Impact of COMT Val 108/158 Met and DRD2 Taq1B gene polymorphisms on vulnerability to cigarette smoking of Thai males.

The nicotine in cigarette smoke can stimulate the dopaminergic reward pathways. The catechol O-methyltransferase gene (COMT) and dopamine receptor 2 gene (DRD2) are dopamine-related genes. Genetic polymorphisms in these two genes are potential candidates in determining an individual's predisposition to cigarette smoking. The purposes of this study were to examine the association between two polymorphisms in COMT Val (108/158) Met and DRD2 Taq1B and anthropometric-biochemical parameters and to ascertain the association between these polymorphisms and cigarette smoking. The levels of anthropometric-biochemical parameters were determined. COMT Val (108/158) Met and DRD2 Taq1B polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism technique. With regard to COMT Val (108/158) Met and DRD2 Taq1B polymorphisms, no differences were found in anthropometric-biochemical variables, except for thiocyanate concentration. Smoking status was significantly associated with COMT Val (108/158) Met polymorphism, but not associated with DRD2 Taq1B polymorphism. Logistic regression analysis showed that COMT Val (108/158) Met gene polymorphism, educational status, parental smoking, and alcohol consumption had statistically significant impacts on cigarette smoking. The results suggest that COMT Val (108/158) Met genetic polymorphisms, but not DRD2 Taq1B, may influence susceptibility to cigarette smoking among Thai males.