title: A meta-analysis of interleukin-6 promoter polymorphisms on risk of hip and knee osteoarthritis.
abstract: OBJECTIVE
  Interleukin-6 is a pro-inflammatory cytokine involved in the pathogenesis of osteoarthritis (OA). We investigated the role of two single nucleotide polymorphisms (SNPs) mapping to the promoter of the IL-6 gene on genetic susceptibility to hip and knee OA.
  
  
  METHODS
  The -174G/C (rs1800795) and -597G/A (rs1800797) SNPs, implicated in the literature in risk of hip and hand OA, were genotyped in 2511 controls, 1101 hip OA cases and 1904 knee OA cases from four cohorts from the UK and Estonia. Data were analysed in conjuntion with published data on rs1800797 from the Genetics of OA and Lifestyle study (UK) on 791 controls, 1034 knee and 997 hip OA cases and rs1800795 data on 75 hip OA cases and 96 controls from Italy. Cases included both radiographic OA only and radiographic and symptomatic OA. Fixed and random-effects meta-analysis models were tested.
  
  
  RESULTS
  No significant association was found with hip OA or knee OA with either SNP nor with the haplotypes formed by them. For individual SNPs the smallest P-value for hip OA was observed using a random-effects model for rs1800795 OR(Gallele)=1.066 (95% CI 0.89-1.28) P<0.49, and significant heterogeneity between cohorts (I(2)=65%, P<0.034) was detected. For knee OA the smallest P-value was seen for rs1800797 OR(Aallele)=1.055 (95%CI 0.98-1.12) P<0.18, no significant heterogeneity was observed (I(2)=0%, P<0.68).
  
  
  CONCLUSIONS
  Our data do not support a role for the -174 and -597 IL-6 promoter polymorphisms in genetic susceptibility to knee or hip OA in Caucasian populations.
authors.affiliation: Department of Twin Research, St. Thomas' Hospital Campus, Kings College London School of Medicine London, UK. ana.valdes@kcl.ac.uk
authors.forename: A M
authors.initials: AM
authors.lastname: Valdes
authors.forename: N K
authors.initials: NK
authors.lastname: Arden
authors.forename: A
authors.initials: A
authors.lastname: Tamm
authors.forename: K
authors.initials: K
authors.lastname: Kisand
authors.forename: S
authors.initials: S
authors.lastname: Doherty
authors.forename: E
authors.initials: E
authors.lastname: Pola
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.forename: A
authors.initials: A
authors.lastname: Tamm
authors.forename: K R
authors.initials: KR
authors.lastname: Muir
authors.forename: I
authors.initials: I
authors.lastname: Kerna
authors.forename: D
authors.initials: D
authors.lastname: Hart
authors.forename: F
authors.initials: F
authors.lastname: O'Neil
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: T D
authors.initials: TD
authors.lastname: Spector
authors.forename: R A
authors.initials: RA
authors.lastname: Maciewicz
authors.forename: M
authors.initials: M
authors.lastname: Doherty
mesh_terms: D015331:Cohort Studies; D005787:Gene Frequency; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D015207:Osteoarthritis, Hip / Q000235:genetics*; D020370:Osteoarthritis, Knee / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D012307:Risk Factors
chemical_list: D015850:Interleukin-6