title: Preinfection systemic inflammatory markers and risk of hospitalization due to pneumonia.
abstract: BACKGROUND
  Elevated proinflammatory cytokines are associated with severity of pneumonia, but the role of preinfection cytokine levels in the predisposition to pneumonia in humans is less clear.
  
  
  OBJECTIVE
  To ascertain role of preinfection inflammatory markers on susceptibility to community-acquired pneumonia (CAP).
  
  
  METHODS
  Longitudinal analysis over 6.5 yr of a cohort that consisted of 70- to 79-yr-old well-functioning elderly individuals.
  
  
  METHODS
  Association between preinfection tumor necrosis factor (TNF), interleukin 6 (IL-6), and C-reactive protein (CRP) levels and CAP requiring hospitalization.
  
  
  RESULTS
  Of the 3,075 participants, 161 (5.2%) developed at least one episode of CAP requiring hospitalization over a median duration of 3.3 yr. The highest tertiles of TNF (> 3.7 pg/ml) and IL-6 (> 2.4 pg/ml) were associated with increased risk of CAP, and the adjusted odds ratios were 1.6 (95% confidence interval [CI], 1.02-2.7) and 1.7 (95% CI, 1.1-2.8), respectively. The adjusted risk of CAP with at least one of these markers in the highest tertile was 1.6 (95% CI, 1.1-2.3). TNF and IL-6 levels in the highest tertile had a synergistic effect (p = 0.01 for interaction), and risk of CAP for both markers in the highest tertile was 2.8 (95% CI, 1.8-4.3). An FEV(1) of 50% or less of predicted was associated with the highest risk of CAP (adjusted odds ratio, 3.6; 95% CI, 2.3-5.6). Furthermore, TNF and IL-6 levels modified risk of CAP in participants with coexisting medical conditions and history of smoking.
  
  
  CONCLUSIONS
  In the well-functioning elderly subjects, preinfection systemic levels of TNF and IL-6 were associated with higher risk of CAP requiring hospitalization in smokers and those with coexisting medical conditions.
authors.affiliation: Department of Critical Care Medicine, 3550 Terrace Street, Pittsburgh PA 15261, USA. yendes@upmc.edu
authors.forename: Sachin
authors.initials: S
authors.lastname: Yende
authors.forename: Elaine I
authors.initials: EI
authors.lastname: Tuomanen
authors.forename: Richard
authors.initials: R
authors.lastname: Wunderink
authors.forename: Alka
authors.initials: A
authors.lastname: Kanaya
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Tamara
authors.initials: T
authors.lastname: Harris
authors.forename: Nathalie
authors.initials: N
authors.lastname: de Rekeneire
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D016017:Odds Ratio; D011014:Pneumonia / Q000097:blood* / Q000473:pathology; D011446:Prospective Studies; D012307:Risk Factors; D048069:Tumor Necrosis Factors / Q000097:blood*
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D048069:Tumor Necrosis Factors; D002097:C-Reactive Protein