Jackson DJ, Gangnon RE, Evans MD, et al. Am J Respir Crit Care Med. 2008;178(7):667–672
PURPOSE OF THE STUDY. Childhood asthma is often preceded by episodes of viral wheezing. Whether specific viral infections confer more risk for future development of asthma is incompletely understood. Associations between the timing and cause of early viral infections and the subsequent risk of childhood asthma were assessed in a cohort of children at high risk.
STUDY POPULATION. A total of 259 children were monitored prospectively from birth to 6 years of age in the Childhood Origins of Asthma (COAST) study. To qualify for the COAST study, ≥1 parent was required to have respiratory allergies (defined as ≥1 positive aeroallergen skin tests) and/or a history of physician-diagnosed asthma.
METHODS. The etiology and timing of specific viral wheezing respiratory illnesses during early childhood were assessed by using nasal lavage, culture, and multiplex reverse transcriptase-polymerase chain reaction assays. The relationships of these virus-specific wheezing illnesses and other risk factors to the development of asthma were analyzed.
RESULTS. A specific viral etiology was identified in 90% of wheezing illnesses. Wheezing with respiratory syncytial virus (RSV) (odds ratio [OR]: 2.6), rhinovirus (RV) (OR: 9.8), or both RV and RSV (OR: 10) from birth to age 3 years was associated with increased asthma risk at age 6 years. In year 1, both RV wheezing (OR: 2.8) and aeroallergen sensitization (OR: 3.6) independently increased asthma risk at age 6 years. By age 3 years, wheezing with RV (OR: 25.6) was more strongly associated with asthma at age 6 years than was aeroallergen sensitization (OR: 3.4). Nearly 90% of children with wheezing with RV at age 3 subsequently developed asthma, regardless of the presence or absence of aeroallergen sensitization.
CONCLUSIONS. In children at high genetic risk, early childhood wheezing in the outpatient setting caused by RV infection is a strong risk factor for the development of asthma at age 6 years.
REVIEWER COMMENTS. We have been familiar with the previous studies focused on associations of early RSV infections and the subsequent risk for asthma. Persistent wheezing associated with early-onset RV infection seems to be a better indicator of asthma risk than RSV infection. It will be interesting to follow the COAST study results as they monitor these children throughout childhood and beyond. A still-unanswered question is: do early viral infections cause asthma or just unmask predisposed asthma?
- Copyright © 2009 by the American Academy of Pediatrics