Pulmonary outcome in adolescents of extreme preterm birth: a regional cohort study

Aims: The pulmonary outcome of extreme prematurity remains to be established in adults. We determined respiratory health and lung function status in a population-based, complete cohort of young preterms approaching adulthood. Methods. Forty-six preterms with gestational age less than or equal to28 wk or birthweight less than or equal to1000 g, born between 1982 and 1985, were compared to the temporally nearest term-born subject of equal gender. Spirometry, plethysmography, reversibility test to salbutamol and methacholine bronchial provocation test were performed. Neonatal data were obtained from hospital records and current symptoms from validated questionnaires. Results: When entering the study at a mean age of 17.7 (SD: 1.2) y, a doctor's diagnosis of asthma and use of asthma inhalers were significantly more prevalent among preterms than controls (one asthmatic control compared to nine preterms, all but one using asthma inhalers). Peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV1) were decreased and the discrepancies relative to controls increased parallel to increased severity of neonatal lung disease. Parameters of increased neonatal oxygen exposure significantly predicted FEV1. Adjusted for height, gender and age, FEV1 was reduced by a mean of 580 ml/s in subjects with a history of bronchopulmonary dysplasia. Fifty-six percent of preterms had a positive methacholine provocation test compared to 26% of controls. Conclusion: A substantially decreased FEV1, increased bronchial hyperresponsiveness and a number of established risk factors for steeper age-related decline in lung function were observed in preterms. A potential for early onset chronic obstructive pulmonary disease is present in subsets of this group.