Association between the angiotensinogen gene T174M polymorphism and hypertension risk in the Chinese population: a meta-analysis

No consensus has been reached on the association between the angiotensinogen gene polymorphism T174M and hypertension risk in the Chinese population. We conducted a meta-analysis to systematically pursue their possible association. Case-control studies in the Chinese and English publications were identified by searching the MEDLINE, EMBASE, CBM, CNKI, Wanfang and VIP databases. The fixed-effects model and the random-effects model were applied for dichotomous outcomes to combine the results of the individual studies. After this, we selected 16 studies that met the inclusion criteria. In total, the selected studies contributed a study population containing 3828 hypertensive patients and 3251 normotensive controls. We found no statistical association between the T174M polymorphism and hypertension risk in all subjects, in a Han Chinese subgroup or in non-Han Chinese minorities. However, a statistically significant association was observed between the T174M polymorphism and a hypertensive group (systolic blood pressure ≥160 mm Hg and/or diastolic blood pressure ≥95 mm Hg) in the dominant genetic model (MM+MT vs. TT: P=0.03, odds ratio=1.71, 95% confidence interval 1.07-2.74, P(heterogeneity)=0.27, I(2)=24%, fixed-effects model). No evidence of publication bias was observed. More studies, especially studies stratified for different stages of hypertension, should be performed in the future to fully examine this question. Studies investigating gene-gene interactions, gene-environment interactions, as well as their mutual interactions will also be important.