The Prevalence of Asthma and Respiratory Symptoms among Cross-Country Skiers in Early Adolescence

Prevalence of Asthma among Norwegian Elite Athletes

Objective

Asthma is a common problem among elite athletes and represents a health risk interfering with the athlete's performance status. This study aimed to evaluate the asthma prevalence among Norwegian summer and winter elite athletes and asthma prevalence across sport categories. We also aimed to examine whether bronchial hyperresponsiveness (BHR), lung function, fraction of exhaled nitric oxide (FENO), and allergy status differed between asthmatic and non-asthmatic elite athletes.

Methods

Norwegian athletes qualifying for the Beijing Olympic Summer Games 2008 (n = 80) and the Vancouver Olympic Winter Games 2010 (n = 55) were included. The athletes underwent clinical respiratory examination including lung function measurement, methacholine bronchial challenge for assessment of BHR, FENO, and skin prick testing. Asthma was diagnosed based on respiratory symptoms and clinical examination including objective measurements.

Results

Asthma was more prevalent among winter athletes (50%) than summer athletes (20%). Thirty-three (52%) endurance athletes, 3 (6%) team sport athletes, and 7 (33%) technical sport athletes had medically diagnosed asthma. Significantly lower lung function (p < 0.001) and higher prevalence of severe BHR (p < 0.001) were found in asthmatic athletes compared with non-asthmatic athletes.

Conclusion

Asthma is common among Norwegian elite athletes, with winter and endurance athletes showing the highest prevalence. Asthmatic athletes were characterized by lower lung function and more severe BHR compared with non-asthmatic counterparts. The high prevalence among winter and endurance athletes demonstrates a need for increased attention to prevent and reduce the prevalence of asthma among those athletes.

High training volume is associated with increased prevalence of non-allergic asthma in competitive cross-country skiers

Background

Cross-country skiers have a high prevalence of asthma, but its phenotypes and association with success in competitions are not known.

Objective

To investigate, by means of a postal survey, the relative proportions of allergic and non-allergic asthma in competitive cross-country skiers compared with the general population, to study how performance level and training volume are related to asthma and its type and to assess the possible risk factors for allergic and non-allergic asthma in competitive skiers.

Methods

All Finnish cross-country skiers enrolled in the largest national competitions in winter 2019 (n=1282), and a random sample (n=1754) of the general population of the same age were sent a postal questionnaire. The response rate was 27.4% (n=351) for skiers and 19.5% (n=338) for the controls. International Ski Federation (FIS) ranking points measured the level of success in skiers. Asthma was defined as self-reported, physician-diagnosed asthma. Asthma was considered allergic if associated with doctor-diagnosed allergy, and exposure to allergens provoked asthma symptoms.

Results

The prevalence of asthma was higher in skiers than in the controls (25.9% vs 9.2%, p<0.001), and it was the highest (56.1%) in the most successful quartile of skiers. Asthma was more often non-allergic in skiers than in the controls (60.1% vs 38.7%, p=0.036). Being a skier came with a higher risk for non-allergic (OR 5.05, 95% CI 2.65 to 9.61) than allergic asthma (OR 1.92, 1.08–3.42). Using multivariable regression analysis, training volume was associated with non-allergic asthma, while age, family history of asthma and allergic rhinitis were associated with allergic asthma.

Conclusion

The prevalence of asthma is the highest in the most successful cross-country skiers. The asthma in skiers is mostly non-allergic compared with the general population of the same age. The most important risk factor for non-allergic asthma in skiers is high training volume.

Higher prevalence but later age at onset of asthma in cross-country skiers compared with general population

Cross-country skiing causes strain in the airways because skiers train and compete in cold air. The aim of this survey was to investigate the prevalence and age at onset of asthma, asthma control, and use of asthma medication in Finnish competitive cross-country skiers. All cross-country skiers who were enrolled in the largest national competitions in winter 2019 (n = 1282) were invited to the study via the Finnish Ski Association. A control group (n = 1733) was matched for the responding skiers by age, gender, and region. The response rate was 27.4% (n = 351) for skiers and 19.5% (n = 338) for the controls. The prevalence of asthma was 25.9% in skiers and 9.2% in the controls (p < 0.001). Median (IQR) age at first asthma-related symptoms was higher in skiers than in the controls (13.0 (8.25-16.0) vs. 8.0 (2.25-11.75) years, p < 0.001), and the difference in asthma prevalence was evident only after the start of skiing career. Median (IQR) Asthma Control Test (ACT) score in skiers and controls with asthma was 22.0 (21-24) vs. 22.0 (19-24) (p = 0.611), and 89.0% of skiers and 77.4% of controls had well-controlled asthma (ACT score ≥20). In skiers with asthma, 82.4% used regular inhaled corticosteroids (ICS), and 80.2% used bronchodilators. A fixed combination of ICS +long-acting β2-agonist was regularly used by 47.3% of the skiers and 22.6% of the controls with asthma (p = 0.016). In conclusion, asthma prevalence is about 2.5 times higher, and age at onset of asthma is later in skiers compared with the controls. Asthma in cross-country skiers is mostly well controlled and on regular maintenance treatment.

Management of Intermittent and Persistent Asthma in Adolescent and High School Athletes

Asthma is the most common chronic condition during childhood and adolescence, affecting an estimated 8% of children and youngsters below 18 years in the United States and the United Kingdom. In adolescent athletes, asthma-like symptoms may represent a common consequence of regular sport practice. Asthma in young athletes poses several challenges, including the ambiguity of definitions and diagnosis of asthma resulting from exercise-induced symptoms, the best pharmacological treatments, and the nonpharmacological options for the management of disease and the challenges inherent to this age group. At a time when the regular practice of sports is increasingly being recommended for a healthy living, the support network around the young athletes is crucial to reduce the impact of asthma on their physical and emotional well-being. In this review, we examine the main issues around the definitions and clinical differentiations of asthma in young sport athletes. We discuss best practice approaches to improve the adherence to the clinical management, including nonpharmacological strategies directed at the family and trainers of athlete adolescents.

Differences in nitric oxide airway diffusion after maximum oxygen uptake test in asthmatic and nonasthmatic elite junior cross-country skiers

Asthma is common in cross-country skiers and is often treated with β₂-agonists and inhaled corticosteroids (ICS). Exhaled nitric oxide (NO) is often used to guide ICS treatment in asthma. This study investigated the change in pulmonary NO dynamics before and after a maximum oxygen uptake (V′_O2max) test.

An extended NO analysis was performed among Swedish elite junior cross-country skiers (n=25), with and without declared asthma, before and after a V′_O2max test using roller skis. Asthma was declared by six boys and two girls among whom five occasionally used ICSs.

There were no differences in baseline NO parameters between those with and without declared asthma. The median (interquartile range) diffusion capacity over airway wall (D_awNO) was 21 (17–25) mL·s⁻¹, which is much increased for this age group. After the V′_O2max test, there were statistically significant differences from the baseline fraction of exhaled NO (F_ENO50), NO flux from airways, D_awNO and alveolar NO values; but not in the NO content in airway wall (C_awNO) for all subjects together as one group. However, in the asthma group, differences were only seen in F_ENO50 and C_awNO.

Interestingly, a majority of the subjects had an increase in the D_awNO. An increase in D_awNO has been found with allergic asthma together with elevated C_awNO. The skiers did not have elevated C_awNO, which indicates an absence of inflammation in the airway wall. Modelling of lung NO production clearly shows that the asthma among our skiers is distinct from the allergic asthma in nonathletes.

NO pulmonary dynamics of junior cross-country skiers with asthma respond differently to the V′_O2maxtest than in those without asthma. Analysis of airway inflammation should be considered before inhaled corticosteroids are prescribed.https://bit.ly/3eWB1JZ

Are Respiratory Responses to Cold Air Exercise Different in Females Compared to Males? Implications for Exercise in Cold Air Environments

Research has shown that cold air exercise causes significant respiratory dysfunction, especially in female athletes. However, how female and male athletes respond to cold air exercise is not known. Thus, we aimed to compare acute respiratory responses (function, recovery and symptoms) in males and females after high-intensity cold air exercise. Eighteen (nine female) athletes completed two environmental chamber running trials at 0 °C and −20 °C (humidity 34 ± 5%) on different days in a randomized starting order. Spirometry was performed pre, 3, 6, 10, 15 and 20 min post. Respiratory symptoms were measured posttrial and heart rate and rating of perceived exertion were assessed during each trial. No significant differences in delta change (pre to post) were found at either temperature between sexes for FEV₁, FVC, FEF50% and FEF25–75%. At −20 °C, FEV₁ decreased similarly in both sexes (males: 7.5%, females: 6.3%) but not at 0 °C, p = 0.003. Postexertion respiratory function recovery and reported symptoms were not different between sexes at either temperature. These results indicate no sex-based differences in acute respiratory responses (function, recovery and symptoms) to cold air exercise. However, intense exercise at −20 °C is challenging to the respiratory system in both sexes and may lead to altered respiratory responses compared to mild winter conditions like 0 °C.