The Moderation Effect of BDNF Genotype and Self-Reported Habitual Physical Activity Levels on Age of Onset, Disease Progression, and Postural Instability in Parkinson's

Abstract

Background and Purpose: Brain-derived neurotrophic factor (BDNF) levels have been reported to play an important role in driving neuroprotection in people with neurologic disorders, and levels of BDNF are known to increase in response to physical activity. Moreover, the level of BDNF produced is also affected by BDNF genotype. It is not known, however, whether one’s BDNF genotype interacts with physical activity throughout life to affect a neuroprotective response in people with Parkinson’s disease (PD). Therefore, the purpose of this study was to determine if BDNF genotype interacts with lifetime self-reported physical activity levels to affect disease severity and progression as determined by measures of gait, balance, and PD motor function. Methods: Included in the study were 28 individuals with idiopathic PD. DNA collected from buccal cells was used to determine BDNF genotype. Self-report measures included a modified version of the Lifetime Physical Activity Questionnaire (LPAQ), the Fear of Falling Avoidance Behavior Questionnaire (FFABQ), and the Activities-Specific Balance Confidence scale (ABC), as well as demographic information. Tester- administered measures included the Mini-Balance Evaluations Test (MiniBESTest), a gait and balance performance battery, and the Movement Disorder Society – Unified Parkinson’s Disease Rating Scale III (MDS-UPDRS-III), an observational assessment of motor function. Results: There was not a significant interaction between BDNF genotype and self-reported history of physical activity on measures of gait and balance in individuals with PD. There was also no interaction between BDNF genotype and history of physical activity on age of PD onset or severity of disease. Discussion: Preliminary results did not reveal any differential effects of BDNF genotype and history of physical activity effecting gait and balance, age of disease onset, or disease severity in individuals with PD. While all of the analyses are currently underpowered due to sample size, there were trends to indicate that there may be some validity to the original hypotheses. Data collection for this study is ongoing.