AsthmaIncidenceAnti-Asthmatic AgentsAsthma, Exercise-InducedAdministration, InhalationPeak Expiratory Flow RateAsthma, OccupationalForced Expiratory VolumeRisk FactorsRespiratory SoundsBronchodilator AgentsBronchial HyperreactivityAllergensAdrenal Cortex HormonesHypersensitivityPrevalenceHypersensitivity, ImmediateRespiratory Function TestsRhinitis