Exploring the Impact of Modifiable Factors on Serum BDNF in Psychiatric Patients and Community Controls

Galen Chan,1 Tea Rosic,2,3 Stanislav Pasyk,2 Mahshid Dehghan,4 Zainab Samaan2,3 1Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada; 2Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada; 3Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, ON, Canada; 4Population Health Research Institute, McMaster University, Hamilton, Ontario, CanadaCorrespondence: Zainab Samaan Department of Psychiatry and Behavioural NeurosciencesMcMaster University, Hamilton, ON, CanadaTel +1 905 522 1155 ext. 39215Fax +1 905 528 2814Email samaanz@mcmaster.caBackground: Brain-derived neurotrophic factor (BDNF) has been a focus of psychiatric research for the past two decades. BDNF has been shown to impact neural function and development. Studies have investigated serum BDNF as a biomarker for psychiatric disorders such as depression and schizophrenia. In some studies, investigators attempt to control for variables such as smoking status, exercise, or diet. However, the relationship between these factors and BDNF is not clearly established. Furthermore, some studies have questioned whether a difference in the impact of BDNF exists between psychiatric and healthy populations.Purpose: We aim to examine the association between serum BDNF levels and modifiable risk factors such as body mass index (BMI), smoking, exercise levels, and diet. Subsequently, we aim to examine whether the relationship between these risk factors and serum BDNF is different between psychiatric and control populations.Patients and Methods: We use cross-sectional data from an age- and sex-matched case–control study of participants with psychiatric inpatients and community controls without psychiatric diagnoses. Participants completed comprehensive assessments at study enrolment including sociodemographic information, smoking status, exercise, diet, and BMI. Serum BDNF levels were collected from