Adults with a history of childhood asthma frequently have irreversible deficits in lung function, a study shows. Longer duration of childhood asthma and premature birth increase the likelihood of lung trouble later in life, the researchers found.

Asthma, usually defined as reversible airway obstruction, early in life may affect lung function later - but whether or not these effects are reversible is not clear, Dr. N. Franklin Adkinson of the Johns Hopkins School of Medicine in Baltimore and colleagues point out in their report in the Journal of Allergy and Clinical Immunology.

To investigate, they tested lung function in 84 adults aged 17 to 30 who had asthma during childhood. Forty of these individuals had abnormal lung function based on the results of standard tests.

Being born prematurely - at 34 weeks gestation or earlier - increased the risk of abnormal lung function more than 10-fold. Lung function in childhood was significantly correlated with adult lung function for all study participants.

Adults with abnormal lung function also had a longer duration of asthma as children compared with those with normal lung function in adulthood.

“Our results suggest that childhood allergic asthma is associated with airway obstruction that is not easily reversed with bronchodilators or steroids in a substantial subset of asthmatic patients, and this subset might be identified earlier in life,” they conclude.

“Further study is necessary to explore the genetic factors and early exposures that initiate these airway changes and to facilitate better treatment and prevention.”

SOURCE: Journal of Allergy and Clinical Immunology, Decembe 2005.