Apolipoprotein a5 gene polymorphism and risk for metabolic syndrome: a meta-analysis

Many studies have focused on the association between the apolipoprotein A5 (ApoA5) polymorphism and the risk of metabolic syndrome (MetS). However, these studies drew inconsistent conclusions. The aim of this study was to evaluate the exact association between the ApoA5 polymorphism and MetS in a large-scale meta-analysis. The PubMed, Embase, and Science Citation Index (ISI Web of Science) databases were searched to collect all publications on the association between the ApoA5 polymorphism and MetS. Two common variants of ApoA5 (namely -1131T>C in the promoter region and c.56C>G in the coding region) with the risk of MetS were analyzed. The overall odd ratios (ORs) and 95% confidence intervals (CIs) for -1131T>C (CC+TC) versus TT genotype and c.C56G (GG+GC) versus CC were assessed between the MetS and control group. Subgroup analysis was further performed by ethnicity. The meta-analysis was performed by Stata11.0. Twelve studies from 10 publications were chosen in our meta-analysis. The combined results showed that C allele carriers (CC+TC) of -1131T>C had a significantly higher risk of MetS for the overall (OR=1.32; 95% CI: 1.14-1.53; p=0.000) with moderate heterogeneity (I2=54.9%, p=0.014). Subgroup analysis was further performed according to ethnicity, and the association was still significant in Asians (OR=1.42; 95% CI: 1.25-1.62; p=0.000), but not in white populations (OR=1.25; 95% CI: 0.97-1.61; p=0.087). When analyzing the association between c.C56G and MetS, the G allele carrier (GG+GC) genotype significantly increased the risk of MetS (OR=1.32; 95% CI: 1.15-1.50; p=0.000) in white populations. No significant publication bias was observed in either -1131T>C or c.C56G. Our study suggested that the ApoA5 -1131T>C polymorphism was significantly associated with the risk of MetS in Asians, but not in white populations. However, the c.C56G polymorphism was significantly associated with MetS in white populations.