BDNF Val66Met polymorphism and serum concentrations of BDNF with smoking in Thai males.

Many studies have suggested that brain-derived neurotrophic factor (BDNF) is involved in the reward system of addiction, and that nicotine may induce alterations in BDNF gene expression and its protein level within the mesocorticolimbic system. We investigated the BDNF levels and biochemical-hematological parameters of smoker and non-smoker groups, and examined the association of the Val66Met BDNF gene polymorphism with BDNF serum levels and cigarette smoking. The study sample comprised 311 Thai volunteers (200 smokers; 111 non-smokers). The levels of serum BDNF and biochemical-hematological parameters were determined. The Val66Met BDNF polymorphism was genotyped by the polymerase chain reaction-restriction fragment length polymorphism technique. The smoker group had significantly higher serum BDNF levels than the non-smoker group (8.3 vs 6.5 ng/mL, P < 0.05). BDNF concentrations correlated positively with hemoglobin, hematocrit, red blood cell count, white blood cell count, platelet count, number of cigarettes smoked, and thiocyanate level (P < 0.05). No association was found between the BDNF Val66Met genotype and the serum BDNF level. The BDNF Val66Met polymorphism was not significantly associated with the smoking status of the Thai males in this study. Cigarette smoking may be one factor that determines the serum BDNF level, but the BDNF Val66Met polymorphism probably does not influence susceptibility to smoking among Thai males.