Increased plasma brain-derived neurotrophic factor levels in chronic smokers following unaided smoking cessation

Recent animal studies have suggested an association between nicotine And alterations in brain-derived neurotrophic factor (BDNF) expression levels. However, the role of BDNF in humans with nicotine dependence has not yet been investigated. In this study, we explored the differences in the plasma BDNF levels of chronic smokers and healthy nonsmokers, and we investigated the changes in plasma BDNF levels in chronic smokers following unaided smoking cessation. Forty voluntary participants (20 smokers and 20 nonsmokers) were enrolled in this study. We measured the plasma BDNF levels at baseline (both groups) and at the end of the two-month study period (smoker group only) using an enzyme-linked immunosorbent assay. A total of 12 smokers (60.0%) completed the two-month study. ANCOVA with age and body mass index as covariates showed that the baseline plasma BDNF levels in smokers were significantly lower than those in nonsmokers (F=4.626, p = 0.038). The plasma BDNF levels in the smokers significantly increased from baseline after the two-month smoking cessation period (Z= -3.059, p = 0.002). These findings suggest that BDNF may play a role in the pathophysiology of smoking behavior. (C) 2007 Published by Elsevier Ireland Ltd.