Relationship between lung function results in the first year of life and respiratory morbidity in early childhood in patients born prematurely.

The relationship between lung function results at 6 months and 1 year of age to respiratory symptoms in the first 3 years of life in prematurely born population has been determined. In 88 infants (median gestational age, 29 weeks) thoracic gas volume (TGV) and airway resistance (R(aw)) was measured and specific conductance (SGaw) calculated at 6 months and 1 year of age. During 3 years of prospective follow-up neither TGV measured at either 6 months or 1 year, nor R(aw) and SGaw at 6 months, differed significantly between infants who were asymptomatic or symptomatic. At 1 year, however, R(aw) and SGaw were significantly higher and lower respectively in patients who were symptomatic than in those who were asymptomatic in any of the 3 years. An elevated R(aw) (> or = 50 cmH2O/L/s) measured at 1 year, but not at 6 months, was associated with a significant relative risk of symptoms in the first, second, and third year of life. We conclude that in prematurely born patients an abnormal airway resistance at 1 year predicts symptoms in early childhood.