The Association between DNA Polymorphisms and Smoking Cessation in Korean Smokers

ABSTRACT

BACKGROUND: Recent research demonstrates a strong association between smoking-related behaviors and genetic variation. We investigated the clinical features and genetic effects of dopamine receptors and a serotonin transporter on smoking cessation in Koreans. METHODS: Smokers (n=51) wanting to quit smoking were included as the study population. They were genotyped for polymorphisms in dopamine D2 receptor (DRD2) (TaqI and -141C), dopamine D4 receptor (DRD4), and a serotonin transporter (5-HTT). We defined abstinence as stopping smoking at six months after enrollment. RESULTS: Eighteen patients (35.3%) stopped smoking at six months. The abstinence group had a higher rate of alcohol use whereas the non-abstinence group had more coughing. However, there were no significant differences in average smoking rate, starting age of smoking, gender, nicotine dependence, and forced expiratory volume in one second between the two groups. As for the genes in the dopamine pathway, the polymorphisms of DRD2 TaqI (A1 allele) and DRD2 -141C (Ins C allele) were not genotypically different between the two groups (P=0.245 and 0.409, respectively). The genetic variation in the DRD4 variable number of tandem repeats (VNTR) also showed a similar distribution in the two groups. Regarding the polymorphisms of 5-HTT, there was no difference in the long allele between the two groups (P=0.852). CONCLUSIONS: This study suggests that the genetic variations of DRD2 TaqI, DRD2 -141C, DRD4 VNTR, and 5-HTT might have little influence on smoking cessation in Korean smokers.