RESUMO
BACKGROUND: Essential hypertension (EH) results from a complex interaction between environmental factors and an individual's genetic background. AIM: To assess the relationship between polymorphisms in GSTM1 and GSTT1 and the risk of EH. SUBJECTS AND METHODS: A multiplex-PCR was used to identify the genotypic profiles of GSTM1 and GSTT1 in 160 patients and 210 controls. RESULTS: The frequency of GSTM1-null genotype was higher in patients younger than 61 years when compared to those over 61 years. Interestingly, GSTT1-null was significantly associated with the risk of EH (OR 4; 95% CI 2.6-6.3; p < 0.0001). While GSTM1-null showed no trend (OR 0.7; 95% CI 0.5-1.1, p = 0.12). Individuals carrying the combined GSTT1-null/GSTM1-null were 2.4 times more at risk for hypertension compared to those harbouring the combined GSTT1-present/GSTM1-present genotype (OR 2.4; 95% CI 1.3-4.4; p = 0.005). Additionally, the presence of the combined GSTT1-null/GSTM1-present was associated with an increased risk of EH compared to GSTT1-present/GSTM1-present carriers (OR 6.75; 95% CI 3.4-13.2; p < 0.0001). CONCLUSION: This study showed that the GSTT1-null alone or in interaction with GSTM1-present or GSTM1-null was associated with a higher risk of hypertension. Moreover, the GSTM1-null seems to be associated with the age of onset of hypertension.