Health effects of exposure to chlorination by-products in swimming pools

Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming pools (water ingestion, skin absorption, and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports, and recreational attendance) and identify the main recommendations and unmet needs for research in this area.

High incidence rate of asthma among elite endurance athletes: a prospective 4-year survey

Objective: The prevalence of asthma among elite endurance athletes is high, but less is known about the incidence of asthma among athletes. The aim of this study was to examine the incidence rate of physician-diagnosed asthma among elite endurance athletes.Method: An annual postal questionnaire was sent to an open prospective cohort of elite endurance athletes between 2011 and 2015. Athletes from Swedish National teams, students at universities with elite sport partnership, and pupils at Swedish National elite sport schools, competing in cross-country skiing, biathlon, ski orienteering, or orienteering were invited (n = 666). Incidence rate of physician-diagnosed asthma was calculated among those without asthma at baseline (n = 449). Risk factors for incident physician-diagnosed asthma were identified using a multivariate logistic regression analysis.Results: Response rate was 88.7% (n = 591) at baseline. The median age of participants was 17 (range 15-36) years at inclusion. The study population included 407 (69%) skiers and 184 (31%) orienteers. The prevalence of asthma at baseline was 23.9% (n = 141). Incidence rate (95% confidence interval [CI]) of physician-diagnosed asthma was 61.2 (45.7-80.3) per 1,000 person-years. Risk factors (odds ratio [OR (95% CI)]) for incident physician-diagnosed asthma were family history of asthma (1.97 [1.04-3.68]), being a skier (3.01 [1.42-7.21]), and wheezing without having a cold (4.15 [1.81-9.26]).Conclusion: The incidence rate of physician-diagnosed asthma is high among Swedish elite endurance athletes.

Pharmacologic Strategies for Exercise-Induced Bronchospasm with a Focus on Athletes

Exercise-induced bronchoconstriction (EIB) is the transient narrowing of the airways during and after exercise that occurs in response to increased ventilation in susceptible individuals. It occurs across the age spectrum in patients with underlying asthma and can occur in athletes without baseline asthma. The inflammatory mechanisms underlying EIB in patients without asthma may be distinct from those underlying EIB in patients with asthma. This review summarizes mechanistic and clinical data that can guide the choice of chronic and acute pharmacologic therapies targeting control of EIB. Relevant regulations from the World Anti-Doping Agency are also discussed.

Exercise-Induced Bronchoconstriction: Background, Prevalence, and Sport Considerations

The transient airway narrowing that occurs as a result of exercise is defined as exercise-induced bronchoconstriction (EIB). The prevalence of EIB has been reported to be up to 90% in asthmatic patients, reflecting the level of disease control. However, EIB may develop even in subjects without clinical asthma, particularly in children, athletes, patients with atopy or rhinitis, and following respiratory infections. The intensity, duration, and type of training have been associated with the occurrence of EIB. In athletes, EIB seems to be only partly reversible, and exercise seems to be a causative factor of airway inflammation and symptoms.

Serum but not exhaled breath condensate periostin level is increased in competitive athletes

INTRODUCTION

Periostin is a matricellular protein expressed by many tissues. Its release may be enhanced, among others, through mechanical stimulation of muscles and bones as well as by cytokines of allergic inflammation.

OBJECTIVES

Our aim was to assess periostin levels in serum and exhaled breath condensate (EBC) of professional athletes, asthmatics and healthy controls. We also sought to determine whether acute treadmill exercise influences serum and EBC periostin.

METHODS

Study groups included 9 competitive swimmers, 10 mild-to-moderate asthmatics and 7 healthy controls. Athletes were assessed twice (in- and off-training period) while asthmatics and controls in one time-point. Data on demographics, allergy symptoms and exercise load were acquired through Allergy Questionnaire for Athletes (AQUA) and International Physical Activity Questionnaire (IPAQ). Serum and EBC were collected before and after treadmill exercise challenge.

RESULTS

Baseline serum periostin in swimmers during training period was significantly higher (5- to 7-fold) than in asthmatics (P = .01) and controls (P < .05). In EBC, lowest periostin levels were seen in athletes in-training as compared with off-training period (P < .01) and with asthmatics (P < .03). Acute bout of exercise did not induce significant changes neither in serum nor in EBC periostin in any group.

CONCLUSION

Increased serum, but not EBC, periostin levels in competitive athletes are probably because of permanently increased exercise load leading to stimulation, injury and regeneration of musculoskeletal tissues. Periostin may be considered marker of long-term exercise overload after confirmation in larger groups.

Mechanisms of exercise-induced bronchoconstriction in athletes: Current perspectives and future challenges

The evidence of exercise-induced bronchoconstriction (EIB) without asthma (EIBw_A ) occurring in athletes led to speculate about different endotypes inducing respiratory symptoms within athletes. Classical postulated mechanisms for bronchial obstruction in this population include the osmotic and the thermal hypotheses. More recently, the presence of epithelial injury and inflammation in the airways of athletes was demonstrated. In addition, neuronal activation has been suggested as a potential modulator of bronchoconstriction. Investigation of these emerging mechanisms is of major importance as EIB is a significant problem for both recreational and competitive athletes and is the most common chronic condition among Olympic athletes, with obvious implications for their competing performance, health and quality of life. Hereby, we summarize the latest achievements in this area and identify the current gaps of knowledge so that future research heads toward better defining the etiologic factors and mechanisms involved in development of EIB in elite athletes as well as essential aspects to ultimately propose preventive and therapeutic measures.

Swimming attendance during childhood and development of asthma: Meta-analysis

BACKGROUND

The association between asthma and swimming pool attendance has not been demonstrated and currently there are conflicting results. In order to clarify the association between asthma diagnosis in children and swimming pool attendance, and to assess the consistency of the available epidemiological studies, we completed a literature analysis on the relationship between the exposure to disinfection by-products in indoor swimming pools during childhood and asthma diagnosis.

METHODS

Following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria, a systematic review and meta-analysis was performed by searching MEDLINE via PubMed, TOXNET, and Scopus databases (from inception to 20 April 2015) using the key word "Asthma" together with "swimming pool", "disinfection by-products", "indoor air pollution" and "children". Inclusion criteria were: English language, a complete analytic study design involving a cohort of children (0-16 years), a well-defined definition of exposure, and the presence of data on effect and variance. Studies on in vivo, in vitro or professional and accidental exposure were excluded.

RESULTS

After a screening process, seven reports (n = 5851 subjects) were included out of a total of 2928 references. The reported OR of the association between swimming pool attendance and asthma prevalence ranged from 0.58 to 2.30. The present meta-analysis failed to identify a significant difference in asthma development between children attending swimming pools and controls (OR, 1.084; 95% CI: 0.89-1.31).

CONCLUSIONS

Swimming in childhood does not increase the likelihood of doctor-diagnosed asthma. Based on this meta-analysis review, the association of the disease with indoor pool attendance is still unclear.

Airway Hyperresponsiveness in Asthma: Measurement and Clinical Relevance

Airway hyperresponsiveness is a characteristic feature of asthma, and its measurement is an important tool in its diagnosis. With a few caveats, methacholine bronchial provocation by a 2-minute tidal breathing method is highly sensitive; a negative test result (PC₂₀ > 16 mg/mL, PD₂₀ > 400 μg) rules out current asthma with reasonable certainty. A PC₂₀ value of less than 1 mg/mL/PD₂₀ value of less than 25 μg is highly specific (ie, diagnostic) but quite insensitive for asthma. For accurate interpretation of the test results, it is important to control and standardize technical factors that have an impact on nebulizer performance. In addition to its utility to relate symptoms such as cough, wheeze, and shortness of breath to variable airflow obstruction (ie, to diagnose current asthma), the test is useful to make a number of other clinical assessments. These include (1) evaluation of patients with occupational asthma, (2) evaluation of patients with exercise-induced respiratory symptoms, (3) evaluation of novel asthma medications, (4) evaluation of relative potency of inhaled bronchodilators, (5) as a biomarker to adjust anti-inflammatory therapy to improve clinical outcomes, and (6) in the evaluation of patients with severe asthma to rule out masqueraders such as laryngeal dysfunction. The actual mechanism of altered smooth muscle behavior in asthma that is assessed by direct (eg, methacholine) or indirect (eg, allergen) bronchial provocation remains one of the most fundamental questions related to asthma that needs to be determined. The test is underutilized in clinical practice.

Exercise-induced bronchoconstriction update-2016

The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.

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.

Asthma prevalence in German Olympic athletes: A comparison of winter and summer sport disciplines

BACKGROUND

Prevalence of asthma in elite athletes shows very wide ranges. It remains unclear to what extent this is influenced by the competition season (winter vs. summer) or the ventilation rate achieved during competition. The aim of this study was to evaluate prevalence of asthma in German elite winter and summer athletes from a wide range of sport disciplines and to identify high risk groups.

METHODS

In total, 265 German elite winter athletes (response 77%) and 283 German elite summer athletes (response 64%) answered validated respiratory questionnaires. Using logistic regression, the asthma risks associated with competition season and ventilation rate during competition, respectively, were investigated. A subset of winter athletes was also examined for their FENO-levels and lung function.

RESULTS

With respect to all asthma outcomes, no association was found with the competition season. Regarding the ventilation rate, athletes in high ventilation sports were at increased risk of asthma, as compared to athletes in low ventilation sports (doctors' diagnosed asthma: OR 2.32, 95% CI 1.19-4.53; use of asthma medication: OR 4.46, 95% CI 1.52-13.10; current wheeze or use of asthma medication: OR 2.78, 95% CI 1.34-5.76). Athletes with doctors' diagnosed asthma were at an approximate four-fold risk of elevated FENO-values.

CONCLUSIONS

The clinically relevant finding of this study is that athletes' asthma seems to be more common in sports with high ventilation during competition, whereas the summer or winter season had no impact on the frequency of the disease. Among winter athletes, elevated FENO suggested suboptimal control of asthma.

Air quality and temperature effects on exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new-onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long-term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested.

Update on the Mechanisms of Pulmonary Inflammation and Oxidative Imbalance Induced by Exercise

The mechanisms involved in the generation of oxidative damage and lung inflammation induced by physical exercise are described. Changes in lung function induced by exercise involve cooling of the airways, fluid evaporation of the epithelial surface, increased contact with polluting substances, and activation of the local and systemic inflammatory response. The present work includes evidence obtained from the different types of exercise in terms of duration and intensity, the effect of both acute performance and chronic performance, and the influence of special conditions such as cold weather, high altitude, and polluted environments. Levels of prooxidants, antioxidants, oxidative damage to biomolecules, and cellularity, as well as levels of soluble mediators of the inflammatory response and its effects on tissues, are described in samples of lung origin. These samples include tissue homogenates, induced sputum, bronchoalveolar lavage fluid, biopsies, and exhaled breath condensate obtained in experimental protocols conducted on animal and human models. Finally, the need to simultaneously explore the oxidative/inflammatory parameters to establish the interrelation between them is highlighted.

Exercise and asthma: an overview

The terms 'exercise-induced asthma' (EIA) and 'exercise-induced bronchoconstriction' (EIB) are often used interchangeably to describe symptoms of asthma such as cough, wheeze, or dyspnoea provoked by vigorous physical activity. In this review, we refer to EIB as the bronchoconstrictive response and to EIA when bronchoconstriction is associated with asthma symptoms. EIB is a common occurrence for most of the asthmatic patients, but it also affects more than 10% of otherwise healthy individuals as shown by epidemiological studies. EIA and EIB have a high prevalence also in elite athletes, especially within endurance type of sports, and an athlete's asthma phenotype has been described. However, the occurrence in elite athletes shows that EIA/EIB, if correctly managed, may not impair physical activity and top sports performance. The pathogenic mechanisms of EIA/EIB classically involve both osmolar and vascular changes in the airways in addition to cooling of the airways with parasympathetic stimulation. Airways inflammation plays a fundamental role in EIA/EIB. Diagnosis and pharmacological management must be carefully performed, with particular consideration of current anti-doping regulations, when caring for athletes. Based on the demonstration that the inhaled asthma drugs do not improve performance in healthy athletes, the doping regulations are presently much less strict than previously. Some sports are at a higher asthma risk than others, probably due to a high environmental exposure while performing the sport, with swimming and chlorine exposure during swimming as one example. It is considered very important for the asthmatic child and adolescent to master EIA/EIB to be able to participate in physical activity on an equal level with their peers, and a precise early diagnosis with optimal treatment follow-up is vital in this aspect. In addition, surprising recent preliminary evidences offer new perspectives for moderate exercise as a potential therapeutic tool for asthmatics.

Two distinct phenotypes of asthma in elite athletes identified by latent class analysis

INTRODUCTION

Clusters of asthma in athletes have been insufficiently studied. Therefore, the present study aimed to characterize asthma phenotypes in elite athletes using latent class analysis (LCA) and to evaluate its association with the type of sport practiced.

METHODS

In the present cross-sectional study, an analysis of athletes' records was carried out in databases of the Portuguese National Anti-Doping Committee and the Norwegian School of Sport Sciences. Athletes with asthma, diagnosed according to criteria given by the International Olympic Committee, were included for LCA. Sports practiced were categorized into water, winter and other sports.

RESULTS

Of 324 files screened, 150 files belonged to asthmatic athletes (91 Portuguese; 59 Norwegian). LCA retrieved two clusters: "atopic asthma" defined by allergic sensitization, rhinitis and allergic co-morbidities and increased exhaled nitric oxide levels; and "sports asthma", defined by exercise-induced respiratory symptoms and airway hyperesponsiveness without allergic features. The risk of developing the phenotype "sports asthma" was significantly increased in athletes practicing water (OR = 2.87; 95% CI [1.82-4.51]) and winter (OR = 8.65; 95% CI [2.67-28.03]) sports, when compared with other athletes.

CONCLUSION

Two asthma phenotypes were identified in elite athletes: "atopic asthma" and "sports asthma". The type of sport practiced was associated with different phenotypes: water and winter sport athletes had three- and ninefold increased risk of "sports asthma". Recognizing different phenotypes is clinically relevant as it would lead to distinct targeted treatments.

Self-reported physician-diagnosed asthma among Swedish adolescent, adult and former elite endurance athletes

OBJECTIVE

Asthma is common among elite endurance athletes. Since the first published Swedish studies in 1993, awareness of "skiers' asthma" has increased. The current prevalence of asthma among Swedish skiers is unknown. This paper aims to present the design of a 5-year prospective annual questionnaire study on asthma among Swedish current and former elite endurance athletes, the first cross-sectional results on prevalence, age of onset, and predictors of self-reported physician-diagnosed asthma in the study population.

METHODS

An annual postal questionnaire is sent to Swedish elite skiers and orienteers during 2011-2015. In 2013, former Swedish Olympic skiers were similarly invited. We present cross-sectional data obtained in 2011 from the adolescents and adults and in 2013 from former skiers. A total of 491 athletes were invited. The results are presented by age, sex and sport. Chi-square test was used for group comparisons. Predictors of asthma were identified using logistic regression.

RESULTS

Response rate was 82%. Among athletes aged 15-19, 29% of the skiers (38% of the female skiers), and 17% of the orienteers reported asthma (p = 0.071). Among the athletes aged 20-34, 35% of the skiers and 16% of the orienteers reported asthma (p = 0.029). Among the former skiers aged 40-94, 22% reported asthma. Among the active athletes, the onset of asthma was in early adolescence. Logistic regression found increasing age, female sex, allergy, family history of allergy/asthma and being skier predictors of self-reported physician-diagnosed asthma.

CONCLUSIONS

The prevalence of physician-diagnosed asthma is high among Swedish endurance athletes, especially female adolescent skiers.

Exercise-induced bronchoconstriction: new evidence in pathogenesis, diagnosis and treatment

The acute airway narrowing that occurs as a result of exercise is defined exercise-induced bronchoconstriction (EIB). Most recent guidelines recommend distinguishing EIB with underlying clinical asthma (EIB_A) from the occurrence of bronchial obstruction in subjects without other symptoms and signs of asthma (EIBw_A). EIB has been in fact reported in up to 90 % of asthmatic patients, reflecting the level of disease control, but it may develop even in subjects without clinical asthma, particularly in children, athletes, patients with atopy or rhinitis and following respiratory infections. Both EIB_A and EIBw_A have peculiar pathogenic mechanisms, diagnostic criteria and responses to treatment and prevention. The use of biomarkers, proteomic approaches and innovative technological procedures will hopefully contribute to better define peculiar phenotypes and to clarify the role of EIB as risk factor for the development of asthma, as well as an occupational disease.

The role of sports and exercise in allergic disease: drawbacks and benefits

Although training and exercise have several benefits, overdoing it might not necessarily be a good thing. For instance, elite athletes have an increased risk for asthma and allergy. Several mechanisms can be implicated for this risk, which include the interplay between environmental training factors and athlete's personal risk factors, such as genetic susceptibility, neurogenic-mediated inflammation, and epithelial sensitivity. However, an overwhelming amount of scientific evidence shows the positive effects of sports as part of a healthy lifestyle. Training reduces breathlessness and asthma symptoms and attenuates Th2-mediated inflammatory responses. Taken together, the benefits far outweigh the potential hazards of training. An easily administered therapeutic healthy lifestyle intervention, which could be used alongside current treatment, must be developed.

Exercise-induced respiratory symptoms and allergy in elite athletes: Allergy and Asthma in Polish Olympic Athletes (A(2)POLO) project within GA(2)LEN initiative

INTRODUCTION

Exercise-induced respiratory symptoms are often reported by professional athletes, but asthma and allergy are underdiagnosed. Few studies used standardized questionnaires combined with clinical assessment to investigate asthma and allergy among athletes.

OBJECTIVES

Assessment of the prevalence of allergy and asthma symptoms among Polish professional athletes and confronting it with clinical data.

METHODS

Two hundred twenty-two Olympic athletes participated in the project being part of the Global Allergy and Asthma European Network (GA(2) LEN) Olympic study. Allergy and asthma status was determined using Allergy Questionnaire for Athletes (AQUA), spirometry, reversibility test, methacholine challenge and skin prick testing. Final diagnosis was established by an allergist.

RESULTS

At least one exercise-induced asthma (EIA) symptom was reported by 28.4% athletes, and finally asthma diagnosis was established in 11.3% while only 5.9% of athletes had history of asthma. Reversibility test was positive in 36% of athletes finally diagnosed with asthma. Allergic rhinitis (AR) symptoms were reported by 27%, and the diagnosis was confirmed in 21% of athletes while only 9% had previously diagnosed AR. No significant differences in frequency of asthma and AR were observed between endurance and non-endurance athletes.

CONCLUSIONS

High prevalence of exercise-induced respiratory symptoms among top athletes is not reflected by asthma diagnosis. As it was expected, our data confirm that - in diagnosis of EIA - lung function testing alone is not useful, whereas reversibility tests are of limited value.

Ventilation and respiratory mechanics

During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.

Airway dysfunction in elite athletes--an occupational lung disease?

Airway dysfunction is prevalent in elite endurance athletes and when left untreated may impact upon both health and performance. There is now concern that the intensity of hyperpnoea necessitated by exercise at an elite level may be detrimental for an athlete's respiratory health. This article addresses the evidence of causality in this context with the aim of specifically addressing whether airway dysfunction in elite athletes should be classified as an occupational lung disease. The approach used highlights a number of concerns and facilitates recommendations to ensure airway health is maintained and optimized in this population. We conclude that elite athletes should receive the same considerations for their airway health as others with potential and relevant occupational exposures.

Endurance exercise diverts the balance between Th17 cells and regulatory T cells

Endurance, marathon-type exertion is known to induce adverse changes in the immune system. Increased airway hyper-responsiveness and airway inflammation are well documented in endurance athletes and endurance exercise is considered a major risk factor for asthma in elite athletes. Yet, the mechanisms underlying this phenomenon are still to be deduced. We studied the effect of strenuous endurance exercise (marathon and half-ironman triathlon) on CD4+ lymphocyte sub-populations and on the balance between effector and regulatory CD4+ lymphocytes in the peripheral blood of trained athletes, Endurance exercise induced a significant increase in Th17 cells and a sustained decrease in peripheral blood regulatory T cells (Tregs). While interleukin (IL)-2 levels remained undetectable, post-race serum IL-6 and transforming growth factor (TGF) β levels were significantly elevated. Treg levels in sedentary controls' decreased in vitro after incubation with athletes' post-exercise serum, an effect that was attenuated by supplements of IL-2 or anti IL-6 neutralizing antibodies. Our data suggest that exercise-induced changes in serum cytokine levels promote alterations in Tregs and Th17 cell populations, which may divert the subtle balance in the immune system towards inflammation. This may explain allergic and autoimmune phenomena previously reported in endurance athletes and contribute to our understanding of exercise-related asthma.

Effect of physical training on airway inflammation in bronchial asthma: a systematic review

Background

The majority of the global population cannot afford existing asthma pharmacotherapy. Physical training as an airway anti-inflammatory therapy for asthma could potentially be a non-invasive, easily available, affordable, and healthy treatment modality. However, effects of physical training on airway inflammation in asthma are currently inconclusive. The main objective of this review is to summarize the effects of physical training on airway inflammation in asthmatics.

Methods

A peer reviewed search was applied to Medline, Embase, Web of Science, Cochrane, and DARE databases. We included all observational epidemiological research studies and RCTs. Studies evaluating at least one marker of airway inflammation in asthmatics after a period of physical training were selected. Data extraction was performed in a blinded fashion. We decided a priori to avoid pooling of the data in anticipation of heterogeneity of the studies, specifically heterogeneity of airway inflammatory markers studied as outcome measures.

Results

From the initial 2635 studies; 23 studies (16 RCTs and 7 prospective cohort studies) were included. Study sizes were generally small (median sample size = 30). There was a reduction in C-reactive protein, malondialdehyde, nitric oxide, sputum cell counts and IgE in asthmatics with physical training. Mixed results were observed after training for fractional excretion of nitric oxide and bronchial hyperresponsiveness. The data was not pooled owing to significant heterogeneity between studies, and a funnel plot tests for publication bias were not performed because there were less than 10 studies for almost all outcome measures. Physical training intervention type, duration, intensity, frequency, primary outcome measures, methods of assessing outcome measures, and study designs were heterogeneous.

Conclusion

Due to reporting issues, lack of information and heterogeneity there was no definite conclusion; however, some findings suggest physical training may reduce airway inflammation in asthmatics.

Are former athletes more prone to asthma?

OBJECTIVE

We have designed the present study to compare prevalent lifetime cases of diagnosed asthma or exercise-induced asthma, as well as current related respiratory symptoms, across two different levels of former athletes and non-athletes.

METHODS

Demographic, behavioral, and asthma history information, as well as current related respiratory symptoms, were obtained through a questionnaire from 627 subjects (290 former elite and 201 non-elite athletes that competed between 1969 and 2005, and 136 control subjects that had never been athletes).

RESULTS

Non-athletes presented a higher percentage of subjects reporting the existence of symptoms associated with exercise or vigorous activities. Former athletes who reported having practiced mostly in indoor facilities presented significant lower risk for asthma than outdoor athletes (Odds Ratio = 0.48, 95% CI = 0.25-0.94). Multiple regression analysis (where "B" refers to unstandardized coefficients) showed that former elite (B = -0.85, p < .001) and non-elite athletes (B = -0.70, p < .001) were less prone to be affected by asthma-related symptoms than non-athletes. Athletes with careers that lasted more than 20 years were more likely to possess asthma-related symptoms than the ones with shorter careers (3-7 years, B = -0.47, p < .001; 8-14 years, B = -0.42, p < .01; 15-20, B = -0.32, p < .05).

CONCLUSIONS

Non-athletes seem to have a higher prevalence of respiratory symptoms. Among former athletes, career characteristics seem to play a crucial role, with special emphasis to its duration, where the most lengthy seem to be more associated with respiratory symptoms.

Exhaled nitric oxide indicates poorly athlete's asthma

INTRODUCTION

In athletes, exercise-induced respiratory symptoms are common and their assessment is time and resource consuming.

OBJECTIVE

The objective was to evaluate fractional concentration of exhaled nitric oxide (FENO) as a predictor of bronchial hyperresponsiveness (BHR) and of asthma.

MATERIALS AND METHODS

Eighty-seven elite athletes and a control group of 87 sedentary patients with symptoms suggesting asthma underwent measurements of FENO and of BHR by using methacholine provocation test (MCH) and eucapnic voluntary hyperpnoea (EVH) (athletes) or histamine provocation test (HIST) (controls).

RESULTS

In athletes, elevated FENO (>30 ppb) was not associated with lung function-confirmed asthma or with MCH positivity, but receiver operating characteristics (ROC) analysis showed some predictive value for EVH positivity [Area Under Curve (AUC) 0.652, 95% confidence interval (CI): 0.53 to 0.78, P = 0.020]. However, the sensitivity (55%) and the specificity (71%) were poor. In sedentary patients, FENO was significantly associated with both confirmed asthma and HIST positivity, ROC analysis showing FENO to be significantly predictive for HIST positivity (AUC 0.83, 95% CI: 0.70 to 0.96, P = 0.001) and for asthma (AUC 0.74, 95% CI: 0.63 to 0.85, P < 0.001).

CONCLUSION

The results suggest that in contrast to sedentary patients, FENO seems to be a poor predictor of BHR and of clinical asthma in elite athletes. We find it unlikely that FENO could be a useful screening tool in athletes with exercise-induced respiratory symptoms.

Asthma medication is increasingly prescribed for finnish olympic athletes--for a reason?

BACKGROUND

Use of asthma medication is common among athletes. In 2009, the World Anti-Doping Committee (WADA) and the International Olympic Committee removed the need to document asthma by lung function tests before the use of inhaled β2-agonists.

METHODS

We assessed the changes in asthma medication use in Finnish Olympic athletes 8 years apart in 2002 (N = 446) and 2009 (N = 372). The athletes filled out a questionnaire on asthma symptoms, diagnosis, and medication.

RESULTS

The use of asthma medication increased from 9.4% in 2002 to 12.6% in 2009 (adjusted odds ratio (OR) = 1.71, 95% confidence interval (CI) 1.08-2.69). Fixed combinations of inhaled long-acting β2-agonists (LABAs) and inhaled corticosteroids (ICSs) were used three times more in 2009 vs. 2002 (OR = 3.38, 95% CI 1.26-9.12). At the same time, no significant changes were observed in the occurrences of physician-diagnosed asthma (13.9% vs. 15.9%) or wheezing (10.3% vs. 10.2%). In 2002, all athletes on asthma medication also had a physician-diagnosed disease, but in 2009, 11.8% of the athletes on medication were lacking it.

CONCLUSIONS

Especially, the use of combination therapy of LABAs and ICSs is increasing among Finnish Olympic athletes. This trend is worrying as it is not based on increasing occurrence of symptoms, asthma diagnoses, or objective lung function measurements. More data, also from other countries, are needed to change recommendations or WADA rules.

Mechanisms and management of exercise-induced asthma in elite athletes

OBJECTIVE AND METHODS

Asthma is often reported by elite athletes, especially endurance athletes. The aim of this article is to review current knowledge of mechanisms and management of exercise-induced asthma (EIA) in adult elite athletes.

RESULTS

The mechanisms underlying EIA is incompletely understood, but the two prevailing hypotheses are the hyper-osmolarity and the thermal hypothesis. Both hypotheses consider inflammation and activation of mast cells as being crucial for the development of EIA, although the assumed mechanisms triggering the inflammatory response differ. Objective testing is of utmost importance in the diagnosis of EIA in elite athletes. Management of EIA can be divided into pharmacologic and non-pharmacologic treatment. The basic principles for the treatment of EIA in elite athletes should be as for any asthmatic individual, including use of inhaled corticosteroids (ICS), β(2)-agonists, and leukotriene antagonists. However, evidence suggests that daily use of β(2)-agonists might lead to the development of tolerance. ICS therapy is, due to its anti-inflammatory effects, the recommended primary therapy for EIA also in elite athletes. All doctors treating individuals with asthma, especially elite athletes, should remain updated on doping aspects of asthma therapy. Non-pharmacologic management of EIA in elite athletes includes physical warm-up, which takes advantage of the refractory period following an attack of EIA, whereas high intake of antioxidants may reduce airway inflammation. Wearing heat masks, specially designed for outdoor winter athletes, might protect against bronchoconstriction triggered by inhalation of cold and dry air.

CONCLUSION

EIA in elite athletes should be managed as in any individual with asthma, but the risk of developing tolerance to bronchodilators as well as doping aspects should always be taken into account.

Asthma in elite athletes

Asthma is frequently found among elite athletes performing endurance sports such as swimming, rowing and cross-country skiing. Although these athletes often report symptoms while exercising, they seldom have symptoms at rest. Moreover, compared with nonathletic asthmatic individuals, elite athletes have been shown to have a different distribution of airway inflammation and unequal response to bronchial provocative test. Elite athletes display signs of exercise-induced symptoms, for example, nonasthmatic inspiratory wheeze, vocal cord dysfunction and cardiac arrhythmias, which could limit their physical capacity. Elite athletes should undergo comprehensive assessment to confirm an asthma diagnosis and determine its degree of severity. Treatment should be as for any other asthmatic individual, including the use of β2-agonist, inhaled steroid as well as leukotriene-antagonist. It should, however, be noted that daily use of β-agonists could expose elite athletes to the risk of developing tolerance towards these drugs. Use of β2-agonist should be replaced with daily inhaled corticosteroid treatment, the most important treatment of exercise-induced asthma. All physicians treating asthma should be aware of the doping aspects. Systemic β2-agonist intake is strictly prohibited, whereas inhaled treatment is allowed in therapeutic doses when asthma is documented and dispensation has been granted when needed.

Lifestyle and the Respiratory Health of Children

This article offers a review of the potential influences of personal lifestyle on respiratory health in children, looking at both healthy individuals and those with respiratory disorders. As with many aspects of health, regular physical activity, an appropriate diet, and avoidance of obesity and cigarette smoke all contribute to optimal development of the healthy child. An active lifestyle is associated with greater static and dynamic lung volumes, greater efficiency of the ventilatory process, and an optimization of breathing patterns. The risk of upper respiratory infections is also reduced in those maintaining a moderate level of physical activity. Maternal smoking during pregnancy, as well as active and passive smoking, all have an adverse influence on lung function in the child, the largest effects being on dynamic lung volumes. The risk of developing asthma seems reduced in children who maintain a normal body mass and are physically active. A program of graded physical activity is of therapeutic value in a number of established respiratory conditions, including asthma, cystic fibrosis, and ventilatory impairment from neuromuscular disorders. Exercise carries a slight risk of fatalities from asthma and anaphylactic reactions. In designing an optimal physical activity program, it is also important to guard against the hazards of deep oronasal breathing, including the precipitation of bronchospasm by the inhalation of cold, dry air and pollens; an increased exposure to atmospheric pollutants (reducing and oxidant smog, fine and ultra-fine particulates, and carbon monoxide); and possible long-term dangers from chlorine derivatives in the atmosphere of indoor swimming pools.

Asthma in swimmers: a review of the current literature

Asthma is common in many types of athletes, but its prevalence appears to be particularly high in swimmers. Long-term and acute exposure to swimming pool disinfectants has been shown to increase asthma risk in swimmers through inducing oxidative stress, which results in inflammation of the pulmonary epithelium and subsequent airway remodeling. Individuals with specific genotypes are more likely to develop asthma when exposed to inhaled irritants. Therefore, it is important for physicians to be knowledgeable about the risks associated with asthma in swimmers, as well as the diagnostic techniques and practices to reduce asthma symptoms.

Swimming and asthma: factors underlying respiratory symptoms in competitive swimmers

BACKGROUND

Swimming is recommended for asthmatics. However, many competitive swimmers report asthmatic symptoms. While some studies identify the swimming environment as a trigger for allergy and asthmatic symptoms, even more studies suggest swimming to be suitable for people with allergies and asthma. The factors behind the symptoms were studied first by determining the prevalence of asthma, allergy and self-reported asthmatic symptoms in experienced Finnish swimmers and then by examining the relationships between the reported symptoms and the main triggering factors: medical history, environment and exercise intensity.

MATERIALS AND METHODS

Top swimmers (n = 332) of the Finnish Swimming Association registry (N = 4578) were asked to complete a structured questionnaire on their medical history, swimming background, swimming environment and symptoms in different swimming intensities. Two hundred experienced swimmers, 107 females and 93 males, with an average age of 18.5 [standard deviation (SD) = 3.0] years and a swimming training history of 9 (SD = 3.8) years completed the questionnaire.

RESULTS

Physician-diagnosed asthma was reported by 32 swimmers (16%), including 24 (12%) with exercise-induced asthma. Physician-diagnosed allergy was reported by 81 (41%) swimmers. Asthmatic symptoms during swimming were described by 84 subjects (42%). Most symptoms occurred when swimming exceeded speeds corresponding to the lactic/anaerobic threshold. Family history of asthma was significant and the most important risk factor for asthmatic symptoms.

CONCLUSIONS

The prevalence of asthma in swimmers was higher than in the general population but not different from that in other endurance athletes. Family history of asthma and increased swimming intensity had the strongest associations with the reported asthmatic symptoms.

Effects of chlorine and exercise on the unified airway in adolescent elite Scottish swimmers

BACKGROUND

Chlorine metabolites and high training load may produce exercise-induced bronchospasm (EIB) in elite swimmers. The aim of this study was to assess the combined effects of chlorine and exercise on the unified airway of adolescent elite swimmers.

METHODS

The Scottish Midlands District squad were assessed during an indoor pool session at the National Swimming Academy. Athletes trained at least 8 h per week. Subjects underwent tidal (T(NO)) and nasal (N(NO)) exhaled NO and peak nasal inspiratory flow (PNIF) pre and post a 2 h session. A physiological exercise challenge assessed EIB in n = 36 swimmers (>10% fall in forced expiratory volume in 1 s (FEV(1))).

RESULTS

Combined and free chlorine levels (mg/l) were 1.66 and 0.3 respectively. n = 36 swimmers (mean age 13.3 years) were assessed: n = 8 (22%) had known asthma; n = 13 (36%) had a positive physiological challenge; 18 (50%) complained of symptoms suggestive of EIB. n = 10/28 (36%) who did not have asthma were found to have a positive exercise challenge. There was no significant association between reported exercise symptoms and positive exercise test. There was no significant change in T(NO) or N(NO) for pre vs postexposure, irrespective of asthma diagnosis or AHR. n = 15 (42%) swimmers complained of worsening nasal symptoms postexposure, but only n = 7 (14%) had a demonstrable fall in PNIF (mean 33 l/min). No significant association was found between PNIF and symptoms.

CONCLUSIONS

Combined exposure to chlorine and exercise did not affect surrogate markers of inflammation in the unified airway. There was a high prevalence of undiagnosed EIB.

An update on exercise-induced bronchoconstriction with and without asthma

Exercise-induced bronchoconstriction (EIB) is defined as transient, reversible bronchoconstriction that develops after strenuous exercise. It is a heterogeneous syndrome made up of a spectrum of phenotypes ranging from the asymptomatic military recruit whose condition is detected by diagnostic exercise challenge to the athlete with known asthma to the elite athlete for whom EIB represents an overuse or injury syndrome. If exercise is the only identified trigger for bronchoconstriction, it is called EIB. However, when it is associated with known asthma, then it is defined as EIB with asthma. This review discusses the pathogenesis, presentation, diagnosis, and management of EIB and EIB with asthma.

Impact of chlorinated swimming pool attendance on the respiratory health of adolescents

OBJECTIVE

The goal was to estimate the burden of allergic diseases associated with chlorinated pool exposure among adolescents.

METHODS

We examined 847 students, 13 to 18 years of age, who had attended outdoor or indoor chlorinated pools at various rates. Of them, 114 had attended mainly a copper-silver pool and served as a reference group. We measured total and aeroallergen-specific immunoglobulin E (IgE) levels in serum and screened for exercise-induced bronchoconstriction. Outcomes were respiratory symptoms, hay fever, allergic rhinitis, and asthma that had been diagnosed at any time (ever asthma) or was being treated with medication and/or was associated with exercise-induced bronchoconstriction (current asthma).

RESULTS

Among adolescents with atopy with serum IgE levels of>30 kIU/L or aeroallergen-specific IgE, the odds ratios (ORs) for asthma symptoms and for ever or current asthma increased with the lifetime number of hours spent in chlorinated pools, reaching values of 7.1 to 14.9 when chlorinated pool attendance exceeded 1000 hours. Adolescents with atopy with chlorinated pool attendance of >100 hours had greater risk of hay fever (OR: 3.3-6.6), and those with attendance of >1000 hours had greater risk of allergic rhinitis (OR: 2.2-3.5). Such associations were not found among adolescents without atopy or with copper-silver pool attendance. The population attributable risks for chlorinated pool-related ever-diagnosed asthma, hay fever, and allergic rhinitis were 63.4%, 62.1%, and 35.0%, respectively.

CONCLUSION

Chlorinated pool exposure exerts an adjuvant effect on atopy that seems to contribute significantly to the burden of asthma and respiratory allergies among adolescents.

The respiratory health of swimmers

Regular physical activity is recognized as an effective health promotion measure. Among various activities, swimming is preferred by a large portion of the population. Although swimming is generally beneficial to a person's overall health, recent data suggest that it may also sometimes have detrimental effects on the respiratory system. Chemicals resulting from the interaction between chlorine and organic matter may be irritating to the respiratory tract and induce upper and lower respiratory symptoms, particularly in children, lifeguards and high-level swimmers. The prevalence of atopy, rhinitis, asthma and airway hyper-responsiveness is increased in elite swimmers compared with the general population. This may be related to the airway epithelial damage and increased nasal and lung permeability caused by the exposure to chlorine subproducts in indoor swimming pools, in association with airway inflammatory and remodelling processes. Currently, the recommended management of swimmers' respiratory disorders is similar to that of the general population, apart from the specific rules for the use of medications in elite athletes. Further studies are needed to better understand the mechanisms related to the development or worsening of respiratory disorders in recreational or competitive swimmers, to determine how we can optimize treatment and possibly help prevent the development of asthma.

Childhood asthma and environmental exposures at swimming pools: state of the science and research recommendations

OBJECTIVES

Recent studies have explored the potential for swimming pool disinfection by-products (DBPs), which are respiratory irritants, to cause asthma in young children. Here we describe the state of the science on methods for understanding children's exposure to DBPs and biologics at swimming pools and associations with new-onset childhood asthma and recommend a research agenda to improve our understanding of this issue.

DATA SOURCES

A workshop was held in Leuven, Belgium, 21-23 August 2007, to evaluate the literature and to develop a research agenda to better understand children's exposures in the swimming pool environment and their potential associations with new-onset asthma. Participants, including clinicians, epidemiologists, exposure scientists, pool operations experts, and chemists, reviewed the literature, prepared background summaries, and held extensive discussions on the relevant published studies, knowledge of asthma characterization and exposures at swimming pools, and epidemiologic study designs.

SYNTHESIS

Childhood swimming and new-onset childhood asthma have clear implications for public health. If attendance at indoor pools increases risk of childhood asthma, then concerns are warranted and action is necessary. If there is no such relationship, these concerns could unnecessarily deter children from indoor swimming and/or compromise water disinfection.

CONCLUSIONS

Current evidence of an association between childhood swimming and new-onset asthma is suggestive but not conclusive. Important data gaps need to be filled, particularly in exposure assessment and characterization of asthma in the very young. Participants recommended that additional evaluations using a multidisciplinary approach are needed to determine whether a clear association exists.

Exercise-induced bronchoconstriction and atopy in Tunisian athletes

Background

This study is a cross sectional analysis, aiming to evaluate if atopy is as a risk factor for exercise induced bronchoconstriction (EIB) among Tunisian athletes.

Methods

Atopy was defined by a skin prick test result and EIB was defined as a decrease of at least 15% in forced expiratory volume in one second (FEV1) after 8-min running at 80–85% HRmaxTheo. The study population was composed of 326 athletes (age: 20.8 ± 2.7 yrs – mean ± SD; 138 women and 188 men) of whom 107 were elite athletes.

Results

Atopy was found in 26.9% (88/326) of the athletes. Post exercise spirometry revealed the presence of EIB in 9.8% of the athletes including 13% of the elite athletes. Frequency of atopy in athletes with EIB was significantly higher than in athletes without EIB [62.5% vs 23.1%, respectively].

Conclusion

This study showed that atopic Tunisian athletes presented a higher risk of developing exercise induced bronchoconstriction than non-atopic athletes.

Swimming pool, respiratory health, and childhood asthma: should we change our beliefs?

Swimming is often recommended as a sport because of its several benefits to health. It is also recommended in asthmatic children as a sport with a lower potential for prompting exercise-induced asthma. However, there is growing interest in the potentially harmful effects of repeated respiratory tract exposure to chlorinated products and the problem of possible swimming-related health hazards is gaining importance at international level. It is already known that acute exposure to chlorine gas as in swimming pool accidents causes lung damage and also that elite swimmers may have increased airway inflammation and bronchial hyperreactivity, probably as a result of repeated exposure to chlorine derivatives. Recently some studies have been conducted to investigate whether repeated exposure to chlorine by-products in recreational swimmers might also lead to lung damage. In addition, some studies have been lately published on the even more debated issue of the possible harmful effects of baby swimming on respiratory health. This article reviews and discusses data from the literature on the effects of chlorine derivatives in different categories of people routinely attending swimming pools. The need for longitudinal studies is emphasized to definitely clarify any role of chlorinated swimming pool attendance in the development of asthma in recreational swimmers.

Use of prescription drugs in athletes

Although athletes are young and generally healthy, they use a variety of non-doping classified medicines to treat injuries, cure illnesses and obtain a competitive edge. Athletes and sports medicine physicians try to optimize the treatment of symptoms related to extreme training during an elite athlete's active career. According to several studies, the use of antiasthmatic medication is more frequent among elite athletes than in the general population. The type of training and the kind of sport influence the prevalence of asthma. Asthma is most common among those competing in endurance events, such as cycling, swimming, cross-country skiing and long-distance running. Recent studies show that athletes use also NSAIDs and oral antibacterials more commonly than age-matched controls, especially athletes competing in speed and power sports. Inappropriately high doses and concomitant use of several different NSAIDs has been observed. All medicines have adverse effects that may have deleterious effects on elite athletes' performance. Thus, any unnecessary medication use should be minimized in elite athletes. Inhaled beta(2)-agonists may cause tachycardia and muscle tremor, which are especially harmful in events requiring accuracy and a steady hand. In experimental animal models of acute injury, especially selective cyclo-oxygenase-2 inhibitors have been shown to be detrimental to tissue-level repair. They have been shown to impair mechanical strength return following acute injury to bone, ligament and tendon. This may have clinical implications for future injury susceptibility. However, it should be noted that the current animal studies have limited translation to the clinical setting. Adverse effects related to the CNS and gastrointestinal adverse reactions are commonly reported in connection with NSAID use also in elite athletes. In addition to the potential for adverse effects, recent studies have shown that NSAID use may negatively regulate muscle growth by inhibiting protein synthesis. Physicians and pharmacists taking care of athletes' medication need to be aware of the medicines that an athlete is taking and how those medicines interact with performance, exercise, environment and other medicines. Sport associations should repeatedly monitor not only the use of banned substances, but also the trends of use of legal medicines in athletes. Not only physicians and pharmacists, but also athletes and coaches should be better educated with respect to potential benefits and risks, and how each agent may affect an athlete's performance. The attitudes and beliefs leading to ample use of legal medicines in athletes is an interesting area of future research.

Interpretation of the "positive" methacholine challenge

BACKGROUND

A methacholine challenge may be used in confirming the diagnosis of asthma, occupational asthma, or reactive airways dysfunction syndrome (RADS) through identification of bronchial hyperreactivity (BHR). While sensitivity of the test in diagnosing clinically significant asthma is excellent, specificity of the test is poor. Since there are many conditions which have been associated with BHR, a positive test must be interpreted cautiously.

METHODS

This paper reviews potential causes of a positive methacholine challenge other than asthma or RADS which have been reported in the medical literature.

RESULTS

Factors which may be associated with a positive methacholine test include test methodology, normal variation of BHR in the general population, and numerous medical conditions.

CONCLUSIONS

In cases of inhalation exposure evaluations, alternative explanations must be considered when determining whether a causal association exists between the exposure and a positive methacholine test result.

Chinese response to allergy and asthma in Olympic athletes

China is going to host the Games of the XXIX Olympiad from 8-24 August 2008 in Beijing. The number of athletes and accompanying individuals expected to arrive at China for the Beijing Olympics is estimated at over 10 000 and among them at least 2 000 (20%) are suspected to suffer from respiratory allergies. It is important to monitor the pollen counts and improve air quality in Beijing because Olympic athletes would be exposed to airborne allergens and pollutants during competitions which could hinder peak performance. The main pollen and spore families in Beijing are Artemisia, Ambrosia, Chenopodiaceae and Gramineae. They can reach around 307 000 grains of pollen/1000 m(3) of air in August. Economic development in China is usually linked with worsening of air quality. Due to the adoption of various control measures, the ambient air quality in a number of areas in Beijing has actually improved. The ambient air TSP and SO(2) levels in Beijing have been decreasing in the last decade. However, ambient air NO(x) level has been increasing due to the increased number of motor vehicles. Nevertheless, dedicated medical facilities in Beijing will provide medical services to athletes and delegations from all over the world during the Beijing Olympic Games.

Exercise-induced hypersensitivity syndromes in recreational and competitive athletes: a PRACTALL consensus report (what the general practitioner should know about sports and allergy)

Exercise-induced (EI) hypersensitivity disorders are significant problems for both recreational and competitive athletes. These include EI-asthma, EI-bronchoconstriction, EI-rhinitis, EI-anaphylaxis and EI-urticaria. A group of experts from the European Academy of Allergology and Clinical Immunology and the American Academy of Allergy Asthma and Immunology met to discuss the pathogenesis of these disorders and how to diagnose and treat them, and then to develop a consensus report. Key words (exercise with asthma, bronchoconstriction, rhinitis, urticaria or anaphylaxis) were used to search Medline, the Cochrane database and related websites through February 2008 to obtain pertinent information which, along with personal reference databases and institutional experience with these disorders, were used to develop this report. The goal is to provide physicians with guidance in the diagnosis, understanding and management of EI-hypersensitivity disorders to enable their patients to safely return to exercise-related activities.

The effects of lifestyle intervention for hypertension on low back pain: a randomized controlled trial

STUDY DESIGN

Randomized controlled trial.

OBJECTIVE

To assess the effects of a lifestyle intervention for hypertension on low back pain.

SUMMARY OF BACKGROUND DATA

According to prospective etiologic studies, a causal association exists between certain lifestyle factors and low back pain. These factors are similar to those that elevate the risk for hypertension. Nevertheless, no randomized controlled trial has assessed effectiveness of lifestyle intervention for the treatment of hypertension on the prevalence of low back pain.

METHODS

A total of 731 hypertensive employees from 45 worksites were assigned to multidisciplinary lifestyle interventions for hypertension in a rehabilitation center or to routine care in occupational or primary healthcare services during 12 months. Questionnaire data on low back pain were used to assess the effects of the intervention on the extent of low back pain and disability.

RESULTS

The changes in prevalence and duration of low back pain, and related disability did not differ between the 2 groups, although there were favorable changes in some risk factors, such as body weight and physical inactivity. Subgroup analyses among patients with moderately heavy or heavy work showed that the prevalence of low back pain during the previous 12 months decreased more in the intervention than in the control group.

CONCLUSION

Multidisciplinary lifestyle intervention aimed to reduce hypertension is not effective at reducing prevalence of low back pain or disability. However, in the subgroup of persons doing moderate or heavy work, the intervention seemed to reduce prevalence of low back pain during the 1-year follow-up.

The determinants of prevalence of health complaints among young competitive swimmers

OBJECTIVES

Chloramines, which are produced by the reaction of chlorine with the organic matter present in indoor pools, are potential airway irritants in swimmers. The objective of this study was to compare the prevalence of health complaints of young swimmers and young indoor soccer players and to evaluate the relationship between chloramine concentrations and the athletes' health complaints.

METHODS

Health complaints were first (Part 1) documented by questionnaire in 305 competitive swimmers and 499 indoor soccer players of the Québec City region (Canada). Then, (Part 2) health complaints were documented during five training sessions in 72 competitive swimmers in comparison to 73 soccer players. The chloramines in the swimming pool air and water were measured as well as the peak expiratory flow (PEF) before and after the training session.

RESULTS

In Part 1, the swimmers reported more lower (adjusted OR: 1.5; IC95%= 1.0-2.2) and upper respiratory symptoms (adjusted OR: 3.7; IC95%= 2.4-5.8). In Part 2, the swimmers experienced more frequent lower (adjusted OR: 3.5; IC95%= 2.0-6.0) and upper respiratory symptoms (adjusted OR: 3.1; IC95%= 1.8-5.4). Overall, swimmers exposed to the highest levels of chloramines in the air and water had more respiratory complaints.

CONCLUSIONS

Swimmers exposed to chlorination by-products in both the water and air of indoor swimming pools experience frequent respiratory symptoms that could potentially be reduced by limiting exposure to these products.