EFFECT OF CYP2A6*4 GENETIC POLYMORPHISMS ON SMOKING BEHAVIORS AND NICOTINE DEPENDENCE IN A GENERAL POPULATION OF JAPANESE MEN

OBJECTIVES: Nicotine in cigarettes is metabolized primarily by CYP2A6-catalyzed oxidation. The CYP2A6*4 allele, in which CYP2A6 is a homozygous whole-deletion variant, completely lacks enzyme activity. The aim of this study was to examine the effects of CYP2A6*4 genetic polymorphism on smoking behavior and nicotine dependence in a general population of Japanese men.
METHODS: The subjects were 124 healthy Japanese men who gave informed consent to give saliva samples. The survey items included general information, smoking behaviors and nicotine dependence. The polymerase chain reaction restriction fragment length polymorphism method was used to analyze the genetic polymorphisms of CYP2A6. The subjects were classified into two groups: Group W (CYP2A6*4 absence: *1A/*1A, *1A/*1B and *1B/*1B) and Group D (CYP2A6*4 presence: *1B/*4A, *4A/*4A, *1A/*4A or *1B/*4D, and *1A/*4D). We analyzed the differences in the survey items between the two groups.
RESULTS: There were no significant differences in smoking behaviors between the two groups. However, Group D tended to have less difficulty in refraining from smoking after waking in the morning compared to Group W (p=0.051).
CONCLUSIONS: CYP2A6*4 genetic polymorphisms may not strongly affect smoking behavior but may possibly have an effect on nicotine dependence.