In a group of Swedish elite endurance athletes, the incidence rate of self-reported, physician-diagnosed asthma was reported to be high. A prospective postal questionnaire study, designed to explore this issue, was conducted in this population, and the results were published in the Journal of Asthma.1
Investigators sought to estimate the incidence rate of physician-diagnosed asthma in a select group of elite endurance athletes, including skiers and orienteers. In addition, the researchers aimed to evaluate the risk factors for incident physician-diagnosed asthma in this population. A prospective annual Swedish postal report, which was conducted between 2011 and 2016, served as the basis of the current study.2
A total of 666 participants were involved in the study, which included athletes from Swedish National teams, pupils at Swedish National elite upper secondary sport schools, students at 1 of 3 universities with elite sport contracts, and those with National top 80 ranking in orienteering in 2012. All the participants were currently competing in cross-country skiing, ski-orienteering, or biathlon.
The population at risk (PAR) was defined as “participants without physician-diagnosed asthma at baseline (at inclusion of the study = year 1).”1 The researchers explained that the incidence rate of physician-diagnosed asthma in the PAR was computed by dividing the number of athletes who fulfilled the study criteria for physician-diagnosed asthma during follow-up (ie, the number of incident cases of asthma) by the summarized time at risk in person-years. The athletes who were in the PAR contributed 1 person-year for every year of follow-up without having been diagnosed with asthma. Any athlete who was diagnosed with asthma contributed 0.5 person-years that year. The incidence rate was conveyed per 1000 person-years. The incident rate of physician-diagnosed asthma was computed in individuals who did not have asthma at baseline (n=449). A multivariate logistic regression analysis was used to identify risk factors for incident physician-diagnosed asthma.
At baseline, 591 of the total population of 666 individuals had responded, which translated to a response rate of 88.7%. At study onset, the median participant age was 17 years (range, 15-36 years). In the study population, 68.8% (407 of 591) of the participants were skiers and 31.1% (184 of 591) of the participants were orienteers.
At baseline, the prevalence of asthma was 23.9% (141 of 591) of participants. Results demonstrated that the incidence rate of physician-diagnosed asthma was 61.2 (95% CI, 45.7-80.3) per 1000 person-years. The risk factors for incident physician-diagnosed asthma were family history of asthma (odds ratio [OR], 1.97; 95% CI, 1.04-3.68), being a skier (OR, 3.01; 95% CI, 1.42-7.21), and wheezing without having a cold (OR, 4.15; 95% CI, 1.81-9.26).
The investigators concluded that based on the findings from this study, the high prevalence and incidence of asthma in athletes require the implementation of thorough diagnostic procedures within individual healthcare systems. A need exists to assess primary preventive measures, particularly in skiers. Additional studies are warranted to evaluate the extent to which a remission of asthma in elite endurance athletes is reported when such measures have been enacted.
1. Irewall T, Söderström L, Lindberg A, Stenfors N. High incidence rate of asthma among elite endurance athletes: a prospective 4-year survey [published online February 20, 2020]. J Asthma. doi:10.1080/02770903.2020.1728769
2. Norqvist J, Eriksson L, Söderström L, Lindberg A, Stenfors N. Self-reported physician-diagnosed asthma among Swedish adolescent, adult and former elite endurance athletes. J Asthma. 2015;52(10):1046-1053.