Hollams EMa, de Klerk Na, Holt BJa, Sly PDb, Holt PGa in collaboration with the laboratory of Custovic Ac.
aThe Kids Research Institute Australia, University of Western Australia, Perth, Australia
b Queensland Children’s Medical Research Institute, Brisbane, Australia.
c Imperial College London, London, United Kingdom
In this ongoing project we are examining how well different wheezing phenotypes in the first 3 years of life predict current asthma in adolescents and young adults. From birth to age 3 years, parents of Western Australian Pregnancy (Raine Study) Cohort participants documented each instance of wheeze, including whether this occurred in the presence or absence of a cold. We performed multivariate logistic regression, adjusting for relevant potential confounders, to identify associations between wheezing phenotypes and asthma; analyses included 1216 participants at age 14y, 1034 participants at age 22y and 459 participants who were followed up at both ages. Any wheezing during the first 3 years of life was associated with around a tripling of asthma risk at age 14, and with a doubling of asthma risk at age 22. Wheezing without a cold in the 3rd year of life was the strongest predictor of asthma at 14 or 22, and was also significantly associated with increased risk of asthma that persisted from age 14 to age 22.
Measures of lung function and airway calibre were reduced in 14-year-olds who had ever wheezed by age 3 (with or without a cold) compared to those who had not. Furthermore, a higher number of episodes of wheezing with a cold by age 3 predicted poorer lung function at age 14; there was no such association for wheezing without a cold, suggesting that it is increased respiratory infections rather than wheezing alone that is likely to have a persistent detrimental effect on lung function. We are currently extending these analyses to examine lung function at age 22y. In addition, we are collaborating with Prof. Adnan Custovic (Imperial College, London), an expert in asthma and allergy epidemiology and custodian of several large British birth cohorts. His laboratory is currently conducting analyses to determine whether the UK cohorts show associations between early wheeze phenotypes and risk for asthma which are similar to those demonstrated in the Raine Study.
Plain language summary: In the first few years of life many children wheeze when they have a cold, due to their small airway size, and this often subsides with increasing age and the associated increase in lung size. However, in some children such wheezing, or wheezing in the absence of a respiratory infection, can be a precursor of asthma development. We are attempting to better understand the relationships between wheeze in early life and risk for asthma development in childhood by examining members of the Western Australian Pregnancy (Raine Study) Cohort, who have taken part in respiratory health follow-ups at age 14, age 22 or at both ages. In addition, we are collaborating with experts in the United Kingdom to determine whether the associations we see in the Raine Study, which is representative of the Western Australian population, resemble those demonstrated in British community cohorts.
Funder: National Health and Medical Research Council of Australia