Aim To valuate the respiratory function in VLBW (birth weight⩽1500 g) children compared with normal birth weight (NBW; birth weight ⩾2500 g) and term controls.

Methods 41 children (mean age 8.5±1.1), born between 1996 and 1999, with gestational age ⩽31 wk or with birthweight ⩽1500 gr, were compared to the same temporally nearest term-born subjects. Spirometry, pletysmography, exhaled nitric (ENO) and carbon monoxide diffusing lung capacity (DLCO) were performed before and after salbutamol inhalation.

Neonatal data were obtained from hospital records and current symptoms were ascertained from validated questionnaires.

Results VLBW show reduced expiratory flows: FEV1% (p = 0.003) and FEF 25–75% (p<0.05). The lowest was the gestational age; the lowest was FEV1% (p = 0.005) compared to VLBW without BPD and term controls.

Neonatal oxygen exposure (p = 0.047) and birthweight (p = 0.003) are also predictors of poor respiratory outcome.

VLBW with bronchopulmonary dysplasia (BPD) showed the lowest mean expiratory flows (p = 0.003) and no reaction to salbutamol inhalation.

ENO value of preterm (mean value 9.7 ppb) did not differ significantly from the control group (mean value 9.8 ppb) and neither did DLCO.

Conclusion In the surfactant area, birthweight, neonatal respiratory morbility, gestational age and oxygen supplementation appear to affect the respiratory morbidity of VLBW children. Early effects of preterm birth on the lung airways persist to school-age.