Role of Cardiovascular Risk in Associations of Brain-Derived Neurotrophic Factor with Longitudinal Brain and Cognitive Trajectories in Older Adults

BACKGROUND: Higher levels of brain-derived neurotrophic factor (BDNF) have been associated with better neurocognitive outcomes. BDNF is present in cardiovascular tissue, and some evidence suggests it may benefit cardiovascular function. The current study assessed whether there is a mediating and/or moderating role of cardiovascular health in the relationship between BDNF and brain and cognitive outcomes. METHOD: We examined longitudinal data from 397 older adults (aged 54-89;164 females, 233 males) enrolled in the Alzheimer's Disease Neuroimaging Initiative with available plasma BDNF, medical, neuroimaging, and cognitive assessments. We used path analysis and linear regression to estimate the mediating and moderating roles of two measures of cardiovascular health, the Framingham Risk Score (FRS) and pulse pressure, in the relationships between BDNF and longitudinal changes in brain structure (white matter hyperintensity volume, hippocampal volume, and primary visual cortex volume) and cognitive function (executive function, episodic memory, and language). RESULTS: There was no significant association of plasma BDNF with FRS or pulse pressure (ps > 0.31), precluding mediation. There were no robust associations between BDNF and longitudinal change in any brain structural or cognitive measures (ps > .12). Higher FRS was significantly associated with greater increases in WMH volume (ps < .01). FRS and pulse pressure were not associated with any other brain structural or cognitive outcomes (ps > .07). CONCLUSION: These results suggest that cardiovascular health may not play an important role in the influence of BDNF on neurocognitive health in older adults.