Association of Interleukin-6 Genetic Polymorphisms and Environment Factors Interactions with Coronary Artery Disease in a Chinese Han Population.

OBJECTIVES: To investigate the influence of IL-6 single nucleotide polymorphisms (SNPs), additional gene-gene and gene-environment interactions on coronary artery disease (CAD) risk.

METHODS: A total of 751 participants (429 CAD patients and 322 controls) were recruited in this study. Logistic regression analysis was conducted to evaluate the association of IL-6 SNPs with CAD risk and generalized multifactor dimensionality reduction (GMDR) was performed to investigate the best interaction combinations for gene-gene and gene-environment interactions.

RESULTS: CAD risk is significantly higher in carriers of C allele of the rs1800795 polymorphism than those with GG genotype (CC + CG versus GG, adjusted OR (95%CI) = 2.07 (1.56-2.86), p < 0.001). GMDR analysis revealed rs1800795 was significantly interacted with tobacco smoking and alcohol drinking in two-locus model (p < 0.0010). Current smokers with CC or CG of rs1800795 genotype have the highest CAD risk, OR (95%CI) = 3.22 (2.45-3.94) and current drinkers with CC or CG of rs1800795 genotype have the highest CAD risk, OR (95%CI) = 3.17 (2.20-4.24).

CONCLUSION: The C allele of rs1800795 within IL-6 gene promoter, rs1800795-tobacco smoking and rs1800795-alcohol drinking interaction were all associated with increased CAD risk.