Association of Circulating and Aortic Zinc and Copper Levels with Clinical Abdominal Aortic Aneurysm: a Meta-analysis

It remains obscure whether circulating aortic zinc (Zn) and copper (Cu) levels are associated with the progress of human abdominal aortic aneurysms (AAA). Therefore, we conducted a meta-analysis to explore this relationship. A literature search on circulating and aortic zinc and copper levels and AAA patients was conducted using online databases including PubMed, Embase, and Cochrane up to March 20, 2019. To compare Zn and Cu concentrations in AAA patients with those in aortic occlusive disease (AOD) patients or healthy aorta donors or healthy blood donors, pooled weighted mean difference (WMD) and its 95% confidence interval (CI) were calculated. Subgroup analysis, sensitivity analysis, and meta-regression analysis were applied to explain the heterogeneity and evaluate the robustness of combined results. A total of 10 cross-sectional studies, including 252 cases and 304 controls, were used for meta-analysis. We found that circulating zinc and Zn/Cu ratio in AAA patients were significantly lower [WMD (95%CI): - 2.23 (- 4.10, - 0.36); - 0.18 (- 0.31, - 0.05), respectively] than those in non-AAA patients. Similarly, aneurysmal aorta had significantly lower zinc levels and Zn/Cu ratio [WMD (95%CI): - 9.22 (- 15.37, - 3.07); - 6.46 (- 10.14, - 2.77), respectively] than those in control group. No difference in circulating or aortic copper levels was noted between AAA patients and control group [WMD (95%CI): - 0.24 (- 2.09, 1.61); 0.30 (- 0.01, 0.61) , respectively]. Our meta-analysis suggests that zinc levels and Zn-Cu ratio, but not copper levels, may influence aneurysmal progress of AAA.