The C161T polymorphism in the peroxisome proliferator-activated receptor gamma gene (PPARγ) is associated with risk of coronary artery disease: a meta-analysis.

The researches attempting to associate the PPARγ C161T polymorphism with coronary artery disease (CAD) yielded complicated and contradictory results. We aimed for more precise estimate of the relationship and conducted a comprehensive meta-analysis. Publications written in English or Chinese were screened in MEDLINE, Embase, CNKI, Wanfang and CBM. Data on 11 studies including 3,020 cases and 2,853 controls were extracted. A random-effects model was available to synthesize the inconsistent outcomes of the individual studies, while addressing between-study heterogeneity and publication bias. The PPARγ C161T polymorphism followed Hard-Weinberg Equilibrium for all studies (P > 0.05).Overall, there was no evidence for a significant association under all genetic models but with distinct heterogeneity (T vs. C: P = 0.29, OR = 0.91, 95 %CI 0.77-1.08, P heterogeneity = 0.004, I (2) = 61.2 %). However, in the subgroup analysis by ethnicity, the T allele carriers showed a prominent 26 % risk reduction of CAD among Chinese (dominant genetic model: P = 0.03, 95 %CI 0.57-0.97, P heterogeneity = 0.03, I (2) = 56.1 %). After dividing into population source, the significance of CAD risk reduction was strengthened in hospital-based studies (allele comparison: P = 0.04, OR = 0.82, 95 %CI 0.67-1.00, P heterogeneity = 0.04, I (2) = 52.5 %; dominant model: P = 0.01, OR = 0.73, 95 %CI 0.57-0.92, P heterogeneity = 0.05, I (2) = 50.8 %). There was no obvious publication bias verified in the method of funnel plot and Egger's linear regression test (t = -0.11, P = 0.913). Taken together, our results revealed the PPARγ C161T polymorphism might play a moderate protective effect on developing CAD among Chinese, but not among Caucasians.