Background: Recent studies suggest that the common variant in the glutathione S-transferase (GST) M1 (GSTM1) and T1 (GSTT1) gene is associated with the risk of smoking-related coronary artery disease (CAD). Intra-ethnic as well as inter-ethnic differences are known to impact the frequencies of GST gene polymorphisms, thus influencing its interactive effect with tobacco smoking on CAD risk. The aim of the present study was to evaluate the interaction of the genetic polymorphisms of GSTM1 and GSTT1 with cigarette smoking and the risk of CAD in a Chinese population.
Methods: We conducted a study with 277 CAD patients and 277 controls matched by age and sex to examine the prevalence of GSTM1 and GSTT1 polymorphism in CAD.
Results: We found that homozygous deletion of GSTM1 had a frequency of 32.1% among patients with CAD and 21.3% among those without CAD (p=0.004). The frequency of the GSTT1(null) genotype was 27.8% among the patients with CAD and 19.1% among CAD-free subjects (p=0.016). Patients who smoked having both the wild-type genotypes of GSTM1 and GSTT1 were protected from developing coronary heart disease (p<0.001). Moreover, smokers with combined GSTM1(null)GSTT1(null) genotypes had a significantly higher number of stenosed vessels than those with the positive genotype (p=0.02).
Conclusions: Our results suggest that GST polymorphisms may be a susceptibility factor to smoking-related CAD in the Chinese population.