Monday, June 11, 2018

Clinical phenotypes of bronchial hyperresponsiveness in school-aged children.


Abstract


BACKGROUND:

Bronchial hyperresponsiveness (BHR), one of the key features of asthma, shows a diverse natural course in school-aged children, but, studies on BHR phenotypes are lacking.

OBJECTIVE:

We classified BHR phenotypes according to onset age and persistence in children and investigated the characteristics and factors associated with each phenotype in a longitudinal study.

METHODS:

We analyzed 1,305 elementary school children from the Children's HEalth and Environmental Research (CHEER) study, a 4-year prospective follow-up study with 2-year intervals starting at a mean age of 7 years. Total serum IgE levels and blood eosinophils (%) were measured, and allergy work-up including methacholine challenge tests with ISSAC questionnaire were performed at each survey.

RESULTS:

We classified the four BHR phenotypes as non-BHR (n=942, 72.2%), early-onset transient BHR (n=201, 15.4%), late-onset BHR (n=87, 6.7%), and early-onset persistent BHR (n=75, 5.7%). Early-onset persistent BHR is characterized by an increased eosinophils (%), total serum IgE level, sensitization rate, a decreased lung function and an increased risk of newly diagnosed asthma during follow-up (aOR, 3.89; 95% CI, 1.70-8.88). The two early-onset phenotypes were associated with peripheral airway dysfunction. The late-onset BHR phenotype related with increased risks of AR symptoms at baseline and later sensitization against inhalant allergens.

CONCLUSION:

The early-onset persistent BHR phenotype in school-aged children is associated with high atopic burden and increased risk of newly diagnosed asthma, whereas the late-onset BHR phenotype related with later sensitization and AR symptoms. Diverse BHR phenotypes in children have specific characteristics that require targeted follow-ups.

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