Association of functional catechol O-methyl transferase (COMT) Val108Met polymorphism with smoking severity and age of smoking initiation in Chinese male smokers.
ABSTRACT Catechol-O-methyltransferase (COMT) is an enzyme involved in the degradation and inactivation of the neurotransmitter dopamine, which is important in mediating drug reward such as nicotine in tobacco smoke. Different COMT alleles encode enzyme whose activity varies from three- to fourfold that may affect dopamine levels and alter subjective effects of nicotine. Recent evidence also suggests that a COMT polymorphism may be especially important in determining an individual's predisposition to developing nicotine dependence.
We studied the COMT Val108Met polymorphism in a male population of 203 current smokers, 66 former smokers, and 102 non-smokers. The age-adjusted odds ratios were estimated by multiple logistic regression models.
The results showed no significant association of the COMT Val108Met with initiation, persistent smoking, or smoking cessation. However, current smokers with the Met allele had significantly higher Fagerstrom Test for Nicotine Dependence scores (7.5 +/- 2.1 vs 6.8 +/- 1.8, p = 0.018) and started smoking significantly earlier (18.4 +/- 4.9 vs 20.1 +/- 5.9 years, p = 0.036).
These results suggest that the COMT Val108Met polymorphism may not influence smoking status in a Chinese male population but may influence the age at which smoking started and smoking severity among smokers. However, the findings must be regarded as preliminary because of the relatively small sample size and marginal associations and should be replicated in a larger cohort.
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ABSTRACT: Cigarette smoking behavior may be influenced by catechol-O-methlyltransferase (COMT), dopamine beta-hydroxylase (DBH), and monamine oxidase-A (MAO-A), genes that play roles in dopamine metabolism. The association between common polymorphisms of these genes and smoking behavior was assessed among 10,059 Caucasian volunteers in Washington County, MD in 1989. Age-adjusted logistic regression was used to measure the association between variants of these single nucleotide polymorphisms and smoking initiation and persistent smoking. Overall, no association was seen between each genotype and smoking behavior. However, among younger (<54 years) women, the COMT GG genotype was positively associated with smoking initiation (OR=1.3; 95% CI: 1.0 1.5), and the MAO-A TT genotype was inversely associated with persistent smoking (OR=0.7; 95% CI: 0.4, 1.0). Men who smoked fewer than 10 cigarettes per day were more likely to be persistent smokers if they had the COMT GG (OR=1.7; 95% CI: 1.0, 2.9) or the DBH GG (OR=1.6; 95% CI: 1.0, 2.5) genotypes. Overall the results of this large community-based study do not provide evidence to support the presence of important associations between variants of COMT, DBH, or MAO-A and smoking initiation or persistent smoking.Preventive Medicine 07/2008; 47(1):116-22. DOI:10.1016/j.ypmed.2008.03.013 · 2.93 Impact Factor
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ABSTRACT: Some recent studies show an association between a functional polymorphism of BDNF gene (Val66Met) and the susceptibility to nicotine dependence and we hypothesized that this polymorphism was associated with smoking in both schizophrenia patients and healthy controls. The BDNF Val66Met gene polymorphism was genotyped in 690 chronic male schizophrenia patients (smoker/nonsmoker= 522/169) and 628 male controls (smoker/nonsmoker=322/306) using a case–control design. Nicotine dependence (ND) was assessed by the cigarettes smoked per day (CPD), the Heaviness of Smoking Index (HSI), and the Fagerstrom Test for ND (FTND). Patients also were rated on the Positive and Negative Symptom Scale (PANSS). The results showed no significant differences in BDNF Val66Met genotype and allele distributions between the patients and healthy controls or between smokers and nonsmokers in either patients or healthy controls alone. In patient groups, however, the smokers with the Met allele had significantly higher HSI scores (Met/Met: 2.8±1.7 vs. Met/Val: 2.2±1. 7 vs.Val/Val: 2.0±1.6, p<0.01) and a trend toward a significantly higher FTND score (p=0.09) than those with the Val/Val genotype. In addition, the smokers showed significantly lower PANSS negative symptom and total scores, longer duration of illness and more hospitalizations (all p<0.05). In the control group, the smokers with the Met allele started smoking significantly earlier than those with the Val/Val genotype (both p<0.05). These results suggest that the BDNF Val66Met polymorphism may affect a smoker’s response to nicotine in both schizophrenia and healthy controls from a Chinese Han population, but with differential effects in different aspects of smoking behaviors.Journal of Psychiatric Research 10/2014; 60. DOI:10.1016/j.jpsychires.2014.09.023 · 4.09 Impact Factor