The study was renewed in 2001 to follow the birth cohort into early adulthood in order to generate data on the mechanisms and risk factors associated with asthma in early adult life. Specifically the study will: 1) identify factors that alter persistence and remission of asthma symptoms among young adults who developed asthma in childhood; 2) assess the role of persistent eosinophilia during childhood as a mechanism which determines progression and incidence of asthma in early adult life, and prevalence of persistent bronchial hyperresponsiveness (BHR); 3) measure noninvasive markers of airway inflammation in early adult life, and identify correlates of these markers, both with childhood and current asthma symptoms, BHR and immune system indicators of allergy; 4) predict early (by age 20 ) decline in lung function with reference to childhood lower respiratory tract illnesses, asthma-like symptoms, and the initiation of smoking; and 5) investigate the role of gender in incidence of and risk factors for asthma during adolescence and young adult life.