Association between CYP2A6 genotypes and smoking behavior in Lebanese smokers

Introduction: With the absence of effective reinforcement of tobacco control laws in the country, the Lebanese population has been vulnerable to the health burden of smoking. Smoking and quitting behaviors are influenced by genetic factors, mainly CYP2A6 polymorphisms. To date, the assessment of the genetic profile and its effect on the behavior of Lebanese smokers has not yet been studied. The aim of this study was to determine the CYP2A6 polymorphisms and its relation to smoking and quitting behavior in a cohort of Lebanese smokers. Methods: Healthy adult Lebanese smokers were recruited from the American University of Beirut and its Medical Center. Their nicotine metabolite (NM) levels and CYP2A6 alleles (2, 4, 9 and 12) were determined. The smoking behavior, Nicotine Dependence Score (NDS) and quitting behavior of the participants were assessed after filling a "smoking assessment questionnaire". Results: 53 healthy adult smokers participated in our study (M: F= 4:1, median age= 38.47 +/- 14.15 years). Mutated CYP star 2 was present in 33.9% (18/53 cases), CYP star 4 in 11.3% (6/53 cases), CYP* 9 in 100% (53/53 cases) and CYP star 12 in 86.7% (46/53 cases). Slow metabolizers constituted 90.6% of our group while 9.4% were intermediate metabolizers. Slow metabolizers smoked a smaller number of cigarettes per day (CPD) (median= 15 CPD vs 25 CPD) and had higher NM levels (median= 23 ng/mL vs 10 ng/mL or undetectable) than intermediate metabolizers. A statistically significant correlation with NDS and quitting behavior was not found in either group. Conclusion: In this first study from Lebanon, a unique distribution of CYP2A6 alleles (high prevalence of CYP2A6(star)9 and CYP2A6(star)12) was detected. In accordance with previously published data, slow metabolizers smoked a lower number of CPD and had higher NM levels in their serum. Larger studies are required to fully elucidate the CYP2A6 polymorphisms of Lebanese smokers and include them in personalized smoking cessation programs.