Association of nicotinic acetylcholine receptor subunit alpha-4 polymorphisms with smoking behaviors in Chinese male smokers

Abstract

Background: It has been reported that the nicotinic acetylcholine receptor subunit α4 gene (CHRNA4) might be associated with smoking behaviors in the previous studies. Up to now, there are few reports on the relationship between CHRNA4 and smoking initiation. In this study, we tried to explore the role of two polymorphisms in CHRNA4 (rs1044396 and rs1044397) in smoking initiation and nicotine dependence in Chinese male smokers.

Methods: Nine hundred and sixty-six Chinese male lifetime nonsmokers and smokers were assessed by the Fagerström test for nicotine dependence (FTND), smoking quantity (SQ) and the heaviness of smoking index (HSI). All subjects were divided into four groups based on their tobacco use history and the FTND scores. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to find two polymorphisms of CHRNA4 in these subjects.

Results: The χ(2) test showed that rs1044396 was significantly associated with smoking initiation (χ(2) = 4.65, P = 0.031), while both rs1044396 and rs1044397 were significantly associated with nicotine dependence (χ(2) = 5.42, P = 0.020; χ(2) = 7.58, P = 0.005). Furthermore, the T-G (3.9%) haplotype of rs1044396-rs1044397 showed significant association with smoking initiation (χ(2) = 6.30, P = 0.012) and the C-G haplotype (58.9%) remained positive association with nicotine dependence (χ(2) = 8.64, P = 0.003) after Bonferroni correction. The C-G haplotype also significantly increased the HSI (P = 0.002) and FTND scores (P = 0.001) after Bonferroni correction.

Conclusion: These findings suggest that CHRNA4 may be associated with smoking initiation and the C-G haplotype of rs1044396-rs1044397 might increase the vulnerability to nicotine dependence in Chinese male smokers.