Association of functional catechol O-methyl transferase (COMT) Val108Met polymorphism with smoking severity and age of smoking initiation in Chinese male smokers.
BACKGROUND
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Guo
Song
S
Institute of Mental Health, Peking University, Beijing, 100083, China.
Chen
Da Fang
DF
Zhou
Dong Feng
DF
Sun
Hong Qiang
HQ
Wu
Gui Ying
GY
Haile
Colin N
CN
Kosten
Therese A
TA
Kosten
Thomas R
TR
Zhang
Xiang Yang
XY
D000328:Adult; D000367:Age Factors; D000368:Aged; D044466:Asian People / Q000235:genetics*; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002681:China; D015331:Cohort Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D016015:Logistic Models; D008297:Male; D008715:Methionine; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012907:Smoking / Q000235:genetics* / Q000378:metabolism; D016540:Smoking Cessation; D014029:Tobacco Use Disorder / Q000201:enzymology / Q000235:genetics*; D014633:Valine
D008715:Methionine; D002394:Catechol O-Methyltransferase; D014633:Valine