Wheezing patterns in early childhood can predict pulmonary function and the development of asthma in adolescence in a high-risk population, a study finds.
The study validates four clinically distinct early-life wheezing phenotypes identified by the landmark Tucson Children’s Respiratory Study in a high-risk population:
• Never.
• Transient early – wheezing before age 3 years but not at age 6 years.
• Late onset – wheezing at age 6 years but not before age 3 years.
• Persistent – wheezing before age 3 years and at age 6 years.
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Previously, these phenotypes were shown to be associated with respiratory outcomes in adolescence but not with diagnosed asthma or in genetically predisposed children. The present study extends the associations with these early phenotypes to a high-risk adolescent population, said Meghan B. Azad, Ph.D., of the University of Manitoba, Winnipeg, and her associates.
The study findings were based on findings in 459 children previously enrolled in the Canadian Asthma Primary Prevention Study cohort; this was a prenatally randomized prevention trial in children at high genetic risk for asthma. The distribution of early-wheeze phenotypes was 51% never, 28% transient early, 9% late onset, and 13% persistent (JAMA Pediatrics. 2016 Feb 8. doi: 10.1001/jamapediatrics.2015.4127).
Across all four phenotypes, the authors found a strong gradient of decreasing lung function and increasing asthma risk by age 15 years. Asthma, assessed at 15 years in 320 adolescents, was associated with early-wheeze phenotypes: the prevalence of asthma was 5% among never, 19% among transient early, 27% among late onset, and 42% among persistent phenotypes.
At age 15, early-wheezing phenotypes were not associated with atopic dermatitis or allergic rhinitis. Atopy before 2 years of age was associated with persistent wheeze, which was in turn associated with a 12-fold increased risk of diagnosed asthma by age 15.
“Our results are consistent with other cohorts” and the study “extends these findings through adolescence in a high-risk cohort and demonstrates that asthma-associated deficits are already present at a young age. Collectively, these data show that early wheezing patterns provide clinically meaningful information and suggest that strategies to reduce early-life wheezing and atopic sensitization could have long-term health benefits,” Dr. Azad and her colleagues concluded.
Proven strategies to prevent wheezing include avoiding dust, pets, and tobacco smoke; encouragement of breastfeeding; and delayed introduction of solid foods.
The research was supported by the Canadian Institutes of Health Research. The investigators reported no relevant financial disclosures.