Lung function and exercise capacity in young adults born prematurely

RATIONALE: Limited information is available about the long-term outcome of lung function and exercise capacity in young adults born prematurely. OBJECTIVE: To determine long-term effects of prematurity on lung function (volumes, diffusing capacity) and exercise capacity in ex-preterms compared with healthy peers. METHODS: In a prospective cohort study, children born with a gestational age of less than 32 wk and/or a birth weight under 1,500 g were followed up for 19 yr. Participants (n=42; mean gestational age, 30 wk, and mean birth weight, 1,246 g) and healthy term control subjects (n=48) were recruited for lung function and exercise tests. MEASUREMENTS: Spirometry, bodybox (TLC(box)), diffusing capacity (Dl(CO)), bicycle ergometer test. MAIN RESULTS: Preterm birth was associated with lower FEV(1) (preterms, 95% predicted, vs. controls, 110% predicted; p<0.001), DL(CO)sb (88% predicted vs. 96% predicted, p=0.003), and exercise capacity (load, 185 vs. 216 W; p<0.001; anaerobic threshold: mean, 1,546 vs. 1,839 ml/min; p<0.001) compared with control subjects at follow-up. No differences between the groups were found in TLC(box), peak oxygen consumption (Vo(2)), and breathing reserve. No significant differences in lung function and exercise parameters were found between preterms with and without bronchopulmonary dysplasia. CONCLUSIONS: Long-term effects of prematurity were airway obstruction and a lower CO diffusing capacity compared with control subjects, although mean lung function parameters were within the normal range. Ex-preterms had a lower exercise level, which could not be explained by impaired lung function or smoking habits, but might be due to impaired physical fitness.