The association between polymorphism of the BDNF gene and cigarette smoking in the Iranian population.

BACKGROUND: Cigarette smoking remains a serious public health problem. Environmental and genetic factors both play critical roles in the process of cigarette smoking. We aimed to investigate the associations between single nucleotide polymorphisms (SNP) in the BDNF gene and cigarette smoking in the Iranian population.

METHODS: We conducted a case-control study. In total, 932 case and control subjects aged > 15 years were recruited in the present study in a simple random manner, including 523 lifetime cigarette smokers, 466 cigarette smokers within a 12-month period, 409 never cigarette smokers in their lifetime and 466 never cigarette smokers within a 12-month period. The rs6265 SNP genotypes were determined by a polymerase chain reaction followed by restriction fragment length polymorphism. To examine the association of smoking with the BDNF gene polymorphism, odds ratios (OR) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression adjusting for age and sex.

RESULTS: In total, 932 participants (758 males and 174 females) were selected. Using a chi-squared test, we found that rs6265 with OR = 1.41 and 95% CI = 1.07-1.87 (p = 0.009) and OR = 1.41 and 95% CI = 1.08-1.85 (p = 0.008) in the BNDF was associated with an increased odds of lifetime cigarette smoking and cigarette smoking within a 12-month period, respectively. Also, the allele "A" of rs6265 in BDNF had a significant elevating effect for cigarette smoking in a recessive model (p < 0.05).

CONCLUSIONS: These results suggest that polymorphisms of BDNF play an important role in lifetime cigarette smoking and cigarette smoking within a 12-month period of susceptibility in the Iranian population.