BACKGROUND AND STUDY OBJECTIVE: The point prevalence of @entity2488 ( @entity2488 ) is imperfectly associated with current @entity565 , possibly due to changes over time in bronchial responsiveness (BR). To evaluate cross-sectional and longitudinal determinants of BR, a population sample comprising 408 @entity1 and adolescents, aged 7 to 17 years at enrollment, was examined twice, 6 years apart. METHODS: Case history was obtained by interview and questionnaire. BR to inhaled @entity112 , pulmonary function, and skin prick test reactivity were measured using standard techniques. RESULTS: The point prevalence of @entity2488 (the concentration of @entity112 causing a 20% decline in FEV1 <8 mg/mL) declined from childhood to early adulthood (25% and 6%, respectively; p<0.001); and similarly a decline in @entity112 dose-response slope was observed. At both surveys, prechallenge FEV1 percent predicted, @entity565 , and @entity402 , especially @entity402 to @entity6711 ( @entity6711 ), were important determinants for the degree of BR. After adjustment for prechallenge FEV1 percent predicted, no male-female difference was observed in degree of BR. Lower FEV1 percent predicted (p=0.003), @entity565 (p<0.001), higher degree of BR (p=0.003), and @entity402 to @entity6711 (p=0.007) at enrollment predicted a higher degree of BR at the second survey (degree of BR at second survey adjusted for prechallenge FEV1). Furthermore, new @entity565 (p<0.001) and/or @entity402 to @entity6711 (p=0.003) were associated with higher BR at the second survey. Confining the analysis to nonasthmatics showed that subjects with new or persistent @entity402 to @entity6711 had significantly increased BR compared with nonatopic subjects; and, moreover, prechallenge FEV1 percent predicted was significantly correlated with BR. CONCLUSIONS: BR declines from childhood to early adulthood, possibly reflecting the increase in airway caliber. The level of FEV1 and @entity402 , especially to @entity6711 , are important determinants for changes over time in level of BR, also in nonasthmatic subjects.

Longitudinal determinants of bronchial responsiveness to inhaled XXXX .

@entity1 :: ('9606', 'Species') :: ['children'] @entity2488 :: ('MESH:D001982', 'Disease') :: ['BHR', 'bronchial hyperresponsiveness'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity402 :: ('MESH:C564133', 'Disease') :: ['atopy'] @entity112 :: ('MESH:D006632', 'Chemical') :: ['histamine'] @entity6711 :: ('MESH:D008924', 'Disease') :: ['HDM', 'house dust mite']
@entity112 :: (MESH:D006632,Chemical) :: ['histamine']
