Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) null polymorphisms and the risk of hypertension: a meta-analysis.
BACKGROUND
Some studies have recently focused on the association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and hypertension; however, results have been inconsistent.


OBJECTIVE
In order to drive a more precise estimation, the present systematic review and meta-analysis is performed to investigate the relationship between the GSTM1 and GSTT1 null polymorphisms and hypertension.


METHODS
Eligible articles were identified by a search of several bibliographic databases for the period up to August 17, 2013. Odds ratios were pooled using either fixed-effects or random-effects models.


RESULTS
Regarding the GSTM1 null/present genotype, 14 case-control studies were eligible (2773 hypertension cases and 3189 controls). The meta-analysis revealed that it might present a small increased risk for hypertension, although the effect was not statistically significant (odd ratio (OR) = 1.16, 95% confidence interval (CI): 0.96, 1.40; P = 0.002, I2 = 59.8%). Further subgroup analysis by ethnicity and control source suggested that the association was still not significant. Thirteen case-control studies were eligible for GSTT1 (2497 hypertension cases and 3078 controls). No statistically significant association was observed between the GSTT1 null genotype and hypertension risk (OR = 1.14, 95% CI: 0.85, 1.53; P = 0.000, I2 = 80.3%). Furthermore, stratification by ethnicity and control source indicated no association between the GSTT1 null genotype and hypertension risk. We further confirmed the association by sensitivity analysis. No publication bias was detected.


CONCLUSIONS
This meta-analysis suggests that the GSTM1 and GSTT1 null polymorphisms are not associated with the risk of hypertension. Future large well-designed epidemiological studies with individual information, lifestyle factors, and environmental factors are warranted to validate the present findings.
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Beihai
B
Ge
Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Yadong
Y
Song
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Yi
Y
Zhang
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Xiaowen
X
Liu
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Yuxiang
Y
Wen
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Xiaomei
X
Guo
D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic
D005982:Glutathione Transferase; C413545:glutathione S-transferase T1