The MAOA VNTR polymorphism and smoking behavior in Brazilian males

Abstract

Introduction: Tobacco smoking represents the leading preventable cause of morbidity and mortality in adults. Nicotine is responsible for tobacco addiction and is known to elevate brain dopamine, leading to feelings of pleasure and reward. The MAOA enzyme is responsible for degrading dopamine. It is known that a polymorphism in the promoter region of the MAOA gene has been implicated in smoking behavior. In this study, we investigated the association between the MAOA VNTR polymorphism and smoking behavior in Brazilian males. Methods:A cross-sectional study was conducted with 121 Brazilian males over 18 years of age. The polymorphism was genotyped using PCR. Multiple logistic regression were used to verify the association of MAOA gene polymorphisms with smoking status. Results:We not found significant association between the MAOA polymorphism and smoking status. Likewise, no association of the VNTR polymorphism with elements of smoking behavior, such as smoking duration, smoking initiation, relapses, smoking cessation, and degree of nicotine dependence, was observed. Conclusions:In conclusion, no association was observed between the MAOA polymorphism, smoking status and smoking behavior in population of Brazilian males studied. Further studies with larger sample sizes will be needed to elucidate these issues.

Genetic variability in the neurobiology of nicotine dependence: effects on smoking behavior

“…Similarly, the 4-repeats allele has been associated with higher FTND scores and a higher degree of dependence in women 70 . However, the data are not conclusive, since these findings have not been confirmed by other studies 66,93,103 .…”

“…One repetition polymorphism, the MAOA VNTR of the promoter region of the gene, which consists of 2 to 5 repetitions of a sequence of 30 base pairs, is related to smoking. Two alleles containing 3 and 4-repeats are most common 60,66,70,71,93,102,103 . The 4-repeats allele has been associated with a greater number of cigarettes consumed, compared to the 3-repeats allele, in Caucasian men with alcohol and tobacco dependence 71 .…”