Gene-gene interactions of CYP2A6 and MAOA polymorphisms on smoking behavior in Chinese male population.
OBJECTIVE
Nicotine is the major psychoactive ingredient in tobacco, and is responsible for dependence through the nicotine-stimulated reward pathway mediated by the central dopaminergic system. Consequently, genetic polymorphisms in both nicotine metabolism and dopamine catabolism genes may influence smoking behavior, and interact with each other resulting in risk modulation. In this study, we investigated the association and multilocus gene-gene interactions of cytochrome P450 2A6 (CYP2A6), dopamine beta-hydroxylase (DBH), catechol O-methyl transferase (COMT), and monoamine oxidase A (MAOA) polymorphisms with smoking behavior in a community-based Chinese male population.


METHODS
The polymorphisms were genotyped in 203 current smokers, 66 former smokers, and 102 never smokers. Multivariate logistic regression models and the multifactor dimensionality reduction method were used to analyze the association and multilocus gene-gene interactions.


RESULTS
Statistically significant trends were shown for increased risk of smoking initiation in participants with CYP2A6*1B/CYP2A6*1B genotypes compared with those with CYP2A6*1A/CYP2A6*1A genotypes [odds ratio (OR)=3.5, 95% confidence interval (CI)= 1.5-8.1], and participants with CYP2A6*1/CYP2A6*1 genotypes were at higher risk of smoking initiation (OR=2.4, 95% CI=1.2-4.5) and smoking persistence (OR=4.0, 95% CI=1.5-10.3) than those who have CYP2A6*4C genotypes. Moreover, the best model involved a gene-gene interaction between MAOA and CYP2A6 was characterized by the multifactor dimensionality reduction method (64.11% accuracy, P<0.001), and indicated that carriers of the combined 1460 T/O genotype for MAOA EcoRV and CYP2A6*1/CYP2A6*1 genotypes were at higher risk of smoking (OR=15.4, 95% CI=4.5-52.5).


CONCLUSIONS
These findings suggested a substantial influence of CYP2A6 polymorphism as well as the interaction with MAOA resulting in risk modulation on smoking behavior in Chinese male population.
Tang
Xun
X
Department of Epidemiolgy and Biostatistics, Peking University Health Science Center, Peking, China.
Guo
Song
S
Sun
Hongqiang
H
Song
Xuemei
X
Jiang
Zuonin
Z
Sheng
Lixiang
L
Zhou
Dongfeng
D
Hu
Yonghua
Y
Chen
Dafang
D
D000328:Adult; D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D001519:Behavior / Q000502:physiology; D002681:China; D065637:Cytochrome P-450 CYP2A6; D004843:Epistasis, Genetic / Q000502:physiology*; D008040:Genetic Linkage; D005828:Genetics, Population; D006801:Humans; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000235:genetics*; D011110:Polymorphism, Genetic; D012907:Smoking / Q000235:genetics*; D055815:Young Adult
D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6; D008995:Monoamine Oxidase