Is Brain-Derived Neurotrophic Factor Associated With Smoking Initiation? Replication Using a Large Finnish Population Sample

• Published in: Nicotine & tobacco research 2020-02, Vol.22 (2), p.293-296
• Main Authors: Korhonen, Tellervo, Loukola, Anu, Hällfors, Jenni, Salomaa, Veikko, Kaprio, Jaakko
• Format: Article
• Language: English
• ISSN: 1462-2203; 1469-994X
• DOI: 10.1093/ntr/nty218

Abstract Introduction Brain-derived neurotrophic factor (BDNF) is a growth factor in the central nervous system. There is evidence for the involvement of BDNF in addictions and mental disorders. We aimed to replicate the earlier reported association of a functional genetic variant of BDNF with smoking initiation (SI) using a large population-based sample and to test whether the association is independent of depression. Methods Our sample was drawn from the Finnish population-based FINRISK surveys conducted in 1992, 1997, 2002, and 2007. We had nonmissing data on the genotype BDNF  Val66Met (G/A) variant (rs6265) and self-reported never (n = 10 619) versus ever (n = 16 028) smoking among 26 647 adults aged 25–74 years. The association between BDNF  Val66Met and SI was modeled using logistic regression adjusted for age and sex, and in secondary analyses also for depression. Depression was defined as self-reported depression diagnosed or treated by physician during the past year. Results The sex- and age-adjusted analysis confirmed that the major (Val) allele increased the risk of being a lifetime ever smoker (per allele odds ratio [OR] = 1.07; 95% CI = 1.01 to 1.12; p = .01). When depression, which itself was significantly associated with SI (OR = 1.58; 95% CI = 1.37 to 1.82; p < .001), was added to the model, the association of the gene with SI remained significant (per allele OR = 1.06; 95% CI = 1.01 to 1.12; p = .01). Exclusion of depressed individuals did not change the results (OR = 1.06; 95% CI = 1.01 to 1.12; p = .02). Conclusions In a Finnish population sample, we replicated the earlier reported association of BDNF Val66Met with SI. Our data further suggest that this association is independent of depression. Implications Earlier finding about the association between the BDNF gene and smoking initiation is replicated and shown to be independent of depression within Finnish adult population.