Neonates with reduced neonatal lung function have systemic low-grade inflammation

Background Children and adults with asthma and impaired lung function have been reported to have low-grade systemic inflammation, but it is unknown whether this inflammation starts before symptoms and in particular whether low-grade inflammation is present in asymptomatic neonates with reduced lung function. Objective We sought to investigate the possible association between neonatal lung function and biomarkers of systemic inflammation. Methods Plasma levels of high-sensitivity C-reactive protein (hs-CRP), IL-1β, IL-6, TNF-α, and CXCL8 (IL-8) were measured at age 6 months in 300 children of the Copenhagen Prospective Study on Asthma in Childhood₂₀₀₀ birth cohort who had completed neonatal lung function testing at age 4 weeks. Associations between neonatal lung function indices and inflammatory biomarkers were investigated by conventional statistics and unsupervised principal component analysis. Results The neonatal forced expiratory volume at 0.5 seconds was inversely associated with hs-CRP (β-coefficient, -0.12; 95% CI, -0.21 to -0.04; P <.01) and IL-6 (β-coefficient, -0.10; 95% CI, -0.18 to -0.01; P =.03) levels. The multivariate principal component analysis approach, including hs-CRP, IL-6, TNF-α, and CXCL8, confirmed a uniform upregulated inflammatory profile in children with reduced forced expiratory volume at 0.5 seconds (P =.02). Adjusting for body mass index at birth, maternal smoking, older children in the home, neonatal bacterial airway colonization, infections 14 days before, and asthmatic symptoms, as well as virus-induced wheezing, at any time before biomarker assessment at age 6 months did not affect the associations. Conclusion Diminished neonatal lung function is associated with upregulated systemic inflammatory markers, such as hs-CRP.