Assessment of attention, memory, and salivary brain-derived neurotrophic factor in chronic smokers: A cross-sectional observational study

Abstract

Objective: Chronic smoking leads to cognitive impairments and affects the peripheral brain-derived neurotrophic factor (BDNF) levels. BDNF is responsible for synaptic plasticity and memory. The effect of chronic smoking on attention and salivary BDNF is yet to be explored. The purpose of the study is to find the assessment and comparison of attention and memory-span between chronic smokers and controls and also to study the effect of smoking on salivary BDNF level and compare this with that of controls. Materials and Methods: The present cross-sectional study was conducted in a dental college between March 2019 and October 2020. Participants took part in the computerized forward digit-span test (psychological experiment building language). Quantification of salivary BDNF from unstimulated saliva samples was done using the sandwich ELISA. Results: The results showed a significant decline in memory span (P < 0.05, Hedge's - g = −0.612) and correct responses (P < 0.05, Hedge's - g = −0.747) for the case group. There was an insignificant difference in salivary BDNF levels (P > 0.05, Hedge's - g = 0.007) between the two groups. Pearson's correlation showed a strong correlation between salivary BDNF and smoking severity (P < 0.05). Conclusion: The present study showed impaired attention and memory span among smokers. Salivary BDNF elucidated relation with smoking severity and physical dependence. The study indicates the important role of salivary BDNF to assess cognitive functioning.