Lung function in adult survivors of very low birth weight, with and without bronchopulmonary dysplasia

Introduction: The lung function outcome of cohorts of very low birth weight (VLBW; birth weight <1501 g) survivors born in the late 1970s or early 1980s into adulthood at an age when lung growth would be expected to have ceased is not well described. The aim of this study was to report lung function data in adulthood of VLBW survivors compared with normal birth weight controls (>2499 g), and in those who had bronchopulmonary dysplasia (BPD) compared with those without BPD.

Materials and methods: Spirometry and lung volumes were measured according to standard guidelines when subjects were in their mid-20s; there were 47 survivors of birth weight <1000 g, 40 of birth weight 1000-1500 g, and 20 controls of birth weight >2499 g. Results were converted to z-scores.

Results: Both subgroups with birth weight <1501 g had significant reductions in airflow compared with controls, but not compared with each other. There were no significant differences between groups in variables reflecting air trapping. Within the VLBW cohort, those with BPD (n = 24) had reductions in airflow, including the z-score for the forced expired volume in 1 sec (FEV1 ), compared with those without BPD (n = 63). Within the VLBW cohort, there were positive relationships between FEV1 measurements earlier in childhood with those obtained at 25 years of age; these relationships were stronger in those who had BPD in the newborn period, and increased over time.

Conclusions: VLBW survivors continue to have airways obstruction in their mid-20s compared with controls, particularly those who had BPD in the newborn period.