Asthma, allergy and the Olympics: a 12-year survey in elite athletes

There are no comprehensive surveys relating the reported high prevalence of asthma and allergic diseases in athletes to comorbidities and immune changes associated with intense chronic exercise. This 12-year survey aims to evaluate several clinical, functional and immunological parameters in order to assess features, trend and burden of asthma, allergy, infections and autoimmune diseases, in a large homogeneous population of Olympic athletes.

Six hundred and fifty-nine Italian Olympic athletes were studied through four cross-sectional surveys performed between 2000 and 2012 before the Summer and Winter Olympics. Clinical diagnosis of allergic, autoimmune and infectious diseases was complemented by: skin-prick tests (n = 569); pulmonary function tests (n = 415); total (n = 158) and specific (n = 72) serum IgE; serum autoantibodies (n = 30), cytokines and growth factors (n = 92); flow cytometry (n = 135).

The prevalence of asthma and/or exercise-induced bronchoconstriction was 14.7%, with a significant increase (P = 0.04) from 2000 (11.3%) to 2008 (17.2%). The prevalence of rhinitis, conjunctivitis, skin allergic diseases and anaphylaxis was 26.2%, 20.0%, 14.8% and 1.1%, respectively. Sensitization to inhalant allergens was documented in 49.0% of athletes, being 32.7% in 2000 and 56.5% in 2008 (P < 0.0001). Food, drug and venom allergy was present in 7.1%, 5.0% and 2.1% of athletes, respectively. The high prevalence of asthma and allergy was associated with recurrent upper respiratory tract (10.3%) and herpes (18.2%) infections, an abnormal T cell subset profile and a general down-regulation of serum cytokines with a significantly lower IFN-γ/IL-4 ratio.

A chronic and intense physical exercise may cause a transient immunodepression with a preferential shift to a Th2 response, associated with abnormalities of the respiratory tract.