Viral and Non-viral Episodes of Wheezing in Early Life and the
Development of Asthma and Respiratory Phenotypes Among Urban Children
Abstract
Background: Viral wheeze is an important risk factor for
asthma, which comprises several respiratory phenotypes. We sought to
understand if the etiology of early life wheezing illnesses relates to
childhood respiratory and asthma phenotypes. Methods: Data were
collected prospectively on 429 children in the Urban Environment and
Childhood Asthma (URECA) birth cohort study through age 10 years. We
identified wheezing illnesses and the corresponding viral etiology (PCR
testing of nasal mucus) during the first three years of life. Six
phenotypes of respiratory health were identified at 10 years of age
based on trajectories of wheezing, allergic sensitization, and lung
function. We compared etiology of early wheezing illnesses on these
respiratory phenotypes and the development of asthma. Results:
In the first three years of life, at least one virus was detected in 324
(67%) of the 483 wheezing episodes documented in the study cohort.
Using hierarchical partitioning we found that non-viral wheezing
episodes accounted for the greatest variance on asthma diagnosed at both
7 and 10 years of age (8.0% and 5.8% respectively). Rhinovirus
wheezing illnesses explained the most variance on respiratory phenotype
outcome followed by non-viral wheezing episodes (4.9% and 3.9%
respectively) at 10 years of age. Conclusion and Relevance:
Within this high-risk urban-residing cohort early life, non-viral
wheezing episodes were frequently identified and associated with asthma
development. Though rhinovirus wheezing illnesses had the greatest
association with phenotype outcome, the specific etiology of wheezing
episode in early life provided limited information about subsequent
wheezing phenotypes.