Airways disorders and the swimming pool

Exhaled and Systemic Biomarkers to Aid the Diagnosis of Bronchial Asthma in Elite Water Sports Athletes

PURPOSE

Our aim was to evaluate the accuracy of a combined airway inflammatory biomarker assessment in diagnosing asthma in elite water sports athletes.

METHODS

Members of the Hungarian Olympic and Junior Swim Team and elite athletes from other aquatic disciplines were assessed for asthma by objective lung function measurements, and blood eosinophil count (BEC), serum total immunoglobulin E (IgE), fractional exhaled nitric oxide (F ENO ) measurements, and skin prick testing were performed. A scoring system from BEC, F ENO , serum IgE, and skin test positivity was constructed by dichotomizing the variables and assigning a score of 1 if the variable is elevated. These scores were summed to produce a final composite score ranging from 0 to 4.

RESULTS

A total of 48 participants were enrolled (age 21 ± 4 yr, 42% male), of which 22 were diagnosed with asthma. Serum total IgE and F ENO levels were higher in asthmatic individuals (68 [27-176] vs 24 [1-43], P = 0.01; 20 [17-26] vs 15 [11-22], P = 0.02), and positive prick test was also more frequent (55% vs 8%, P < 0.01). Asthmatic participants had higher composite variable scores (2 [1-3] vs 1 [0-1], P = 0.02). Receiver operating characteristic analysis showed that total IgE, F ENO , and composite variable were suitablefor identifying asthmatic participants (area under the curve = 0.72, P = 0.01; 0.70, P = 0.02, and 0.69, P = 0.03). A composite score of >2 reached a specificity of 96.2%, a sensitivity of 36.4%, and a likelihood ratio of 9.5. Logistic regression model revealed a strong association between the composite variable and the asthma diagnosis (OR = 2.71, 95% confidence interval = 1.17-6.23, P = 0.02).

CONCLUSIONS

Our data highlight the diagnostic value of combined assessment of Th2-type inflammation in elite water sports athletes. The proposed scoring system may be helpful in ruling in asthma in this population upon clinical suspicion.

software development TO OPTIMIZE THE minimal detectable difference IN huMAN AIRWAY IMAGES CAPTURED USING optical coherence tomography

Optical coherence tomography (OCT) is an imaging methodology that can be used to assess human airways. OCT avoids the harmful effects of ionizing radiation and has a high spatial resolution making it well suited for imaging the structure of small airways. Analysis of OCT airway images has typically been performed manually by tracing the airway with a relatively high coefficient of variation. The purpose of this study was to develop an analysis tool to reduce the inter- and intra-observer reproducibility of OCT and improve the ability to detect differences in airways. OCT images from healthy, young human volunteers were used to develop and test the OCT software. Measurement software was developed to allow the conversion of the original image into a grayscale image and was followed by an enhancement operation to brighten the image, and contour measurement. A total of 140 OCT images, 70 small (< 2 mm) and 70 medium (2-4 mm) sized airways, were analyzed. The inter- and intra- observer reproducibility of airway measurements ranged for strong to very strong in the small sized airways. For medium sized airways the reproducibility was considered moderate. Bland-Altman bias was low between observers and observations for all measures. The minimal detectable differences in the airway measurements with our semi-automated software were lower relative to manual tracing in medium-sized airways. Our software improves the ability to perform quantitative OCT analysis and may help to quantify the extent of airway remodelling in respiratory disease or elite athletes in future studies. This article is protected by copyright. All rights reserved.

A systematic review and meta-analysis on the effectiveness of swimming on lung function and asthma control in children with asthma

BACKGROUND

Swimming has been considered the most appropriate activity for children with asthma for its lower asthmogenicity compared to land-based activities. However, the benefits of swimming have been hampered by reports of increased asthma risks, airway inflammation and bronchial hyper-responsiveness from exposure to chlorine by-products in swimming pools. Thus, the role of swimming for children with asthma remains unclear.

OBJECTIVES

To determine the effectiveness of swimming as an intervention on lung function and asthma control in children below the age of 18 years. Any adverse effects from swimming on asthma were also examined.

METHODS

Searches were performed across six databases systematically (PubMed, CINAHL, Embase, CENTRAL, Scopus, and PsycINFO). Randomized controlled trials (RCTs), quasi-experimental studies and interventional studies with at least one control/comparator group that were published in English were included. All eligible studies were screened with risk of bias examined by two independent reviewers. Meta-analyses were conducted using Review Manager 5.4 software while narrative syntheses were performed where meta-analysis was inappropriate and heterogeneity was present.

RESULTS

1710 records were retrieved from the search. A total of 9 studies with 387 participants were included in this review after screening. Swimming was found to have favourable effects on forced expiratory volume in one second (L) and forced vital capacity (%), but not for forced expiratory volume in one second (%) and peak expiratory flow (%). Narrative synthesis on asthma control and adverse effects were in favour of the swimming group.

CONCLUSION

Future studies that are adequately powered, involve swimming interventions of sufficient intensity, frequency and duration, examine cumulative exposures to chlorine by-products and take into account potential cofounders are warranted.

Evidence for alternative exhaled elimination profiles of disinfection by-products and potential markers of airway responses to swimming in a chlorinated pool environment

Chlorine-based disinfectants protect pool water from pathogen contamination but produce potentially harmful halogenated disinfection by-products (DBPs). This study characterized the bioaccumulation and elimination of exhaled DBPs post-swimming and investigated changes in exhaled breath profiles associated with chlorinated pool exposure. Nineteen participants provided alveolar-enriched breath samples prior to and 5, 90, 300, 510, and 600 minutes post-swimming. Known DBPs associated with chlorinated water were quantitated by thermal desorption-gas chromatography-mass spectrometry. Two distinct exhaled DBP elimination profiles were observed. Most participants (84%) reported peak concentrations immediately post-swimming that reduced exponentially. A sub-group exhibited a previously unobserved and delayed washout profile with peak levels at 90 minutes post-exposure. Metabolomic investigations tentatively identified two candidate biomarkers associated with swimming pool exposure, demonstrating an upregulation in the hours after exposure. These data demonstrated a hitherto undescribed exhaled DBP elimination profile in a small number of participants which contrasts previous findings of uniform accumulation and exponential elimination. This sub-group which exhibited delayed peak-exhaled concentrations suggests the uptake, processing, and immediate elimination of DBPs are not ubiquitous across individuals as previously understood. Additionally, non-targeted metabolomics highlighted extended buildup of compounds tentatively associated with swimming in a chlorinated pool environment that may indicate airway responses to DBP exposure.

Exercise-Induced Bronchoconstriction and the Air We Breathe

An association between airway dysfunction and airborne pollutant inhalation exists. Volatilized airborne fluorocarbons in ski wax rooms, particulate matter, and trichloromines in indoor environments are suspect to high prevalence of exercise-induced bronchoconstriction and new-onset asthma in athletes competing in cross-country skiing, ice rink sports, and swimming. Ozone is implicated in acute decreases in lung function and the development of new-onset asthma from exposure during exercise. Mechanisms and genetic links are proposed for pollution-related new-onset asthma. Oxidative stress from airborne pollutant inhalation is a common thread to progression of airway damage. Key pollutants and mechanisms for each are discussed.

Physical activity for children with chronic disease; a narrative review and practical applications

BACKGROUND

Physical activity (PA) is associated with a diverse range of health benefits. International guidelines suggest that children should be participating in a minimum of 60 min of moderate to vigorous intensity PA per day to achieve these benefits. However, current guidelines are intended for healthy children, and thus may not be applicable to children with a chronic disease. Specifically, the dose of PA and disease specific exercise considerations are not included in these guidelines, leaving such children with few, if any, evidence-based informed suggestions pertaining to PA. Thus, the purpose of this narrative review was to consider current literature in the area of exercise as medicine and provide practical applications for exercise in five prevalent pediatric chronic diseases: respiratory, congenital heart, metabolic, systemic inflammatory/autoimmune, and cancer.

METHODS

For each disease, we present the pathophysiology of exercise intolerance, summarize the pediatric exercise intervention research, and provide PA suggestions.

RESULTS

Overall, exercise intolerance is prevalent in pediatric chronic disease. PA is important and safe for most children with a chronic disease, however exercise prescription should involve the entire health care team to create an individualized program.

CONCLUSIONS

Future research, including a systematic review to create evidence-based guidelines, is needed to better understand the safety and efficacy of exercise among children with chronic disease.

Selective citation in the literature on swimming in chlorinated water and childhood asthma: a network analysis

Background

Knowledge development depends on an unbiased representation of the available evidence. Selective citation may distort this representation. Recently, some controversy emerged regarding the possible impact of swimming on childhood asthma, raising the question about the role of selective citation in this field. Our objective was to assess the occurrence and determinants of selective citation in scientific publications on the relationship between swimming in chlorinated pools and childhood asthma.

Methods

We identified scientific journal articles on this relationship via a systematic literature search. The following factors were taken into account: study outcome (authors' conclusion, data-based conclusion), other content-related article characteristics (article type, sample size, research quality, specificity), content-unrelated article characteristics (language, publication title, funding source, number of authors, number of affiliations, number of references, journal impact factor), author characteristics (gender, country, affiliation), and citation characteristics (time to citation, authority, self-citation). To assess the impact of these factors on citation, we performed a series of univariate and adjusted random-effects logistic regressions, with potential citation path as unit of analysis.

Results

Thirty-six articles were identified in this network, consisting of 570 potential citation paths of which 191 (34%) were realized. There was strong evidence that articles with at least one author in common, cited each other more often than articles that had no common authors (odds ratio (OR) 5.2, 95% confidence interval (CI) 3.1-8.8). Similarly, the chance of being cited was higher for articles that were empirical rather than narrative (OR 4.2, CI 2.6-6.7), that reported a large sample size (OR 5.8, CI 2.9-11.6), and that were written by authors with a high authority within the network (OR 4.1, CI 2.1-8.0). Further, there was some evidence for citation bias: articles that confirmed the relation between swimming and asthma were cited more often (OR 1.8, CI 1.1-2.9), but this finding was not robust.

Conclusions

There is clear evidence of selective citation in this research field, but the evidence for citation bias is not very strong.

Environmental influence on the prevalence and pattern of airway dysfunction in elite athletes

BACKGROUND AND OBJECTIVE

Elite swimming and boxing require athletes to achieve relatively high minute ventilation. The combination of a sustained high ventilation and provocative training environment may impact the susceptibility of athletes to exercise-induced bronchoconstriction (EIB). The purpose of this study was to evaluate the prevalence of EIB in elite Great British (GB) boxers and swimmers.

METHODS

Boxers (n = 38, mean age: 22.1 ± 3.1 years) and swimmers (n = 44, mean age: 21.1 ± 2.6 years) volunteered for the study. Athletes completed an exercise-induced respiratory symptom questionnaire, baseline assessment of fraction of exhaled nitric oxide (FeNO), maximal spirometry manoeuvres and a eucapnic voluntary hyperpnoea (EVH) challenge. EIB was confirmed if forced expiratory volume in 1 s (FEV₁ ) reduced by ≥10% from baseline at two time points post-EVH challenge.

RESULTS

The prevalence of EIB was greater in elite swimmers (30 of 44; 68%) than in boxers (3 of 38; 8%) (P < 0.001). Twenty-two out of the 33 (67%) EVH-positive athletes had no prior diagnosis of asthma/EIB. Moreover, 12% (6 of 49) of the EVH-negative athletes had a previous diagnosis of asthma/EIB. We found a correlation between FeNO and FEV₁ change in lung function post-EVH challenge in swimmers (r = 0.32; P = 0.04) but not in boxers (r = 0.24; P = 0.15).

CONCLUSION

The prevalence of EIB was ninefold greater in swimmers when compared with boxers. Athletes who train and compete in provocative environments at sustained high ventilation may have an increased susceptibility to EIB. It is not entirely clear whether increased susceptibility to EIB affects elite sporting performance and long-term airway health in elite athletes.

The World Anti-Doping Code: can you have asthma and still be an elite athlete?

KEY POINTS

The World Anti-Doping Code (the Code) does place some restrictions on prescribing inhaled β2-agonists, but these can be overcome without jeopardising the treatment of elite athletes with asthma.While the Code permits the use of inhaled glucocorticoids without restriction, oral and intravenous glucocorticoids are prohibited, although a mechanism exists that allows them to be administered for acute severe asthma.Although asthmatic athletes achieved outstanding sporting success during the 1950s and 1960s before any anti-doping rules existed, since introduction of the Code's policies on some drugs to manage asthma results at the Olympic Games have revealed that athletes with confirmed asthma/airway hyperresponsiveness (AHR) have outperformed their non-asthmatic rivals.It appears that years of intensive endurance training can provoke airway injury, AHR and asthma in athletes without any past history of asthma. Although further research is needed, it appears that these consequences of airway injury may abate in some athletes after they have ceased intensive training. The World Anti-Doping Code (the Code) has not prevented asthmatic individuals from becoming elite athletes. This review examines those sections of the Code that are relevant to respiratory physicians who manage elite and sub-elite athletes with asthma. The restrictions that the Code places or may place on the prescription of drugs to prevent and treat asthma in athletes are discussed. In addition, the means by which respiratory physicians are able to treat their elite asthmatic athlete patients with drugs that are prohibited in sport are outlined, along with some of the pitfalls in such management and how best to prevent or minimise them.

Predictors of airway hyperresponsiveness in elite athletes

INTRODUCTION

Elite athletes frequently experience asthma and airway hyperresponsiveness (AHR). We aimed to investigate predictors of airway pathophysiology in a group of unselected elite summer-sport athletes, training for the summer 2008 Olympic Games, including markers of airway inflammation, systemic inflammation, and training intensity.

METHODS

Fifty-seven Danish elite summer-sport athletes with and without asthma symptoms all gave a blood sample for measurements of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α), completed a respiratory questionnaire, and underwent spirometry. Bronchial challenges with mannitol were performed in all 57 athletes, and 47 agreed to perform an additional methacholine provocation.

RESULTS

Based on a physician's diagnosis, 18 (32%) athletes were concluded to be asthmatic. Asthmatic subjects trained more hours per week than the 39 nonasthmatics (median (min-max): 25 h·wk (14-30) versus 20 h·wk (11-30), P = 0.001). AHR to both methacholine and mannitol (dose response slope) increased with the number of weekly training h (r = 0.43, P = 0.003, and r = 0.28, P = 0.034, respectively). Serum levels of IL-6, IL-8, TNF-α, and hs-CRP were similar between asthmatics and nonasthmatics. However, there was a positive association between the degree of AHR to methacholine and serum levels of TNF-α (r = 0.36, P = 0.04). Fifteen out of 18 asthmatic athletes were challenged with both agents. In these subjects, no association was found between the levels of AHR to mannitol and methacholine (r = 0.032, P = 0.91).

CONCLUSION

AHR in elite athletes is related to the amount of weekly training and the level of serum TNF-α. No association was found between the level of AHR to mannitol and methacholine in the asthmatic athletes.

Dermatological conditions of aquatic athletes

Numerous manuscripts have described dermatologic conditions commonly seen in swimmers. This review provides an update on water dermatoses and discusses newly described conditions such as allergic contact dermatitis to chemical ingredients like potassium peroxymonosulate in pool water. In order to organize water related skin conditions, we have divided the skin conditions into a number of categories. The categories described include infectious and organism-related dermatoses, irritant and allergic dermatoses, and sun-induced dermatoses. The vast majority of skin conditions involving the water athlete result from chemicals and bacteria in the differing aquatic environments. When considering the effects of swimming on the skin, it is also useful to differentiate between exposure to freshwater (lakes, ponds and swimming pools) and exposure to saltwater. The risk of melanoma amongst swimmers is increased, and the use of SPF 30 or greater sunscreen and protective clothing is highly recommended. Swimmers should be reminded to generously apply sunscreen and be instructed on proper sunscreen usage. This review will serve as a guide for dermatologists, athletes, coaches, and other medical professionals in recognition and treatment of these conditions. We also intend for this review to provide dermatologist with a basic framework for the diagnosis and treatment of a few rarely described dermatological conditions in swimmers.