Prevalence of asthma elevated in competitive cross-country skiers

The prevalence of non-allergic asthma was elevated among successful competitive cross-country skiers compared with the general population due to their intensive training schedule, researchers reported in BMJ Open Sport & Exercise Medicine.

“The prevalence of asthma has not been thoroughly assessed by performance level in cross-country skiers, but one might speculate that asthma is most common among those who train the most,” Rikhard Mäki-Heikkilä, MD, doctoral researcher at Tampere University, Finland, and colleagues wrote. “Indeed, in the Winter Olympics from 2002 through 2010, athletes using inhaled [beta-2] agonists won approximately twice as many medals as their proportion of all the athletes across all disciplines. However, their asthma status was not explicitly reported.”

Researchers sent a postal questionnaire to 1,282 Finnish cross-country skiers who were enrolled in the largest 2019 winter national competitions in Finland and a random sample of 1,754 individuals in the general population of the same age. The response rate was 27.4% for cross-country skiers (median age, 16.5 years; 58.1% women) and 19.5% for those in the general population (median age, 17 years; 69.5% women).

Using the International Ski Federation ranking points, researchers measured the success level of the cross-country skiers. Asthma was defined as self-reported or physician-diagnosed disease and considered allergic if it was associated with a physician-diagnosed allergy and if exposure to allergens triggered asthma exacerbations.

The prevalence of asthma was higher among cross-country skiers compared with the general population (25.9% vs. 9.2%; P < .001). Asthma prevalence was highest among the 56.1% of cross-country skiers who were in the most successful quartile.

The prevalence of nonallergic asthma was also higher among cross-country skiers compared with the general population (60.1% vs. 38.7%; P = .036). Cross-country skiers had a higher risk for nonallergic asthma (OR = 5.05; 95% CI, 2.65-9.61) compared with allergic asthma (OR = 1.92; 95% CI, 1.08-3.42).

Higher training volume among cross-country skiers was also associated with nonallergic asthma, while age, family asthma history and allergic rhinitis were associated with allergic asthma.

“Prospective studies with direct measures of the type and level of airway inflammation would verify a causal relationship between training volume and the type, severity and prognosis of asthma in competitive cross-country skiers,” the researchers wrote.

Reference:

• Intensive training linked to heightened asthma risk in cross-country skiers. Published June 13, 2022. Accessed June 21, 2022.