Association between polymorphism of the G-protein β3 subunit C825T and essential hypertension: an updated meta-analysis involving 36,802 subjects.

PURPOSE The G-protein β3-subunit gene C825T polymorphism (GNB3-C825T) has been reported to be associated with essential hypertension (EH), but results from previous studies are conflicting. The present study aimed at investigating the association between this polymorphism and risk of EH using a meta-analysis on the published studies. MATERIALS AND METHODS PubMed, Embase, CBM (China Biological Medicine Database), Wanfang and VIP databases were searched to identify eligible studies published in English and Chinese before March 2013. Data were extracted using standardized methods. The association was assessed by the odds ratio (OR) with 95% confidence intervals (CI). Begg's test was used to measure publication bias. RESULTS A total of 40 case-control studies containing 16,518 EH patients and 20,284 controls were involved in this meta-analysis. Overall, a significant association was found between GNB3 C825T polymorphism and risk of EH when all studies were pooled with a random-effects model for T versus C (OR=1.09, 95% CI: 1.04-1.19). In the subgroup analysis, the same association was found in overall Caucasian (T versus C, OR=1.16, 95% CI 1.08-1.24) and Chinese populations (TT versus CC, OR=1.23, 95% CI 1.06-1.57). No associations were detected between GNB3-C825T and the risk of EH overall in Asian and Japanese people. CONCLUSIONS Meta-analysis results suggest that the GNB3-C825T polymorphism is associated with risk of EH in the overall population, the Caucasians and the Chinese. The effect of the variants on the expression levels and the possible functional role of the variants in EH should be addressed in further studies.