The effect of PPARG gene polymorphisms on the risk of coronary heart disease: a meta-analysis

The peroxisome proliferator-activated receptor-γ (PPARG) is a member of the nuclear hormone receptor superfamily that has attracted considerable attention as a candidate gene for coronary heart disease (CHD) based on its function as a key factor involved in the regulation of lipid and glucose metabolism. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the PPARG polymorphisms and CHD. However, these studies have yielded contradictory results. To derive a more precise estimation of the relationship, a meta-analysis of 33 studies including a total of 12,340 cases and 17,471 controls on 3 PPARG polymorphisms (Pro12Ala, C161T and C1431T) was performed. In a combined analysis, the summary per-allele odds ratio for CHD was 1.02 (95 % CI: 0.93-1.13), 0.86 (95 % CI: 0.72-1.02), and 0.92 (95 % CI: 0.74-1.16) for PPARG 12Ala, 161T and 1431T alleles, respectively. No significant results were observed under dominant or recessive genetic models for these polymorphisms in almost all comparisons. In the stratified analyses according to ethnicity, sample size, CHD endpoints and HWE status, no evidence of any gene-disease association was obtained. Our results suggest that the Pro12Ala, C161T and C1431T polymorphisms of PPARG gene are not associated with CHD susceptibility.