Wheezing in 18-year-olds is associated with active smoking, but only if the individual had reduced lung function in infancy, according to a report published online ahead of print in JAMA Pediatrics.

Authors noted, however, that the relationship between wheeze and age at onset of airway dysfunction is yet to be clarified.

A wheeze persisting from ages 6 to 18 years is associated with multiple factors, including reduced infant lung function, infant-onset atopy, maternal asthma, and active smoking, researchers found.

“These results suggest that reduced early airway function and later exposures such as smoking are important to the cause of obstructive respiratory diseases in young adults,” the authors wrote. “Interventions aimed at preventing young children with asthma symptoms and reduced lung function from smoking might prevent persisting symptoms of obstructive airways disease.”

For the study, investigators examined data on 150 participants in a birth cohort who had been followed from one month to 18 years old. Of those, 37 participants (255%) had recent wheeze and 20 (13%) were diagnosed with asthma, according to the results.

Compared with the no-wheeze group, persistent wheeze was independently associated with reduced percentage of predicted V’maxFRC was also associated with atopy in infancy, maternal asthma, and active smoking, according to researchers.