title: The associations of interleukin-6 (IL-6) and downstream inflammatory markers with risk of cardiovascular disease: the Caerphilly Study.
abstract: OBJECTIVE
  Interleukin-6 (IL-6) is a key pro-inflammatory cytokine which mediates expression of several 'downstream' inflammatory markers and may play a role in atherothrombosis. However, it is not yet known whether IL-6 plays a role in mediating the associations of each marker with risk of coronary heart disease (CHD) or ischaemic stroke (IS).
  
  
  RESULTS
  We examined the role of IL-6 and several "downstream" markers of inflammation (leucocyte counts, plasma and serum viscosity, fibrinogen, C-reactive protein, alpha1-antitrypsin and alpha2-macroglobulin) with risk of subsequent CHD, IS, and a combined endpoint (CHD/IS) in a population of British men. 2208 men aged 45-64 years were followed for a median of 13.4 years and 486 men had experienced a cardiovascular event. In age-adjusted analyses, most inflammatory markers were significantly associated with risk of CHD or CHD/IS, but for IS associations were weaker. On multivariable analyses, including conventional risk factors, associations of serum viscosity, alpha2-macroglobulin and leucocyte count became non-significant for CHD and CHD/IS, while no inflammatory marker retained a significant association with risk of IS. In contrast, IL-6 retained a significant association with CHD and CHD/IS and, after adjustment for IL-6, hazard ratios for downstream inflammatory markers were attenuated to non-significance.
  
  
  CONCLUSIONS
  These findings suggest that IL-6 may play a role in mediating the associations of circulating inflammatory markers with risk of CHD in men. Further studies are required to assess whether this is also the case for risk of IS, and for CHD/IS in women.
authors.affiliation: Department of Epidemiology and Public Health, Queen's University, Belfast, UK.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Patterson
authors.forename: Anne E
authors.initials: AE
authors.lastname: Smith
authors.forename: John W G
authors.initials: JW
authors.lastname: Yarnell
authors.forename: Ann
authors.initials: A
authors.lastname: Rumley
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.forename: Gordon D O
authors.initials: GD
authors.lastname: Lowe
mesh_terms: D015415:Biomarkers / Q000097:blood; D001809:Blood Viscosity; D002097:C-Reactive Protein / Q000378:metabolism; D003327:Coronary Disease / Q000097:blood* / Q000209:etiology; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000097:blood; D020521:Stroke / Q000097:blood* / Q000209:etiology; D006113:United Kingdom / Q000453:epidemiology; D000511:alpha-Macroglobulins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D000511:alpha-Macroglobulins; D005340:Fibrinogen; D002097:C-Reactive Protein