Background:
Low-grade systemic inflammation is associated with impaired lung function. Few studies have examined if C-reactive protein (CRP), blood eosinophil (B-Eos), and blood neutrophil (B-Neu) counts offer additive information in relation to lung function. The aim of this study was to analyse associations between CRP, BEos, and B-Neu and effects on lung function, with special regards to additive information.
Methods:
Cross-sectional study on 7,753 participants, 20-80 years of age, in the National Health and Nutrition Examination Survey. Gender-based tertiles for CRP, B-Eos, and B-Neu were analyzed in relation to forced expiratory volume in 1 second (FEV1 % predicted), forced vital capacity (FVC % predicted), and FEV1/FVC ratio.
Results:
CRP, B-Eos, and B-Neu were inversely related to FEV1 and FVC. Only B-Eos and B-Neu were inversely related to FEV1/FVC ratio. Further, lower lung function was found with increased number of elevated
inflammatory markers in the highest tertile (one, two or three vs. non elevated) for FEV1 (% predicted): β-coefficients (95% CI) -2.20(-2.98, -1.41), -4.43 (-5.39, -3.45), and -6.43(-8.07, -4.79), all P=0.001; FVC (% predicted): -1.70 (-2.42, -0.98), -3.17 (-4.06, -2.29), and -5.34 (-6.85, -3.84), all P=0.001.
Conclusion:
CRP, B-Eos, and B-Neu offer independent and additive information in relation to lower FEV1 and FVC in the general population. This indicates that a combination of biomarkers yields more information than the biomarkers assessed individually. The mechanisms appear to be different, as B-Neu and B-Eos seem to relate more closely to obstructive impairment, e.g., lower FEV1/FVC ratio, which was not found for CRP.
2018.