title: Association between combined interleukin-6 and C-reactive protein levels and pulmonary function in older women: results from the Women's Health and Aging Studies I and II.
abstract: OBJECTIVE
  To determine whether combined higher interleukin-6 (IL-6) and C-reactive protein (CRP) levels are associated with lower pulmonary function levels in older women, accounting for chronic inflammatory diseases, physical function, and other factors associated with inflammation.
  
  
  METHODS
  Cross-sectional study using data from two prospective cohorts.
  
  
  METHODS
  Baltimore, Maryland.
  
  
  METHODS
  Eight hundred forty disabled and 332 higher-functioning community-dwelling women aged 65 and older from the Women's Health and Aging Studies (WHAS) I and II, respectively.
  
  
  METHODS
  IL-6 and CRP, combined according to their tertile concentrations, and pulmonary function measures, assessed according to forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC).
  
  
  RESULTS
  In WHAS I and II, similar dose-response trends were observed between combined higher IL-6 and CRP levels and lower pulmonary function levels. In WHAS I (disabled women), the combined highest IL-6 and CRP levels were associated with the lowest levels of FEV₁ (mean 137.0 mL, 95% confidence interval (CI)=128.4-145.7 mL) and FVC (mean 191.7 mL, 95% CI=180.4-202.9 mL). Similarly, in WHAS II (higher-functioning women), the combined highest IL-6 and CRP levels were associated with the lowest levels of FEV₁ (mean 1,543 mL, [corrected] 95% CI=146.3-170.4 mL) and FVC (mean 224.2 mL, 95% CI=209.9-238.5 mL).
  
  
  CONCLUSIONS
  Combined elevations in IL-6 and CRP were associated with the lowest pulmonary function levels in older women. These findings suggest that high IL-6 and CRP levels may be an indication of prevalent impaired pulmonary function. Future studies should determine whether measurement of IL-6 and CRP could enhance current methods of monitoring respiratory diseases beyond that provided by pulmonary function measures.
authors.affiliation: Section of Geriatrics, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. sandy.chang@yale.edu
authors.forename: Sandy S
authors.initials: SS
authors.lastname: Chang
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Vaz Fragoso
authors.forename: Peter H
authors.initials: PH
authors.lastname: Van Ness
authors.forename: Linda P
authors.initials: LP
authors.lastname: Fried
authors.forename: Mary E
authors.initials: ME
authors.lastname: Tinetti
mesh_terms: D000368:Aged; D015142:Baltimore / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D002908:Chronic Disease / Q000453:epidemiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000453:epidemiology; D015850:Interleukin-6 / Q000097:blood*; D016014:Linear Models; D008171:Lung Diseases / Q000097:blood / Q000453:epidemiology*; D015999:Multivariate Analysis; D012129:Respiratory Function Tests; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D002097:C-Reactive Protein