No association between interleukin-18 levels and risk of cardiovascular disease: A Mendelian randomization study

Objective In this study, Mendelian randomization method was used to determine whether there was a causal association between inflammatory cytokine IL-18 and cardiovascular disease risk. Methods We performed a meta-analysis to evaluate the association between IL-18-137G/C and -607C/A polymorphisms and phenotype of IL-18 levels, and also the risks of CVD. All the literatures were searched before September 30, 2019. The logistic regression and linear regression were used to evaluate between IL-18 level and the risk of CVDs. Result Twelve eligible articles of the association between IL-18-137G/C and CVD risks and 8 eligible literatures related to IL-18-607C/A and CVD risks; 2 qualified literatures of the association between IL-18 SNPs and IL-18 levels and 4 eligible literatures related to IL-18 levels and CVD risks. Data of 4 literatures on the correlation between IL-18 level and CVD were summarized. Compared with patients with CVD, the mean of IL-18 level in the normal group was significantly decreased by 50.844 pg/ml (P < 0.05). But the association between IL-18-137G/C, IL-18-607C/A and CVD were not significant (P > 0.05), and the association between IL-18-607C/A and IL-18 level was also not significant (P > 0.05), Mendelian randomization study was failed to prove the association between IL-18 level and CVD risk. Conclusion This study does not support a causal association between IL-18 level and the risks of CVD.