Endothelial nitric oxide synthase gene single nucleotide polymorphisms and the risk of hypertension: A meta-analysis involving 63,258 subjects.

The endothelial nitric oxide synthase (eNOS) gene plays an important role in regulating vascular tone and blood pressure. Recently, the eNOS G894T and T-786C single nucleotide polymorphisms (SNPs) were intensively studied with regard to their associations with hypertension. However, the results of these studies were inconsistent. Therefore, we conducted the so far largest meta-analysis to better assess the correlations between eNOS SNPs and hypertension. Eligible articles were searched in PubMed, Medline, Embase, Scopus, and CNKI up to April 2016. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to detect any potential associations between eNOS SNPs and the risk of hypertension. A total of 95 case-control studies involving 29,308 hypertension cases and 33,950 healthy controls were analyzed. The overall meta-analysis results showed that eNOS G894T and T-786C SNPs were both significantly associated with the risk of hypertension, the T allele of G894T SNP (G versus T, P < 0.00001, OR = 0.82, 95% CI 0.76-0.89) and C allele of T-786C SNP (T versus C, P = 0.004, OR = 0.92, 95% CI 0.87-0.97) conferred an increased susceptibility to hypertension. Further subgroup analyses yielded similar positive results for G894T SNP in essential hypertension, gestational hypertension, and Asian ethnicity, and that for T-786C SNP in essential hypertension and Asian population. Overall, our findings suggest that eNOS G894T and T-786C SNPs were both significantly correlated with hypertension. Additionally, the T allele of G894T SNP and C allele of T-786C SNP may serve as potential biological markers for hypertension susceptibility in Asians.