Introduction: Chronic respiratory symptoms in survivors of preterm birth may be underpinned by active pulmonary inflammation, however limited evidence exists to support this theory. Our study aimed to assess if inflammatory biomarkers were correlated to lung function in those born very preterm (<32 weeks GA).

Methods: Exhaled breath condensate (EBC), urine samples and spirometry data were collected from children and young adults during a scheduled research visit. Concentrations of biomarkers for inflammation (interleukin-8, leukotriene B4, cysteinyl leukotriene), epithelial injury (clara cell protein) and oxidative stress (8-isoprostane) were measured via ELISA. Concentrations were normalised to specific gravity and Spearman?s correlation used to assess relationship with lung function (FEV1, FVC and the FEV1/FVC ratio).

Results: Samples were analysed from participants born very preterm (n=197; 13.7 ± 4.8 years) and at term (n=61; 14.3 ± 5.5 years).  Biomarker concentrations were below detection limits in EBC samples. Urinary concentrations of 8-isoprostane were significantly elevated in those born preterm (562 [59 ? 2252] vs 771 [60-2340] pg/ml; p=0.02) but did not differ between those with (n=83) or without (n=114) a BPD diagnosis and showed no correlation to spirometry outcomes. All remaining urinary biomarkers showed no statistical difference between cohorts and no correlation to pulmonary function (p>0.05).

Conclusion: Spirometry data was not correlated to systemic inflammation; however pulmonary inflammation was unable to be directly assessed. Systemic findings of elevated 8-isoprostane highlight the ongoing role of oxidative stress in those born preterm.