference, 3.79 days) and mean severity of symptoms on days 2 to 4 (scored from 0 [not affected] to 6 [as bad as it could be]; minimal clinically important difference, 1.66 units). Secondary outcomes were duration and severity of acute lower respiratory tract infection symptoms, duration of abnormal peak flow, antibiotic use, and adverse events. Among 401 randomized patients, 2 withdrew immediately after randomization, and 1 duplicate patient was identified. Among the 398 patients with baseline data (mean age, 47 [SD, 16.0] years; 63% women; 17% smokers; 77% phlegm; 70% shortness of breath; 47% wheezing; 46% chest pain; 42% abnormal peak flow), 334 (84%) provided cough duration and 369 (93%) symptom severity data. Median cough duration was 5 days (interquartile range [IQR], 3-8 days) in the prednisolone group and 5 days (IQR, 3-10 days) in the placebo group (adjusted hazard ratio, 1.11; 95% CI, 0.89-1.39; P = .36 at an α = .05). Mean symptom severity was 1.99 points in the prednisolone group and 2.16 points in the placebo group (adjusted difference, -0.20; 95% CI, -0.40 to 0.00; P = .05 at an α = .001). No significant treatment effects were observed for duration or severity of other acute lower respiratory tract infection symptoms, duration of abnormal peak flow, antibiotic use, or nonserious adverse events. There were no serious adverse events. Oral corticosteroids should not be used for acute lower respiratory tract infection symptoms in adults without asthma because they do not reduce symptom duration or severity. ISRCTN.com Identifier: ISRCTN57309858.

Down-Regulation of Cough during Exercise Is Less Frequent in Healthy Children than Adults. Role of the Development and/or Atopy?

Cough is typically associated with physical activity in children with asthma, but the characteristics of the relationship between cough and exercise has not been established under physiological conditions. The aim of the study was to describe the effect of exercise on the reflex cough response elicited by a single breath of capsaicin in non-asthmatic children. A group of non-asthmatic adults was studied as reference. Thirty children and 29 adults were recruited. The cough reflex sensitivity to capsaicin was first determined to establish the dose that provokes 5 cough efforts (C5). The number of coughs elicited by C5 (NC5) was then compared at baseline and during a standardized submaximal treadmill exercise. Data are expressed as median (interquartile range). Children and adults showed a significant decrease in NC5 (respectively from 5.0 (4.0–6.0) to 2.5 (2.0–4.0), p < 0.0005 and from 6.0 (5.0–7.0) to 2.0 (0.0–3.0, p < 0.0005). During exercise, NC5 was observed to decrease in all adult subjects, but in only 24/30 children (80%, p = 0.02). A trend for a higher incidence of personal and familial atopy was observed in children that lacked cough down-regulation during exercise compared with other children. It is concluded that the cough reflex response to capsaicin is down regulated by exercise in both children and adults. The effect however is less consistently observed in the former. The difference may reflect maturation of descending inhibitory pathways of the cough reflex, but may also be associated to atopy. The data stress the importance of assessing the time relationship of cough and exercise in questionnaire studies of asthma.

DNA methylation in lung cells is associated with asthma endotypes and genetic risk.

The epigenome provides a substrate through which environmental exposures can exert their effects on gene expression and disease risk, but the relative importance of epigenetic variation on human disease onset and progression is poorly characterized. Asthma is a heterogeneous disease of the airways, for which both onset and clinical course result from interactions between host genotype and environmental exposures, yet little is known about the molecular mechanisms for these interactions. We assessed genome-wide DNA methylation using the Infinium Human Methylation 450K Bead Chip and characterized the transcriptome by RNA sequencing in primary airway epithelial cells from 74 asthmatic and 41 nonasthmatic adults. Asthma status was based on doctor's diagnosis and current medication use. Genotyping was performed using various Illumina platforms. Our study revealed a regulatory locus on chromosome 17q12-21 associated with asthma risk and epigenetic signatures of specific asthma endotypes and molecular networks. Overall, these data support a central role for DNA methylation in lung cells, which promotes distinct molecular pathways of asthma pathogenesis and modulates the effects of genetic variation on disease risk and clinical heterogeneity.

Simulation of Forced Expiration in a Biophysical Model, With Homogeneous and Clustered Bronchoconstriction.

One limitation of forced spirometry is that it integrates the contribution of the complex and dynamic behavior of all of the airways and tissue of the lung into a single exhaling unit, hence, it is not clear how spirometric measures are affected by local changes to the airways or tissue such as the presence of "ventilation defects." Here, we adapt a wave-speed limitation model to a spatially distributed and anatomically based airway tree that is embedded within a deformable parenchyma, to simulate forced expiration in 1 s (FEV1). This provides a model that can be used to assess the consequence of imposed constrictions on FEV1. We first show how the model can be parameterized to represent imaging and forced spirometry data from nonasthmatic healthy young adults. We then compare the effect of homogeneous and clustered bronchoconstriction on FEV1 in six subject-specific models (three male and three female). The model highlights potential sources of normal subject variability in response to agonist challenge, including the interaction between sites of airway constriction and sites of flow limitation at baseline. The results support earlier studies which proposed that the significant constriction of nondefect airways must be present in order to match to clinical measurements of lung function.

ADRB2 Polymorphism and Salbutamol Responsiveness in Northern Indian Children with Mild to Moderate Exacerbation of Asthma.

The primary objective was to determine the association between beta-2 adrenergic receptor (ADRB2) gene polymorphism (rs1042713, c.46A>G, p.Arg16Gly) and the response to inhaled salbutamol in North Indian children aged 5 to 15 years, with mild to moderate exacerbation of asthma. This cross-sectional study was done at a tertiary-care hospital in Northern India from June 2011 to May 2013. 120 children with asthma with mild to moderate exacerbation underwent spirometry at baseline and after administration of three doses of salbutamol. An increase in FEV1 =15% was considered as positive response. Blood samples from these children were analysed for ADRB2 polymorphism (p.Arg16Gly). 94 non-asthmatic adult controls were also studied to determine the prevalence of ADRB2 polymorphism. In asthmatic children, the frequency of AA, GG, AG genotypes were 24.2%, 24.2% and 51.7% compared to 20.2%, 20.2% and 59.6%, respectively in the non-asthmatic adults. Salbutamol responsiveness showed no correlation with the studied ADRB2 polymorphism (p= 0.55). A trend towards greater bronchodilator responsiveness amongst AA genotype, compared to GG genotype was observed (Median change in percent predicted FEV1 14.5% and 7.5%, respectively). No correlation was found between salbutamol responsiveness and ADRB2 genotype in Northern Indian children with asthma with mild-to moderate exacerbation.

Allergic Non-Asthmatic Adults Have Regional Pulmonary Responses to Segmental Allergen Challenge.

BackgroundAllergic non-asthmatic (ANA) adults experience upper airway symptoms of allergic disease such as rhinorrhea, congestion and sneezing without symptoms of asthma. The aim of this study was to utilize PET-CT functional imaging to determine whether allergen challenge elicits a pulmonary response in ANA subjects or whether their allergic disease is truly isolated to the upper airways.MethodsIn 6 ANA subjects, bronchoalveolar lavages (BAL) were performed at baseline and 24h after instillation of an allergen and a diluent in separate lung lobes. After instillation (10h), functional imaging was performed to quantify and compare regional perfusion, ventilation, fractional gas content (Fgas), and glucose uptake rate (Ki) between the baseline, diluent and allergen lobes. BAL cell counts were also compared.ResultsIn ANA subjects, compared to the baseline and diluent lobes, perfusion and ventilation were significantly lower in the allergen lobe (median [inter-quartile range], baseline vs. diluent vs. allergen: Mean-normalized perfusion; 0.87 [0.85–0.97] vs. 0.90 [0.86–0.98] vs. 0.59 [0.55–0.67]; p<0.05. Mean-normalized ventilation 0.89 [0.88–0.98] vs. 0.95 [0.89–1.02] vs. 0.63 [0.52–0.67], p<0.05). In contrast, no significant differences were found in Fgas between baseline, diluent and allergen lobes or in Ki. Total cell counts, eosinophil and neutrophil cell counts (cells/ml BAL) were significantly greater in the allergen lobe compared to the baseline lobe (all P<0.05).ConclusionsDespite having no clinical symptoms of a lower airway allergic response (cough and wheeze) allergic non-asthmatic subjects have a pulmonary response to allergen exposure which manifests as reduced ventilation and perfusion.

Reference ranges for induced sputum eosinophil counts in Korean adult population.

BackgroundInduced sputum analyses are widely utilized to evaluate airway inflammation in asthmatics. However, the values have not been examined in Korean adults.ObjectiveThe purpose of this study is to determine reference ranges for induced sputum eosinophils and their influencing factors in Korean adults.MethodsA total of 208 healthy nonasthmatic adults were recruited. Sputum induction and processing followed the international standard protocols.ResultsAdequate sputum samples were successfully collected from 81 subjects (38.9%). The upper 90 percentile for sputum eosinophil was calculated as 3.5%. The median value of eosinophil count percentage was significantly higher in subjects with atopy than those without atopy (median, 1.6%; range, 0-11.0% vs. median, 0%; range 0-3.6%, p=0.030). However, no significant correlations were found with age, gender, body mass index, smoking status, blood eosinophil, or fractional exhaled nitric oxide levels.ConclusionCurrent study was the first attempt to determine the reference ranges of induced sputum eosinophils in Korean adults. The cutoff value for sputum eosinophilia was 3.5%, and was significantly associated with atopy.

Effects of altered airway function on exercise ventilation in asthmatic adults.

Variable airway function is a central feature of the asthmatic condition. Thus, habitually active asthmatics are certain to exercise under conditions of variable airway (dys)function. The purpose of this study was to determine the effects of variable preexercise airway function on ventilation during whole-body exercise in asthmatic adults. Eight mild asthmatic (age = 26 yr; V˙O2peak = 49 mL·kg·min) and nine nonasthmatic (age = 30 yr; V˙O2peak = 46 mL·kg·min) adults performed constant workrate cycling exercise to exhaustion after four separate interventions: 1) a control trial (CON); 2) inhalation of fast-acting β2-agonist (BD); 3) eucapnic voluntary hyperpnea challenge (BC); and 4) sham to the hyperpnea (SHAM). Pulmonary function was assessed at baseline and after each intervention. Exercise ventilation and operating lung volumes were compared among the four exercise trials in both control and asthmatic subjects. Baseline pulmonary function was significantly lower in asthmatic subjects compared with control subjects. In asthmatic subjects, postintervention (i.e., preexercise) forced expiratory volume 1.0 s was significantly different among the four exercise trials (CON = 3.5 ± 0.4, BD = 4.1 ± 0.4, SHAM = 3.6 ± 0.3, BC = 2.8 ± 0.3 L, P < 0.05), whereas it was not different in control subjects. There were no differences in exercise ventilation or operating lung volumes during exercise among the four trials either within asthmatic subjects or between control and asthmatic subjects. These findings suggest that the state of airway function-whether bronchodilated or bronchoconstricted-before exercise in the mild asthmatic does not affect the exercise ventilatory response. Thus, ventilatory system function in the asthmatic appears to be responsive to the acute requirement for increased airflow during whole-body exercise.

Indoor molds and lung function in healthy adults

Indoor mold exposure is common worldwide and constitutes an important health problem. There are very few studies assessing the relation between mold exposure and lung function levels among non-asthmatic adults. Our objective was to assess the relations between dampness and mold exposures at home and at work and lung function. In particular, we elaborated the importance of different exposure indicators. In a population-based study, 269 non-asthmatic adults from South Finland answered a questionnaire on indoor dampness and mold exposures at home or at work and other factors potentially influencing lung function, and performed spirometry. Multiple linear regression model was applied to study the relations between exposures and spirometric lung function levels. In linear regression adjusting for confounding, FEV1 level was reduced on average 200ml related to mold odor at home (effect estimate -0.20, 95% CI -0.60 to 0.21) and FVC level was reduced on average 460ml (-0.46, -0.95 to 0.03) respectively. Exposure to mold odor at home or at work or both was related to reduced FEV1 (-0.15, -0.42 to 0.12) and FVC (-0.22, -0.55 to 0.11) levels. Women had on average 510ml reduced FEV1 levels (-0.51, -1.0 to 0.03) and 820ml reduced FVC levels (-0.82, -1.4 to -0.20) related to mold odor exposure at home. Mold odor exposure was related to lower lung function levels among non-asthmatic adults, especially among women.

Relationship between airway neutrophilia and ageing in asthmatics and non‐asthmatics

Increased sputum neutrophilia has been observed in asthma, but also during normal ageing in asthmatics and non-asthmatics. It remains unclear what constitutes 'normal' neutrophil levels in different age groups. We assessed the relationship between age and airway neutrophils of 194 asthmatics and 243 non-asthmatics (age range: 6-80 years). Regression analyses were used to assess this relationship adjusted for confounders including asthma status, atopy, gender, smoking and current use of inhaled corticosteroids (ICS). Age-corrected reference values for different age groups were determined using the 95th percentile of non-asthmatic participants. Age was positively associated with sputum neutrophils in both asthmatic and non-asthmatic adults (0.46% neutrophil increase/year (95% confidence interval (CI) 0.18, 0.73) and 0.44%/year (0.25, 0.64, respectively), but no association was found in the <20-year age category. Individuals with high sputum neutrophil counts (>95th percentile of non-asthmatic counts for any given age group) were significantly more likely to be asthmatic (odds ratio = 2.5; 95% CI: 1.3, 5.0), with the greatest effect observed in the older age group. Other factors that independently associated with increased sputum neutrophil levels included atopy in non-asthmatic adults, male gender and current use of ICS in asthmatic adults. Age-specific reference values for neutrophil percentage were under 20 years-76%, 20-40 years-62%, 40-60 years-63% and over 60 years-67%. Airway neutrophilia is related to age in adults, with a neutrophilic asthma phenotype present in older adults. The use of appropriate age-specific reference values is recommended for future studies aimed at elucidating the role of neutrophils in asthma.

The effect of ventilation, age, and asthmatic condition on ultrafine particle deposition in children.

Ultrafine particles (UFPs) contribute to health risks associated with air pollution, especially respiratory disease in children. Nonetheless, experimental data on UFP deposition in asthmatic children has been minimal. In this study, the effect of ventilation, developing respiratory physiology, and asthmatic condition on the deposition efficiency of ultrafine particles in children was explored. Deposited fractions of UFP (10–200 nm) were determined in 9 asthmatic children, 8 nonasthmatic children, and 5 nonasthmatic adults. Deposition efficiencies in adults served as reference of fully developed respiratory physiologies. A validated deposition model was employed as an auxiliary tool to assess the independent effect of varying ventilation on deposition. Asthmatic conditions were confirmed via pre-and post-bronchodilator spirometry. Subjects were exposed to a hygroscopic aerosol with number geometric mean diameter of 27–31 nm, geometric standard deviation of 1.8–2.0, and concentration of 1.2 × 106 particles cm−3. Exposure was through a silicone mouthpiece. Total deposited fraction (TDF) and normalized deposition rate were 50% and 32% higher in children than in adults. Accounting for tidal volume and age variation, TDF was 21% higher in asthmatic than in non-asthmatic children. The higher health risks of air pollution exposure observed in children and asthmatics might be augmented by their susceptibility to higher dosages of UFP.