Meta-analysis of the association between IL-18 rs 1946518 , rs 187238 polymorphisms and coronary artery diseases

Coronary artery disease (CAD) is one of the major health problems worldwide. The polymorphisms of Interleukin-18 (IL-18), including rs1946518 (-607 C/A) and rs187238 (-137 G/C), have been found to be probably associated with the risk of CAD. However, the results were inconsistent and controversial. To determine the association between IL-18 promoter rs1946518 and rs187238 polymorphisms with CAD, we conducted the meta-analysis of all relevant studies cited in Pubmed, Embase, CENTRAL, CBM and CNKI before 6 July 2016. A total of 7 studies, including 2636 cases and 1664 controls, were identified for the meta-analysis. The results showed that the CC genotype of rs1946518 was associated with a significantly higher risk of CAD in allelic model (OR = 1.38), homozygous model (OR = 2.06), heterozygous model (OR = 1.44) and dominant model (OR = 1.56) in the overall analysis. But in subgroup analysis by ethnicity, the CC of rs1946518 had no significant associations with risk of CAD in Caucasians. The results also showed a significant higher risk of CAD in GG genotype of rs187238 in heterozygous model (OR = 1.45) and dominant model (OR = 1.19) in the overall analysis. Subgroup analysis by ethnicity discovered GG genotype of rs187238 was associated with a significantly higher risk of CAD in all genotypes in Asian, while only in heterozygous model in Indian. In conclusion, our results suggested higher risks of CAD for CC of rs1946518 and GG of rs187238 in Asian. However, the results of this meta-analysis are hypothesis-generating results which should be interpreted with caution because of the heterogeneity and publication bias among study designs.