Prevalence of EIB in Young Athletes
In the general population, the EIB frequency is estimated at 5-20%, in children at 3-35%. The prevalence among adult elite athletes is higher, especially those at the Olympic-level (30-70%). These discrepancies may be due to the type of practiced sport, exposure to air pollution and allergens and maximum exercise intensity achieved, which may vary depending on the sport season17.
Prevalence of EIB among young competitors is underestimated, but a few studies report that the incidence of EIB in this group varies from 12% to 38%. Jonckheere AC reports the prevalence of EIB in 33.3% swimmers, 27.3% basketball and 12.8% football players18. Among young high school and college athletes in Mexico City, the EIB frequency was set at 7.2%, no differences between male and female sex were observed. Ventura et al. indicated a frequency of self-reported EIB symptoms in young soccer players at 5.1%19. On the contrary, Bougault et al. reported 16% of EIB in young soccer players. Among the undiagnosed young athletes suspected of EIB, the incidence was 29%20.
A high, 42.9% EIB prevalence was demonstrated in young weightlifters. Authors claim that EIB is usually associated with sports provoking elevated minute ventilation, but in this case repetitive Valsalva maneuvers may be a risk factor in EIB diagnosis.