title: Body composition and plasma levels of inflammatory biomarkers in COPD.
abstract: Previous studies suggest a relationship between systemic inflammation and body composition in chronic obstructive pulmonary disease (COPD). We examined the relationships between body composition (fat free mass index (FFMI) kg·m(-2) and fat mass index (FMI) kg·m(-2)) and three plasma inflammatory markers C-reactive Protein (CRP), soluble tumour necrosis factor receptor 1 (sTNF-R1) and osteoprotegerin (OPG) in 409 stable COPD patients (aged 40-75 yrs, Global Initiative for Obstructive Chronic Lung Disease (GOLD) categories II-IV, 249 male) from the Bergen COPD Cohort Study in Norway. FFMI and FMI were measured by bioelectrical impedance. Plasma CRP (μg·mL(-1)), sTNF-R1 (pg·mL(-1)) and OPG (ng·mL(-1)) were determined by enzyme immunoassays. Correlations and Kruskal-Wallis tests were used for bivariate analyses. Linear regression models were fitted for each of the three markers, CRP, sTNF-R1 and OPG, with FFMI and FMI as explanatory variables including sex, age, smoking habits, GOLD category, hypoxaemia, Charlson Comorbidity Index and inhaled steroid use as potential confounders. CRP and sTNF-R1 levels correlated positively with both FFMI and FMI. The adjusted regression coefficients for an increase in logCRP per unit increase in FFMI was 1.23 (1.14-1.33) kg·m(-2) and 24.9 (11.8-38.1) kg·m(-2) for sTNF-R1. Higher FMI was associated with a lower OPG, with adjusted regression coefficient -0.14 (-0.23- -0.04), whereas FFMI was unrelated to OPG. In conclusion, COPD patients with low FFMI had lower not higher plasma levels of CRP and sTNF-R1, whereas higher fat mass was associated with higher CRP and sTNF-R1 and lower OPG.
authors.affiliation: Dept of Thoracic Medicine, Haukeland University Hospital, Jonas Lies vei, 5021 Bergen, Norway. tomas.eagan@med.uib.no
authors.forename: T M L
authors.initials: TM
authors.lastname: Eagan
authors.forename: P
authors.initials: P
authors.lastname: Aukrust
authors.forename: T
authors.initials: T
authors.lastname: Ueland
authors.forename: J A
authors.initials: JA
authors.lastname: Hardie
authors.forename: A
authors.initials: A
authors.lastname: Johannessen
authors.forename: T E
authors.initials: TE
authors.lastname: Mollnes
authors.forename: J K
authors.initials: JK
authors.lastname: Damås
authors.forename: P S
authors.initials: PS
authors.lastname: Bakke
authors.forename: P D
authors.initials: PD
authors.lastname: Wagner
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D001823:Body Composition / Q000502:physiology*; D002097:C-Reactive Protein / Q000378:metabolism; D002100:Cachexia / Q000276:immunology* / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053244:Osteoprotegerin / Q000097:blood; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology* / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000097:blood
chemical_list: D015415:Biomarkers; D053244:Osteoprotegerin; D047888:Receptors, Tumor Necrosis Factor, Type I; D002097:C-Reactive Protein