title: Interleukin-6 serum levels and genotypes influence the risk for myocardial infarction.
abstract: OBJECTIVE
  Several studies show that the inflammatory component in atherosclerosis may contribute to increased risk for cardiovascular disease (CVD). Interleukin-6 (IL-6) is a key pro-inflammatory and immune-stimulatory cytokine of presumed importance for CVD and the metabolic syndrome.
  
  
  RESULTS
  In this case-control study, 1179 surviving myocardial infarction (MI) cases and 1528 healthy controls were genotyped for three IL-6 promoter SNPs, and serum concentrations of IL-6 and C-reactive protein (CRP) were measured. In men, MI risk assessed as odds ratios (OR) was higher with increasing IL-6 levels, with the highest compared to the lowest IL-6 quartiles giving an OR of 2.7 [95% CI 1.7-4.4]. The ORs were independent from the effects of elevated CRP which were associated with modest MI risks (OR = 1.6 [95% CI 1.0-2.5]). Also, synergistic interactions between high IL-6 levels and hypercholesterolaemia further increased MI risk estimates. The -174C allele was associated with lower serum-insulin levels among male controls but did not significantly influence MI risk or IL-6 levels.
  
  
  CONCLUSIONS
  Elevated IL-6 levels are important risk markers for MI in men, the risk being further enhanced through synergistic interaction with hypercholesterolaemia. The data provide no clear evidence that polymorphisms in the IL-6 promotor region play a significant role in the pathogenesis of MI, and it remains to be further evaluated whether or not the -174C allele is of relevance for insulin resistance.
authors.affiliation: Division of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institute, P.O. Box 210, S-171 77, Stockholm, Sweden. anna.bennet@imm.ki.se
authors.forename: Anna M
authors.initials: AM
authors.lastname: Bennet
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Prince
authors.forename: Guo Zhong
authors.initials: GZ
authors.lastname: Fei
authors.forename: Louise
authors.initials: L
authors.lastname: Lyrenäs
authors.forename: YiHui
authors.initials: Y
authors.lastname: Huang
authors.forename: Björn
authors.initials: B
authors.lastname: Wiman
authors.forename: Johan
authors.initials: J
authors.lastname: Frostegård
authors.forename: Ulf de
authors.initials: Ud
authors.lastname: Faire
mesh_terms: D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D015994:Incidence; D015850:Interleukin-6 / Q000097:blood* / Q000235:genetics; D008297:Male; D009203:Myocardial Infarction / Q000097:blood* / Q000453:epidemiology* / Q000235:genetics; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D015996:Survival Rate
chemical_list: D005819:Genetic Markers; D015850:Interleukin-6; D002097:C-Reactive Protein