GROWTH OF AIRWAYS AND AIR SPACES IN TEENAGERS IS RELATED TO SEX BUT NOT TO SYMPTOMS

To determine growth patterns of the lung and airways in adolescents, w e analyzed maximal expiratory flow-volume curves, closing capacity, an d residual volume. They were obtained every 6 mo for up to 7 yr in 430 boys and 125 girls (11-19 yr), of whom 143 boys and 36 girls were cla ssified as symptomatic; symptoms were most often minor and limited to childhood. Development of flows vs. volumes was used to investigate gr owth of the airways relative to lung size. A model of isotropic growth of the airways and air spaces (J. Appl. Physiol. 65: 822-828, 1988) w as modified for increasing elastic recoil pressure with growth. Growth of airways relative to volume occurred faster in teenage boys than in teenage girls and was compatible with isotropic growth in 92% of asym ptomatic boys and in 44% of asymptomatic girls: dysanaptic growth in t eenage girls seems to be a normal phenomenon and not a unique characte ristic of symptomatic subjects. Subjects with respiratory symptoms in childhood and/or adolescence have lower flows for a given lung size an d airway closure at a greater lung volume when they enter adulthood. H owever, no difference in patterns of lung growth was observed in assoc iation with the presence of respiratory symptoms.