PURPOSE OF THE STUDY.
To define the relationships among specific viral illnesses and the type and timing of aeroallergen sensitization with the persistence of asthma into adolescence.
This is a prospective cohort study that enrolled 289 newborns who had a parental history of respiratory allergies and/or asthma and were followed to age 13 years (n = 213).
After enrollment, the infants had scheduled visits at ages 2, 4, 6, 9, and 12 months and annually thereafter. They were also seen during periods of acute illness. At these visits, nasal lavage was collected and analyzed for respiratory viruses. The viral panel included RSV, RV, influenza types A and B, parainfluenza virus types 1 to 4, adenovirus, coronavirus, and enterovirus. Allergen-specific IgE levels were determined at ages 1, 2, and 3 years for Dermatophagoides pteronyssinus, Dermatophagoides farina, Alternaria alternata, and dog and cat allergens and were repeated at ages 5, 6, 9, 11, and 13 years with the addition of ragweed, silver birch, timothy grass, and cockroach. Wheezing during the first 3 years of life and asthma during school age were determined by physician diagnosis, the use of β agonists, daily asthma controller medications, or the use of oral steroids for exacerbation.
A total of 454 wheezing illnesses were documented during the first 3 years of life. Viruses detected included the following: RV (48%), RSV (21%), parainfluenza viruses (12%), metapneumovirus (7%), coronaviruses (5%), adenovirus (4%), influenza types A and B (4%), and enteroviruses (2%). RSV-induced wheezing accounted for an increased risk of asthma during school ages 6, 8, and 11 years; however, the association was lost by age 13 years. On the other hand, RV-associated wheezing during early childhood was associated with asthma that persisted to age 13 years (OR +3.3; 95% CI, 1.5–7.1). Additionally, 65% of children who were sensitized by age 1 year had asthma that persisted to age 13 years; children who were not sensitized by 1 year of age but were sensitized by age 5 years had a 40% rate of asthma in adolescence, and the remaining children who were not sensitized by age 5 years had an asthma rate of 17%. Subsequently, those with both early-life, RV-associated wheezing and aeroallergen sensitization by age 3 years had the highest risk of persistent asthma. Protective factors that reduced asthma risk at age 13 years included the presence of a cat in the home at the time of birth, while the protective impact of a dog in the home waned by age 13 years.
This study found that high-risk children with a parental history of allergies and/or asthma were more likely to develop asthma that persisted into adolescence when they had RV and aeroallergen sensitization in early childhood.
This study highlights that the timing of wheezing illness, the type of viral infection causing the illness, and aeroallergen sensitization are all important influences on the development of persistent asthma. This study demonstrated that RV-associated wheezing correlates with longer-lasting asthma than RSV-associated wheezing in early childhood and suggests that prevention strategies are needed to impact long-term outcomes.
- Copyright © 2017 by the American Academy of Pediatrics